Merge remote-tracking branch 'remotes/famz/tags/staging-pull-request' into staging

# gpg: Signature made Thu 08 Feb 2018 01:29:22 GMT
# gpg:                using RSA key CA35624C6A9171C6
# gpg: Good signature from "Fam Zheng <famz@redhat.com>"
# Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6

* remotes/famz/tags/staging-pull-request:
  docs: Add docs/devel/testing.rst
  qapi: Add NVMe driver options to the schema
  docs: Add section for NVMe VFIO driver
  block: Move NVMe constants to a separate header
  qemu-img: Map bench buffer
  block/nvme: Implement .bdrv_(un)register_buf
  block: Introduce buf register API
  block: Add VFIO based NVMe driver
  util: Introduce vfio helpers
  stubs: Add stubs for ram block API
  curl: convert to CoQueue
  coroutine-lock: make qemu_co_enter_next thread-safe
  coroutine-lock: convert CoQueue to use QemuLockable
  lockable: add QemuLockable
  test-coroutine: add simple CoMutex test
  docker: change Fedora base image to fedora:27

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

33 files changed, 3580 insertions, 829 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index bbc3a61..301b699 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1888,6 +1888,12 @@ L: qemu-block@nongnu.org
 S: Supported
 F: block/null.c
 
+NVMe Block Driver
+M: Fam Zheng <famz@redhat.com>
+L: qemu-block@nongnu.org
+S: Supported
+F: block/nvme*
+
 Bootdevice
 M: Gonglei <arei.gonglei@huawei.com>
 S: Maintained
diff --git a/block/Makefile.objs b/block/Makefile.objs
index a73387f..aede94f 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -11,6 +11,7 @@ block-obj-$(CONFIG_POSIX) += file-posix.o
 block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 block-obj-y += null.o mirror.o commit.o io.o
 block-obj-y += throttle-groups.o
+block-obj-$(CONFIG_LINUX) += nvme.o
 
 block-obj-y += nbd.o nbd-client.o sheepdog.o
 block-obj-$(CONFIG_LIBISCSI) += iscsi.o
diff --git a/block/block-backend.c b/block/block-backend.c
index baef8e7..f66349c 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2096,3 +2096,13 @@ static void blk_root_drained_end(BdrvChild *child)
         }
     }
 }
+
+void blk_register_buf(BlockBackend *blk, void *host, size_t size)
+{
+    bdrv_register_buf(blk_bs(blk), host, size);
+}
+
+void blk_unregister_buf(BlockBackend *blk, void *host)
+{
+    bdrv_unregister_buf(blk_bs(blk), host);
+}
diff --git a/block/curl.c b/block/curl.c
index 35cf417..cd578d3 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -101,8 +101,6 @@ typedef struct CURLAIOCB {
 
     size_t start;
     size_t end;
-
-    QSIMPLEQ_ENTRY(CURLAIOCB) next;
 } CURLAIOCB;
 
 typedef struct CURLSocket {
@@ -138,7 +136,7 @@ typedef struct BDRVCURLState {
     bool accept_range;
     AioContext *aio_context;
     QemuMutex mutex;
-    QSIMPLEQ_HEAD(, CURLAIOCB) free_state_waitq;
+    CoQueue free_state_waitq;
     char *username;
     char *password;
     char *proxyusername;
@@ -538,7 +536,6 @@ static int curl_init_state(BDRVCURLState *s, CURLState *state)
 /* Called with s->mutex held.  */
 static void curl_clean_state(CURLState *s)
 {
-    CURLAIOCB *next;
     int j;
     for (j = 0; j < CURL_NUM_ACB; j++) {
         assert(!s->acb[j]);
@@ -556,13 +553,7 @@ static void curl_clean_state(CURLState *s)
 
     s->in_use = 0;
 
-    next = QSIMPLEQ_FIRST(&s->s->free_state_waitq);
-    if (next) {
-        QSIMPLEQ_REMOVE_HEAD(&s->s->free_state_waitq, next);
-        qemu_mutex_unlock(&s->s->mutex);
-        aio_co_wake(next->co);
-        qemu_mutex_lock(&s->s->mutex);
-    }
+    qemu_co_enter_next(&s->s->free_state_waitq, &s->s->mutex);
 }
 
 static void curl_parse_filename(const char *filename, QDict *options,
@@ -784,7 +775,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     DPRINTF("CURL: Opening %s\n", file);
-    QSIMPLEQ_INIT(&s->free_state_waitq);
+    qemu_co_queue_init(&s->free_state_waitq);
     s->aio_context = bdrv_get_aio_context(bs);
     s->url = g_strdup(file);
     qemu_mutex_lock(&s->mutex);
@@ -888,10 +879,7 @@ static void curl_setup_preadv(BlockDriverState *bs, CURLAIOCB *acb)
         if (state) {
             break;
         }
-        QSIMPLEQ_INSERT_TAIL(&s->free_state_waitq, acb, next);
-        qemu_mutex_unlock(&s->mutex);
-        qemu_coroutine_yield();
-        qemu_mutex_lock(&s->mutex);
+        qemu_co_queue_wait(&s->free_state_waitq, &s->mutex);
     }
 
     if (curl_init_state(s, state) < 0) {
diff --git a/block/io.c b/block/io.c
index 7ea4023..89d0745 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2825,3 +2825,27 @@ void bdrv_io_unplug(BlockDriverState *bs)
         bdrv_io_unplug(child->bs);
     }
 }
+
+void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size)
+{
+    BdrvChild *child;
+
+    if (bs->drv && bs->drv->bdrv_register_buf) {
+        bs->drv->bdrv_register_buf(bs, host, size);
+    }
+    QLIST_FOREACH(child, &bs->children, next) {
+        bdrv_register_buf(child->bs, host, size);
+    }
+}
+
+void bdrv_unregister_buf(BlockDriverState *bs, void *host)
+{
+    BdrvChild *child;
+
+    if (bs->drv && bs->drv->bdrv_unregister_buf) {
+        bs->drv->bdrv_unregister_buf(bs, host);
+    }
+    QLIST_FOREACH(child, &bs->children, next) {
+        bdrv_unregister_buf(child->bs, host);
+    }
+}
diff --git a/block/nvme.c b/block/nvme.c
new file mode 100644
index 0000000..e9d0e21
--- /dev/null
+++ b/block/nvme.c
@@ -0,0 +1,1201 @@
+/*
+ * NVMe block driver based on vfio
+ *
+ * Copyright 2016 - 2018 Red Hat, Inc.
+ *
+ * Authors:
+ *   Fam Zheng <famz@redhat.com>
+ *   Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include <linux/vfio.h>
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
+#include "qemu/error-report.h"
+#include "qemu/cutils.h"
+#include "qemu/vfio-helpers.h"
+#include "block/block_int.h"
+#include "trace.h"
+
+#include "block/nvme.h"
+
+#define NVME_SQ_ENTRY_BYTES 64
+#define NVME_CQ_ENTRY_BYTES 16
+#define NVME_QUEUE_SIZE 128
+#define NVME_BAR_SIZE 8192
+
+typedef struct {
+    int32_t  head, tail;
+    uint8_t  *queue;
+    uint64_t iova;
+    /* Hardware MMIO register */
+    volatile uint32_t *doorbell;
+} NVMeQueue;
+
+typedef struct {
+    BlockCompletionFunc *cb;
+    void *opaque;
+    int cid;
+    void *prp_list_page;
+    uint64_t prp_list_iova;
+    bool busy;
+} NVMeRequest;
+
+typedef struct {
+    CoQueue     free_req_queue;
+    QemuMutex   lock;
+
+    /* Fields protected by BQL */
+    int         index;
+    uint8_t     *prp_list_pages;
+
+    /* Fields protected by @lock */
+    NVMeQueue   sq, cq;
+    int         cq_phase;
+    NVMeRequest reqs[NVME_QUEUE_SIZE];
+    bool        busy;
+    int         need_kick;
+    int         inflight;
+} NVMeQueuePair;
+
+/* Memory mapped registers */
+typedef volatile struct {
+    uint64_t cap;
+    uint32_t vs;
+    uint32_t intms;
+    uint32_t intmc;
+    uint32_t cc;
+    uint32_t reserved0;
+    uint32_t csts;
+    uint32_t nssr;
+    uint32_t aqa;
+    uint64_t asq;
+    uint64_t acq;
+    uint32_t cmbloc;
+    uint32_t cmbsz;
+    uint8_t  reserved1[0xec0];
+    uint8_t  cmd_set_specfic[0x100];
+    uint32_t doorbells[];
+} QEMU_PACKED NVMeRegs;
+
+QEMU_BUILD_BUG_ON(offsetof(NVMeRegs, doorbells) != 0x1000);
+
+typedef struct {
+    AioContext *aio_context;
+    QEMUVFIOState *vfio;
+    NVMeRegs *regs;
+    /* The submission/completion queue pairs.
+     * [0]: admin queue.
+     * [1..]: io queues.
+     */
+    NVMeQueuePair **queues;
+    int nr_queues;
+    size_t page_size;
+    /* How many uint32_t elements does each doorbell entry take. */
+    size_t doorbell_scale;
+    bool write_cache_supported;
+    EventNotifier irq_notifier;
+    uint64_t nsze; /* Namespace size reported by identify command */
+    int nsid;      /* The namespace id to read/write data. */
+    uint64_t max_transfer;
+    int plugged;
+
+    CoMutex dma_map_lock;
+    CoQueue dma_flush_queue;
+
+    /* Total size of mapped qiov, accessed under dma_map_lock */
+    int dma_map_count;
+} BDRVNVMeState;
+
+#define NVME_BLOCK_OPT_DEVICE "device"
+#define NVME_BLOCK_OPT_NAMESPACE "namespace"
+
+static QemuOptsList runtime_opts = {
+    .name = "nvme",
+    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
+    .desc = {
+        {
+            .name = NVME_BLOCK_OPT_DEVICE,
+            .type = QEMU_OPT_STRING,
+            .help = "NVMe PCI device address",
+        },
+        {
+            .name = NVME_BLOCK_OPT_NAMESPACE,
+            .type = QEMU_OPT_NUMBER,
+            .help = "NVMe namespace",
+        },
+        { /* end of list */ }
+    },
+};
+
+static void nvme_init_queue(BlockDriverState *bs, NVMeQueue *q,
+                            int nentries, int entry_bytes, Error **errp)
+{
+    BDRVNVMeState *s = bs->opaque;
+    size_t bytes;
+    int r;
+
+    bytes = ROUND_UP(nentries * entry_bytes, s->page_size);
+    q->head = q->tail = 0;
+    q->queue = qemu_try_blockalign0(bs, bytes);
+
+    if (!q->queue) {
+        error_setg(errp, "Cannot allocate queue");
+        return;
+    }
+    r = qemu_vfio_dma_map(s->vfio, q->queue, bytes, false, &q->iova);
+    if (r) {
+        error_setg(errp, "Cannot map queue");
+    }
+}
+
+static void nvme_free_queue_pair(BlockDriverState *bs, NVMeQueuePair *q)
+{
+    qemu_vfree(q->prp_list_pages);
+    qemu_vfree(q->sq.queue);
+    qemu_vfree(q->cq.queue);
+    qemu_mutex_destroy(&q->lock);
+    g_free(q);
+}
+
+static void nvme_free_req_queue_cb(void *opaque)
+{
+    NVMeQueuePair *q = opaque;
+
+    qemu_mutex_lock(&q->lock);
+    while (qemu_co_enter_next(&q->free_req_queue, &q->lock)) {
+        /* Retry all pending requests */
+    }
+    qemu_mutex_unlock(&q->lock);
+}
+
+static NVMeQueuePair *nvme_create_queue_pair(BlockDriverState *bs,
+                                             int idx, int size,
+                                             Error **errp)
+{
+    int i, r;
+    BDRVNVMeState *s = bs->opaque;
+    Error *local_err = NULL;
+    NVMeQueuePair *q = g_new0(NVMeQueuePair, 1);
+    uint64_t prp_list_iova;
+
+    qemu_mutex_init(&q->lock);
+    q->index = idx;
+    qemu_co_queue_init(&q->free_req_queue);
+    q->prp_list_pages = qemu_blockalign0(bs, s->page_size * NVME_QUEUE_SIZE);
+    r = qemu_vfio_dma_map(s->vfio, q->prp_list_pages,
+                          s->page_size * NVME_QUEUE_SIZE,
+                          false, &prp_list_iova);
+    if (r) {
+        goto fail;
+    }
+    for (i = 0; i < NVME_QUEUE_SIZE; i++) {
+        NVMeRequest *req = &q->reqs[i];
+        req->cid = i + 1;
+        req->prp_list_page = q->prp_list_pages + i * s->page_size;
+        req->prp_list_iova = prp_list_iova + i * s->page_size;
+    }
+    nvme_init_queue(bs, &q->sq, size, NVME_SQ_ENTRY_BYTES, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto fail;
+    }
+    q->sq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale];
+
+    nvme_init_queue(bs, &q->cq, size, NVME_CQ_ENTRY_BYTES, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto fail;
+    }
+    q->cq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale + 1];
+
+    return q;
+fail:
+    nvme_free_queue_pair(bs, q);
+    return NULL;
+}
+
+/* With q->lock */
+static void nvme_kick(BDRVNVMeState *s, NVMeQueuePair *q)
+{
+    if (s->plugged || !q->need_kick) {
+        return;
+    }
+    trace_nvme_kick(s, q->index);
+    assert(!(q->sq.tail & 0xFF00));
+    /* Fence the write to submission queue entry before notifying the device. */
+    smp_wmb();
+    *q->sq.doorbell = cpu_to_le32(q->sq.tail);
+    q->inflight += q->need_kick;
+    q->need_kick = 0;
+}
+
+/* Find a free request element if any, otherwise:
+ * a) if in coroutine context, try to wait for one to become available;
+ * b) if not in coroutine, return NULL;
+ */
+static NVMeRequest *nvme_get_free_req(NVMeQueuePair *q)
+{
+    int i;
+    NVMeRequest *req = NULL;
+
+    qemu_mutex_lock(&q->lock);
+    while (q->inflight + q->need_kick > NVME_QUEUE_SIZE - 2) {
+        /* We have to leave one slot empty as that is the full queue case (head
+         * == tail + 1). */
+        if (qemu_in_coroutine()) {
+            trace_nvme_free_req_queue_wait(q);
+            qemu_co_queue_wait(&q->free_req_queue, &q->lock);
+        } else {
+            qemu_mutex_unlock(&q->lock);
+            return NULL;
+        }
+    }
+    for (i = 0; i < NVME_QUEUE_SIZE; i++) {
+        if (!q->reqs[i].busy) {
+            q->reqs[i].busy = true;
+            req = &q->reqs[i];
+            break;
+        }
+    }
+    /* We have checked inflight and need_kick while holding q->lock, so one
+     * free req must be available. */
+    assert(req);
+    qemu_mutex_unlock(&q->lock);
+    return req;
+}
+
+static inline int nvme_translate_error(const NvmeCqe *c)
+{
+    uint16_t status = (le16_to_cpu(c->status) >> 1) & 0xFF;
+    if (status) {
+        trace_nvme_error(le32_to_cpu(c->result),
+                         le16_to_cpu(c->sq_head),
+                         le16_to_cpu(c->sq_id),
+                         le16_to_cpu(c->cid),
+                         le16_to_cpu(status));
+    }
+    switch (status) {
+    case 0:
+        return 0;
+    case 1:
+        return -ENOSYS;
+    case 2:
+        return -EINVAL;
+    default:
+        return -EIO;
+    }
+}
+
+/* With q->lock */
+static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q)
+{
+    bool progress = false;
+    NVMeRequest *preq;
+    NVMeRequest req;
+    NvmeCqe *c;
+
+    trace_nvme_process_completion(s, q->index, q->inflight);
+    if (q->busy || s->plugged) {
+        trace_nvme_process_completion_queue_busy(s, q->index);
+        return false;
+    }
+    q->busy = true;
+    assert(q->inflight >= 0);
+    while (q->inflight) {
+        int16_t cid;
+        c = (NvmeCqe *)&q->cq.queue[q->cq.head * NVME_CQ_ENTRY_BYTES];
+        if (!c->cid || (le16_to_cpu(c->status) & 0x1) == q->cq_phase) {
+            break;
+        }
+        q->cq.head = (q->cq.head + 1) % NVME_QUEUE_SIZE;
+        if (!q->cq.head) {
+            q->cq_phase = !q->cq_phase;
+        }
+        cid = le16_to_cpu(c->cid);
+        if (cid == 0 || cid > NVME_QUEUE_SIZE) {
+            fprintf(stderr, "Unexpected CID in completion queue: %" PRIu32 "\n",
+                    cid);
+            continue;
+        }
+        assert(cid <= NVME_QUEUE_SIZE);
+        trace_nvme_complete_command(s, q->index, cid);
+        preq = &q->reqs[cid - 1];
+        req = *preq;
+        assert(req.cid == cid);
+        assert(req.cb);
+        preq->busy = false;
+        preq->cb = preq->opaque = NULL;
+        qemu_mutex_unlock(&q->lock);
+        req.cb(req.opaque, nvme_translate_error(c));
+        qemu_mutex_lock(&q->lock);
+        c->cid = cpu_to_le16(0);
+        q->inflight--;
+        /* Flip Phase Tag bit. */
+        c->status = cpu_to_le16(le16_to_cpu(c->status) ^ 0x1);
+        progress = true;
+    }
+    if (progress) {
+        /* Notify the device so it can post more completions. */
+        smp_mb_release();
+        *q->cq.doorbell = cpu_to_le32(q->cq.head);
+        if (!qemu_co_queue_empty(&q->free_req_queue)) {
+            aio_bh_schedule_oneshot(s->aio_context, nvme_free_req_queue_cb, q);
+        }
+    }
+    q->busy = false;
+    return progress;
+}
+
+static void nvme_trace_command(const NvmeCmd *cmd)
+{
+    int i;
+
+    for (i = 0; i < 8; ++i) {
+        uint8_t *cmdp = (uint8_t *)cmd + i * 8;
+        trace_nvme_submit_command_raw(cmdp[0], cmdp[1], cmdp[2], cmdp[3],
+                                      cmdp[4], cmdp[5], cmdp[6], cmdp[7]);
+    }
+}
+
+static void nvme_submit_command(BDRVNVMeState *s, NVMeQueuePair *q,
+                                NVMeRequest *req,
+                                NvmeCmd *cmd, BlockCompletionFunc cb,
+                                void *opaque)
+{
+    assert(!req->cb);
+    req->cb = cb;
+    req->opaque = opaque;
+    cmd->cid = cpu_to_le32(req->cid);
+
+    trace_nvme_submit_command(s, q->index, req->cid);
+    nvme_trace_command(cmd);
+    qemu_mutex_lock(&q->lock);
+    memcpy((uint8_t *)q->sq.queue +
+           q->sq.tail * NVME_SQ_ENTRY_BYTES, cmd, sizeof(*cmd));
+    q->sq.tail = (q->sq.tail + 1) % NVME_QUEUE_SIZE;
+    q->need_kick++;
+    nvme_kick(s, q);
+    nvme_process_completion(s, q);
+    qemu_mutex_unlock(&q->lock);
+}
+
+static void nvme_cmd_sync_cb(void *opaque, int ret)
+{
+    int *pret = opaque;
+    *pret = ret;
+}
+
+static int nvme_cmd_sync(BlockDriverState *bs, NVMeQueuePair *q,
+                         NvmeCmd *cmd)
+{
+    NVMeRequest *req;
+    BDRVNVMeState *s = bs->opaque;
+    int ret = -EINPROGRESS;
+    req = nvme_get_free_req(q);
+    if (!req) {
+        return -EBUSY;
+    }
+    nvme_submit_command(s, q, req, cmd, nvme_cmd_sync_cb, &ret);
+
+    BDRV_POLL_WHILE(bs, ret == -EINPROGRESS);
+    return ret;
+}
+
+static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
+{
+    BDRVNVMeState *s = bs->opaque;
+    NvmeIdCtrl *idctrl;
+    NvmeIdNs *idns;
+    uint8_t *resp;
+    int r;
+    uint64_t iova;
+    NvmeCmd cmd = {
+        .opcode = NVME_ADM_CMD_IDENTIFY,
+        .cdw10 = cpu_to_le32(0x1),
+    };
+
+    resp = qemu_try_blockalign0(bs, sizeof(NvmeIdCtrl));
+    if (!resp) {
+        error_setg(errp, "Cannot allocate buffer for identify response");
+        goto out;
+    }
+    idctrl = (NvmeIdCtrl *)resp;
+    idns = (NvmeIdNs *)resp;
+    r = qemu_vfio_dma_map(s->vfio, resp, sizeof(NvmeIdCtrl), true, &iova);
+    if (r) {
+        error_setg(errp, "Cannot map buffer for DMA");
+        goto out;
+    }
+    cmd.prp1 = cpu_to_le64(iova);
+
+    if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+        error_setg(errp, "Failed to identify controller");
+        goto out;
+    }
+
+    if (le32_to_cpu(idctrl->nn) < namespace) {
+        error_setg(errp, "Invalid namespace");
+        goto out;
+    }
+    s->write_cache_supported = le32_to_cpu(idctrl->vwc) & 0x1;
+    s->max_transfer = (idctrl->mdts ? 1 << idctrl->mdts : 0) * s->page_size;
+    /* For now the page list buffer per command is one page, to hold at most
+     * s->page_size / sizeof(uint64_t) entries. */
+    s->max_transfer = MIN_NON_ZERO(s->max_transfer,
+                          s->page_size / sizeof(uint64_t) * s->page_size);
+
+    memset(resp, 0, 4096);
+
+    cmd.cdw10 = 0;
+    cmd.nsid = cpu_to_le32(namespace);
+    if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+        error_setg(errp, "Failed to identify namespace");
+        goto out;
+    }
+
+    s->nsze = le64_to_cpu(idns->nsze);
+
+out:
+    qemu_vfio_dma_unmap(s->vfio, resp);
+    qemu_vfree(resp);
+}
+
+static bool nvme_poll_queues(BDRVNVMeState *s)
+{
+    bool progress = false;
+    int i;
+
+    for (i = 0; i < s->nr_queues; i++) {
+        NVMeQueuePair *q = s->queues[i];
+        qemu_mutex_lock(&q->lock);
+        while (nvme_process_completion(s, q)) {
+            /* Keep polling */
+            progress = true;
+        }
+        qemu_mutex_unlock(&q->lock);
+    }
+    return progress;
+}
+
+static void nvme_handle_event(EventNotifier *n)
+{
+    BDRVNVMeState *s = container_of(n, BDRVNVMeState, irq_notifier);
+
+    trace_nvme_handle_event(s);
+    aio_context_acquire(s->aio_context);
+    event_notifier_test_and_clear(n);
+    nvme_poll_queues(s);
+    aio_context_release(s->aio_context);
+}
+
+static bool nvme_add_io_queue(BlockDriverState *bs, Error **errp)
+{
+    BDRVNVMeState *s = bs->opaque;
+    int n = s->nr_queues;
+    NVMeQueuePair *q;
+    NvmeCmd cmd;
+    int queue_size = NVME_QUEUE_SIZE;
+
+    q = nvme_create_queue_pair(bs, n, queue_size, errp);
+    if (!q) {
+        return false;
+    }
+    cmd = (NvmeCmd) {
+        .opcode = NVME_ADM_CMD_CREATE_CQ,
+        .prp1 = cpu_to_le64(q->cq.iova),
+        .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | (n & 0xFFFF)),
+        .cdw11 = cpu_to_le32(0x3),
+    };
+    if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+        error_setg(errp, "Failed to create io queue [%d]", n);
+        nvme_free_queue_pair(bs, q);
+        return false;
+    }
+    cmd = (NvmeCmd) {
+        .opcode = NVME_ADM_CMD_CREATE_SQ,
+        .prp1 = cpu_to_le64(q->sq.iova),
+        .cdw10 = cpu_to_le32(((queue_size - 1) << 16) | (n & 0xFFFF)),
+        .cdw11 = cpu_to_le32(0x1 | (n << 16)),
+    };
+    if (nvme_cmd_sync(bs, s->queues[0], &cmd)) {
+        error_setg(errp, "Failed to create io queue [%d]", n);
+        nvme_free_queue_pair(bs, q);
+        return false;
+    }
+    s->queues = g_renew(NVMeQueuePair *, s->queues, n + 1);
+    s->queues[n] = q;
+    s->nr_queues++;
+    return true;
+}
+
+static bool nvme_poll_cb(void *opaque)
+{
+    EventNotifier *e = opaque;
+    BDRVNVMeState *s = container_of(e, BDRVNVMeState, irq_notifier);
+    bool progress = false;
+
+    trace_nvme_poll_cb(s);
+    progress = nvme_poll_queues(s);
+    return progress;
+}
+
+static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
+                     Error **errp)
+{
+    BDRVNVMeState *s = bs->opaque;
+    int ret;
+    uint64_t cap;
+    uint64_t timeout_ms;
+    uint64_t deadline, now;
+    Error *local_err = NULL;
+
+    qemu_co_mutex_init(&s->dma_map_lock);
+    qemu_co_queue_init(&s->dma_flush_queue);
+    s->nsid = namespace;
+    s->aio_context = bdrv_get_aio_context(bs);
+    ret = event_notifier_init(&s->irq_notifier, 0);
+    if (ret) {
+        error_setg(errp, "Failed to init event notifier");
+        return ret;
+    }
+
+    s->vfio = qemu_vfio_open_pci(device, errp);
+    if (!s->vfio) {
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    s->regs = qemu_vfio_pci_map_bar(s->vfio, 0, 0, NVME_BAR_SIZE, errp);
+    if (!s->regs) {
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    /* Perform initialize sequence as described in NVMe spec "7.6.1
+     * Initialization". */
+
+    cap = le64_to_cpu(s->regs->cap);
+    if (!(cap & (1ULL << 37))) {
+        error_setg(errp, "Device doesn't support NVMe command set");
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    s->page_size = MAX(4096, 1 << (12 + ((cap >> 48) & 0xF)));
+    s->doorbell_scale = (4 << (((cap >> 32) & 0xF))) / sizeof(uint32_t);
+    bs->bl.opt_mem_alignment = s->page_size;
+    timeout_ms = MIN(500 * ((cap >> 24) & 0xFF), 30000);
+
+    /* Reset device to get a clean state. */
+    s->regs->cc = cpu_to_le32(le32_to_cpu(s->regs->cc) & 0xFE);
+    /* Wait for CSTS.RDY = 0. */
+    deadline = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ms * 1000000ULL;
+    while (le32_to_cpu(s->regs->csts) & 0x1) {
+        if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) > deadline) {
+            error_setg(errp, "Timeout while waiting for device to reset (%"
+                             PRId64 " ms)",
+                       timeout_ms);
+            ret = -ETIMEDOUT;
+            goto fail;
+        }
+    }
+
+    /* Set up admin queue. */
+    s->queues = g_new(NVMeQueuePair *, 1);
+    s->nr_queues = 1;
+    s->queues[0] = nvme_create_queue_pair(bs, 0, NVME_QUEUE_SIZE, errp);
+    if (!s->queues[0]) {
+        ret = -EINVAL;
+        goto fail;
+    }
+    QEMU_BUILD_BUG_ON(NVME_QUEUE_SIZE & 0xF000);
+    s->regs->aqa = cpu_to_le32((NVME_QUEUE_SIZE << 16) | NVME_QUEUE_SIZE);
+    s->regs->asq = cpu_to_le64(s->queues[0]->sq.iova);
+    s->regs->acq = cpu_to_le64(s->queues[0]->cq.iova);
+
+    /* After setting up all control registers we can enable device now. */
+    s->regs->cc = cpu_to_le32((ctz32(NVME_CQ_ENTRY_BYTES) << 20) |
+                              (ctz32(NVME_SQ_ENTRY_BYTES) << 16) |
+                              0x1);
+    /* Wait for CSTS.RDY = 1. */
+    now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+    deadline = now + timeout_ms * 1000000;
+    while (!(le32_to_cpu(s->regs->csts) & 0x1)) {
+        if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) > deadline) {
+            error_setg(errp, "Timeout while waiting for device to start (%"
+                             PRId64 " ms)",
+                       timeout_ms);
+            ret = -ETIMEDOUT;
+            goto fail_queue;
+        }
+    }
+
+    ret = qemu_vfio_pci_init_irq(s->vfio, &s->irq_notifier,
+                                 VFIO_PCI_MSIX_IRQ_INDEX, errp);
+    if (ret) {
+        goto fail_queue;
+    }
+    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+                           false, nvme_handle_event, nvme_poll_cb);
+
+    nvme_identify(bs, namespace, errp);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        ret = -EIO;
+        goto fail_handler;
+    }
+
+    /* Set up command queues. */
+    if (!nvme_add_io_queue(bs, errp)) {
+        ret = -EIO;
+        goto fail_handler;
+    }
+    return 0;
+
+fail_handler:
+    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+                           false, NULL, NULL);
+fail_queue:
+    nvme_free_queue_pair(bs, s->queues[0]);
+fail:
+    g_free(s->queues);
+    qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
+    qemu_vfio_close(s->vfio);
+    event_notifier_cleanup(&s->irq_notifier);
+    return ret;
+}
+
+/* Parse a filename in the format of nvme://XXXX:XX:XX.X/X. Example:
+ *
+ *     nvme://0000:44:00.0/1
+ *
+ * where the "nvme://" is a fixed form of the protocol prefix, the middle part
+ * is the PCI address, and the last part is the namespace number starting from
+ * 1 according to the NVMe spec. */
+static void nvme_parse_filename(const char *filename, QDict *options,
+                                Error **errp)
+{
+    int pref = strlen("nvme://");
+
+    if (strlen(filename) > pref && !strncmp(filename, "nvme://", pref)) {
+        const char *tmp = filename + pref;
+        char *device;
+        const char *namespace;
+        unsigned long ns;
+        const char *slash = strchr(tmp, '/');
+        if (!slash) {
+            qdict_put(options, NVME_BLOCK_OPT_DEVICE,
+                      qstring_from_str(tmp));
+            return;
+        }
+        device = g_strndup(tmp, slash - tmp);
+        qdict_put(options, NVME_BLOCK_OPT_DEVICE, qstring_from_str(device));
+        g_free(device);
+        namespace = slash + 1;
+        if (*namespace && qemu_strtoul(namespace, NULL, 10, &ns)) {
+            error_setg(errp, "Invalid namespace '%s', positive number expected",
+                       namespace);
+            return;
+        }
+        qdict_put(options, NVME_BLOCK_OPT_NAMESPACE,
+                  qstring_from_str(*namespace ? namespace : "1"));
+    }
+}
+
+static int nvme_enable_disable_write_cache(BlockDriverState *bs, bool enable,
+                                           Error **errp)
+{
+    int ret;
+    BDRVNVMeState *s = bs->opaque;
+    NvmeCmd cmd = {
+        .opcode = NVME_ADM_CMD_SET_FEATURES,
+        .nsid = cpu_to_le32(s->nsid),
+        .cdw10 = cpu_to_le32(0x06),
+        .cdw11 = cpu_to_le32(enable ? 0x01 : 0x00),
+    };
+
+    ret = nvme_cmd_sync(bs, s->queues[0], &cmd);
+    if (ret) {
+        error_setg(errp, "Failed to configure NVMe write cache");
+    }
+    return ret;
+}
+
+static void nvme_close(BlockDriverState *bs)
+{
+    int i;
+    BDRVNVMeState *s = bs->opaque;
+
+    for (i = 0; i < s->nr_queues; ++i) {
+        nvme_free_queue_pair(bs, s->queues[i]);
+    }
+    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+                           false, NULL, NULL);
+    qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
+    qemu_vfio_close(s->vfio);
+}
+
+static int nvme_file_open(BlockDriverState *bs, QDict *options, int flags,
+                          Error **errp)
+{
+    const char *device;
+    QemuOpts *opts;
+    int namespace;
+    int ret;
+    BDRVNVMeState *s = bs->opaque;
+
+    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
+    qemu_opts_absorb_qdict(opts, options, &error_abort);
+    device = qemu_opt_get(opts, NVME_BLOCK_OPT_DEVICE);
+    if (!device) {
+        error_setg(errp, "'" NVME_BLOCK_OPT_DEVICE "' option is required");
+        qemu_opts_del(opts);
+        return -EINVAL;
+    }
+
+    namespace = qemu_opt_get_number(opts, NVME_BLOCK_OPT_NAMESPACE, 1);
+    ret = nvme_init(bs, device, namespace, errp);
+    qemu_opts_del(opts);
+    if (ret) {
+        goto fail;
+    }
+    if (flags & BDRV_O_NOCACHE) {
+        if (!s->write_cache_supported) {
+            error_setg(errp,
+                       "NVMe controller doesn't support write cache configuration");
+            ret = -EINVAL;
+        } else {
+            ret = nvme_enable_disable_write_cache(bs, !(flags & BDRV_O_NOCACHE),
+                                                  errp);
+        }
+        if (ret) {
+            goto fail;
+        }
+    }
+    bs->supported_write_flags = BDRV_REQ_FUA;
+    return 0;
+fail:
+    nvme_close(bs);
+    return ret;
+}
+
+static int64_t nvme_getlength(BlockDriverState *bs)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    return s->nsze << BDRV_SECTOR_BITS;
+}
+
+/* Called with s->dma_map_lock */
+static coroutine_fn int nvme_cmd_unmap_qiov(BlockDriverState *bs,
+                                            QEMUIOVector *qiov)
+{
+    int r = 0;
+    BDRVNVMeState *s = bs->opaque;
+
+    s->dma_map_count -= qiov->size;
+    if (!s->dma_map_count && !qemu_co_queue_empty(&s->dma_flush_queue)) {
+        r = qemu_vfio_dma_reset_temporary(s->vfio);
+        if (!r) {
+            qemu_co_queue_restart_all(&s->dma_flush_queue);
+        }
+    }
+    return r;
+}
+
+/* Called with s->dma_map_lock */
+static coroutine_fn int nvme_cmd_map_qiov(BlockDriverState *bs, NvmeCmd *cmd,
+                                          NVMeRequest *req, QEMUIOVector *qiov)
+{
+    BDRVNVMeState *s = bs->opaque;
+    uint64_t *pagelist = req->prp_list_page;
+    int i, j, r;
+    int entries = 0;
+
+    assert(qiov->size);
+    assert(QEMU_IS_ALIGNED(qiov->size, s->page_size));
+    assert(qiov->size / s->page_size <= s->page_size / sizeof(uint64_t));
+    for (i = 0; i < qiov->niov; ++i) {
+        bool retry = true;
+        uint64_t iova;
+try_map:
+        r = qemu_vfio_dma_map(s->vfio,
+                              qiov->iov[i].iov_base,
+                              qiov->iov[i].iov_len,
+                              true, &iova);
+        if (r == -ENOMEM && retry) {
+            retry = false;
+            trace_nvme_dma_flush_queue_wait(s);
+            if (s->dma_map_count) {
+                trace_nvme_dma_map_flush(s);
+                qemu_co_queue_wait(&s->dma_flush_queue, &s->dma_map_lock);
+            } else {
+                r = qemu_vfio_dma_reset_temporary(s->vfio);
+                if (r) {
+                    goto fail;
+                }
+            }
+            goto try_map;
+        }
+        if (r) {
+            goto fail;
+        }
+
+        for (j = 0; j < qiov->iov[i].iov_len / s->page_size; j++) {
+            pagelist[entries++] = iova + j * s->page_size;
+        }
+        trace_nvme_cmd_map_qiov_iov(s, i, qiov->iov[i].iov_base,
+                                    qiov->iov[i].iov_len / s->page_size);
+    }
+
+    s->dma_map_count += qiov->size;
+
+    assert(entries <= s->page_size / sizeof(uint64_t));
+    switch (entries) {
+    case 0:
+        abort();
+    case 1:
+        cmd->prp1 = cpu_to_le64(pagelist[0]);
+        cmd->prp2 = 0;
+        break;
+    case 2:
+        cmd->prp1 = cpu_to_le64(pagelist[0]);
+        cmd->prp2 = cpu_to_le64(pagelist[1]);;
+        break;
+    default:
+        cmd->prp1 = cpu_to_le64(pagelist[0]);
+        cmd->prp2 = cpu_to_le64(req->prp_list_iova);
+        for (i = 0; i < entries - 1; ++i) {
+            pagelist[i] = cpu_to_le64(pagelist[i + 1]);
+        }
+        pagelist[entries - 1] = 0;
+        break;
+    }
+    trace_nvme_cmd_map_qiov(s, cmd, req, qiov, entries);
+    for (i = 0; i < entries; ++i) {
+        trace_nvme_cmd_map_qiov_pages(s, i, pagelist[i]);
+    }
+    return 0;
+fail:
+    /* No need to unmap [0 - i) iovs even if we've failed, since we don't
+     * increment s->dma_map_count. This is okay for fixed mapping memory areas
+     * because they are already mapped before calling this function; for
+     * temporary mappings, a later nvme_cmd_(un)map_qiov will reclaim by
+     * calling qemu_vfio_dma_reset_temporary when necessary. */
+    return r;
+}
+
+typedef struct {
+    Coroutine *co;
+    int ret;
+    AioContext *ctx;
+} NVMeCoData;
+
+static void nvme_rw_cb_bh(void *opaque)
+{
+    NVMeCoData *data = opaque;
+    qemu_coroutine_enter(data->co);
+}
+
+static void nvme_rw_cb(void *opaque, int ret)
+{
+    NVMeCoData *data = opaque;
+    data->ret = ret;
+    if (!data->co) {
+        /* The rw coroutine hasn't yielded, don't try to enter. */
+        return;
+    }
+    aio_bh_schedule_oneshot(data->ctx, nvme_rw_cb_bh, data);
+}
+
+static coroutine_fn int nvme_co_prw_aligned(BlockDriverState *bs,
+                                            uint64_t offset, uint64_t bytes,
+                                            QEMUIOVector *qiov,
+                                            bool is_write,
+                                            int flags)
+{
+    int r;
+    BDRVNVMeState *s = bs->opaque;
+    NVMeQueuePair *ioq = s->queues[1];
+    NVMeRequest *req;
+    uint32_t cdw12 = (((bytes >> BDRV_SECTOR_BITS) - 1) & 0xFFFF) |
+                       (flags & BDRV_REQ_FUA ? 1 << 30 : 0);
+    NvmeCmd cmd = {
+        .opcode = is_write ? NVME_CMD_WRITE : NVME_CMD_READ,
+        .nsid = cpu_to_le32(s->nsid),
+        .cdw10 = cpu_to_le32((offset >> BDRV_SECTOR_BITS) & 0xFFFFFFFF),
+        .cdw11 = cpu_to_le32(((offset >> BDRV_SECTOR_BITS) >> 32) & 0xFFFFFFFF),
+        .cdw12 = cpu_to_le32(cdw12),
+    };
+    NVMeCoData data = {
+        .ctx = bdrv_get_aio_context(bs),
+        .ret = -EINPROGRESS,
+    };
+
+    trace_nvme_prw_aligned(s, is_write, offset, bytes, flags, qiov->niov);
+    assert(s->nr_queues > 1);
+    req = nvme_get_free_req(ioq);
+    assert(req);
+
+    qemu_co_mutex_lock(&s->dma_map_lock);
+    r = nvme_cmd_map_qiov(bs, &cmd, req, qiov);
+    qemu_co_mutex_unlock(&s->dma_map_lock);
+    if (r) {
+        req->busy = false;
+        return r;
+    }
+    nvme_submit_command(s, ioq, req, &cmd, nvme_rw_cb, &data);
+
+    data.co = qemu_coroutine_self();
+    while (data.ret == -EINPROGRESS) {
+        qemu_coroutine_yield();
+    }
+
+    qemu_co_mutex_lock(&s->dma_map_lock);
+    r = nvme_cmd_unmap_qiov(bs, qiov);
+    qemu_co_mutex_unlock(&s->dma_map_lock);
+    if (r) {
+        return r;
+    }
+
+    trace_nvme_rw_done(s, is_write, offset, bytes, data.ret);
+    return data.ret;
+}
+
+static inline bool nvme_qiov_aligned(BlockDriverState *bs,
+                                     const QEMUIOVector *qiov)
+{
+    int i;
+    BDRVNVMeState *s = bs->opaque;
+
+    for (i = 0; i < qiov->niov; ++i) {
+        if (!QEMU_PTR_IS_ALIGNED(qiov->iov[i].iov_base, s->page_size) ||
+            !QEMU_IS_ALIGNED(qiov->iov[i].iov_len, s->page_size)) {
+            trace_nvme_qiov_unaligned(qiov, i, qiov->iov[i].iov_base,
+                                      qiov->iov[i].iov_len, s->page_size);
+            return false;
+        }
+    }
+    return true;
+}
+
+static int nvme_co_prw(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
+                       QEMUIOVector *qiov, bool is_write, int flags)
+{
+    BDRVNVMeState *s = bs->opaque;
+    int r;
+    uint8_t *buf = NULL;
+    QEMUIOVector local_qiov;
+
+    assert(QEMU_IS_ALIGNED(offset, s->page_size));
+    assert(QEMU_IS_ALIGNED(bytes, s->page_size));
+    assert(bytes <= s->max_transfer);
+    if (nvme_qiov_aligned(bs, qiov)) {
+        return nvme_co_prw_aligned(bs, offset, bytes, qiov, is_write, flags);
+    }
+    trace_nvme_prw_buffered(s, offset, bytes, qiov->niov, is_write);
+    buf = qemu_try_blockalign(bs, bytes);
+
+    if (!buf) {
+        return -ENOMEM;
+    }
+    qemu_iovec_init(&local_qiov, 1);
+    if (is_write) {
+        qemu_iovec_to_buf(qiov, 0, buf, bytes);
+    }
+    qemu_iovec_add(&local_qiov, buf, bytes);
+    r = nvme_co_prw_aligned(bs, offset, bytes, &local_qiov, is_write, flags);
+    qemu_iovec_destroy(&local_qiov);
+    if (!r && !is_write) {
+        qemu_iovec_from_buf(qiov, 0, buf, bytes);
+    }
+    qemu_vfree(buf);
+    return r;
+}
+
+static coroutine_fn int nvme_co_preadv(BlockDriverState *bs,
+                                       uint64_t offset, uint64_t bytes,
+                                       QEMUIOVector *qiov, int flags)
+{
+    return nvme_co_prw(bs, offset, bytes, qiov, false, flags);
+}
+
+static coroutine_fn int nvme_co_pwritev(BlockDriverState *bs,
+                                        uint64_t offset, uint64_t bytes,
+                                        QEMUIOVector *qiov, int flags)
+{
+    return nvme_co_prw(bs, offset, bytes, qiov, true, flags);
+}
+
+static coroutine_fn int nvme_co_flush(BlockDriverState *bs)
+{
+    BDRVNVMeState *s = bs->opaque;
+    NVMeQueuePair *ioq = s->queues[1];
+    NVMeRequest *req;
+    NvmeCmd cmd = {
+        .opcode = NVME_CMD_FLUSH,
+        .nsid = cpu_to_le32(s->nsid),
+    };
+    NVMeCoData data = {
+        .ctx = bdrv_get_aio_context(bs),
+        .ret = -EINPROGRESS,
+    };
+
+    assert(s->nr_queues > 1);
+    req = nvme_get_free_req(ioq);
+    assert(req);
+    nvme_submit_command(s, ioq, req, &cmd, nvme_rw_cb, &data);
+
+    data.co = qemu_coroutine_self();
+    if (data.ret == -EINPROGRESS) {
+        qemu_coroutine_yield();
+    }
+
+    return data.ret;
+}
+
+
+static int nvme_reopen_prepare(BDRVReopenState *reopen_state,
+                               BlockReopenQueue *queue, Error **errp)
+{
+    return 0;
+}
+
+static int64_t coroutine_fn nvme_co_get_block_status(BlockDriverState *bs,
+                                                     int64_t sector_num,
+                                                     int nb_sectors, int *pnum,
+                                                     BlockDriverState **file)
+{
+    *pnum = nb_sectors;
+    *file = bs;
+
+    return BDRV_BLOCK_ALLOCATED | BDRV_BLOCK_OFFSET_VALID |
+           (sector_num << BDRV_SECTOR_BITS);
+}
+
+static void nvme_refresh_filename(BlockDriverState *bs, QDict *opts)
+{
+    QINCREF(opts);
+    qdict_del(opts, "filename");
+
+    if (!qdict_size(opts)) {
+        snprintf(bs->exact_filename, sizeof(bs->exact_filename), "%s://",
+                 bs->drv->format_name);
+    }
+
+    qdict_put(opts, "driver", qstring_from_str(bs->drv->format_name));
+    bs->full_open_options = opts;
+}
+
+static void nvme_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    bs->bl.opt_mem_alignment = s->page_size;
+    bs->bl.request_alignment = s->page_size;
+    bs->bl.max_transfer = s->max_transfer;
+}
+
+static void nvme_detach_aio_context(BlockDriverState *bs)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+                           false, NULL, NULL);
+}
+
+static void nvme_attach_aio_context(BlockDriverState *bs,
+                                    AioContext *new_context)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    s->aio_context = new_context;
+    aio_set_event_notifier(new_context, &s->irq_notifier,
+                           false, nvme_handle_event, nvme_poll_cb);
+}
+
+static void nvme_aio_plug(BlockDriverState *bs)
+{
+    BDRVNVMeState *s = bs->opaque;
+    s->plugged++;
+}
+
+static void nvme_aio_unplug(BlockDriverState *bs)
+{
+    int i;
+    BDRVNVMeState *s = bs->opaque;
+    assert(s->plugged);
+    if (!--s->plugged) {
+        for (i = 1; i < s->nr_queues; i++) {
+            NVMeQueuePair *q = s->queues[i];
+            qemu_mutex_lock(&q->lock);
+            nvme_kick(s, q);
+            nvme_process_completion(s, q);
+            qemu_mutex_unlock(&q->lock);
+        }
+    }
+}
+
+static void nvme_register_buf(BlockDriverState *bs, void *host, size_t size)
+{
+    int ret;
+    BDRVNVMeState *s = bs->opaque;
+
+    ret = qemu_vfio_dma_map(s->vfio, host, size, false, NULL);
+    if (ret) {
+        /* FIXME: we may run out of IOVA addresses after repeated
+         * bdrv_register_buf/bdrv_unregister_buf, because nvme_vfio_dma_unmap
+         * doesn't reclaim addresses for fixed mappings. */
+        error_report("nvme_register_buf failed: %s", strerror(-ret));
+    }
+}
+
+static void nvme_unregister_buf(BlockDriverState *bs, void *host)
+{
+    BDRVNVMeState *s = bs->opaque;
+
+    qemu_vfio_dma_unmap(s->vfio, host);
+}
+
+static BlockDriver bdrv_nvme = {
+    .format_name              = "nvme",
+    .protocol_name            = "nvme",
+    .instance_size            = sizeof(BDRVNVMeState),
+
+    .bdrv_parse_filename      = nvme_parse_filename,
+    .bdrv_file_open           = nvme_file_open,
+    .bdrv_close               = nvme_close,
+    .bdrv_getlength           = nvme_getlength,
+
+    .bdrv_co_preadv           = nvme_co_preadv,
+    .bdrv_co_pwritev          = nvme_co_pwritev,
+    .bdrv_co_flush_to_disk    = nvme_co_flush,
+    .bdrv_reopen_prepare      = nvme_reopen_prepare,
+
+    .bdrv_co_get_block_status = nvme_co_get_block_status,
+
+    .bdrv_refresh_filename    = nvme_refresh_filename,
+    .bdrv_refresh_limits      = nvme_refresh_limits,
+
+    .bdrv_detach_aio_context  = nvme_detach_aio_context,
+    .bdrv_attach_aio_context  = nvme_attach_aio_context,
+
+    .bdrv_io_plug             = nvme_aio_plug,
+    .bdrv_io_unplug           = nvme_aio_unplug,
+
+    .bdrv_register_buf        = nvme_register_buf,
+    .bdrv_unregister_buf      = nvme_unregister_buf,
+};
+
+static void bdrv_nvme_init(void)
+{
+    bdrv_register(&bdrv_nvme);
+}
+
+block_init(bdrv_nvme_init);
diff --git a/block/trace-events b/block/trace-events
index 11c8d5f..02dd80f 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -124,3 +124,24 @@ vxhs_open_iio_open(const char *host) "Failed to connect to storage agent on host
 vxhs_parse_uri_hostinfo(char *host, int port) "Host: IP %s, Port %d"
 vxhs_close(char *vdisk_guid) "Closing vdisk %s"
 vxhs_get_creds(const char *cacert, const char *client_key, const char *client_cert) "cacert %s, client_key %s, client_cert %s"
+
+# block/nvme.c
+nvme_kick(void *s, int queue) "s %p queue %d"
+nvme_dma_flush_queue_wait(void *s) "s %p"
+nvme_error(int cmd_specific, int sq_head, int sqid, int cid, int status) "cmd_specific %d sq_head %d sqid %d cid %d status 0x%x"
+nvme_process_completion(void *s, int index, int inflight) "s %p queue %d inflight %d"
+nvme_process_completion_queue_busy(void *s, int index) "s %p queue %d"
+nvme_complete_command(void *s, int index, int cid) "s %p queue %d cid %d"
+nvme_submit_command(void *s, int index, int cid) "s %p queue %d cid %d"
+nvme_submit_command_raw(int c0, int c1, int c2, int c3, int c4, int c5, int c6, int c7) "%02x %02x %02x %02x %02x %02x %02x %02x"
+nvme_handle_event(void *s) "s %p"
+nvme_poll_cb(void *s) "s %p"
+nvme_prw_aligned(void *s, int is_write, uint64_t offset, uint64_t bytes, int flags, int niov) "s %p is_write %d offset %"PRId64" bytes %"PRId64" flags %d niov %d"
+nvme_qiov_unaligned(const void *qiov, int n, void *base, size_t size, int align) "qiov %p n %d base %p size 0x%zx align 0x%x"
+nvme_prw_buffered(void *s, uint64_t offset, uint64_t bytes, int niov, int is_write) "s %p offset %"PRId64" bytes %"PRId64" niov %d is_write %d"
+nvme_rw_done(void *s, int is_write, uint64_t offset, uint64_t bytes, int ret) "s %p is_write %d offset %"PRId64" bytes %"PRId64" ret %d"
+nvme_dma_map_flush(void *s) "s %p"
+nvme_free_req_queue_wait(void *q) "q %p"
+nvme_cmd_map_qiov(void *s, void *cmd, void *req, void *qiov, int entries) "s %p cmd %p req %p qiov %p entries %d"
+nvme_cmd_map_qiov_pages(void *s, int i, uint64_t page) "s %p page[%d] 0x%"PRIx64
+nvme_cmd_map_qiov_iov(void *s, int i, void *page, int pages) "s %p iov[%d] %p pages %d"
diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
new file mode 100644
index 0000000..0ca1a2d
--- /dev/null
+++ b/docs/devel/testing.rst
@@ -0,0 +1,486 @@
+===============
+Testing in QEMU
+===============
+
+This document describes the testing infrastructure in QEMU.
+
+Testing with "make check"
+=========================
+
+The "make check" testing family includes most of the C based tests in QEMU. For
+a quick help, run ``make check-help`` from the source tree.
+
+The usual way to run these tests is:
+
+.. code::
+
+  make check
+
+which includes QAPI schema tests, unit tests, and QTests. Different sub-types
+of "make check" tests will be explained below.
+
+Before running tests, it is best to build QEMU programs first. Some tests
+expect the executables to exist and will fail with obscure messages if they
+cannot find them.
+
+Unit tests
+----------
+
+Unit tests, which can be invoked with ``make check-unit``, are simple C tests
+that typically link to individual QEMU object files and exercise them by
+calling exported functions.
+
+If you are writing new code in QEMU, consider adding a unit test, especially
+for utility modules that are relatively stateless or have few dependencies. To
+add a new unit test:
+
+1. Create a new source file. For example, ``tests/foo-test.c``.
+
+2. Write the test. Normally you would include the header file which exports
+   the module API, then verify the interface behaves as expected from your
+   test. The test code should be organized with the glib testing framework.
+   Copying and modifying an existing test is usually a good idea.
+
+3. Add the test to ``tests/Makefile.include``. First, name the unit test
+   program and add it to ``$(check-unit-y)``; then add a rule to build the
+   executable. Optionally, you can add a magical variable to support ``gcov``.
+   For example:
+
+.. code::
+
+  check-unit-y += tests/foo-test$(EXESUF)
+  tests/foo-test$(EXESUF): tests/foo-test.o $(test-util-obj-y)
+  ...
+  gcov-files-foo-test-y = util/foo.c
+
+Since unit tests don't require environment variables, the simplest way to debug
+a unit test failure is often directly invoking it or even running it under
+``gdb``. However there can still be differences in behavior between ``make``
+invocations and your manual run, due to ``$MALLOC_PERTURB_`` environment
+variable (which affects memory reclamation and catches invalid pointers better)
+and gtester options. If necessary, you can run
+
+.. code::
+  make check-unit V=1
+
+and copy the actual command line which executes the unit test, then run
+it from the command line.
+
+QTest
+-----
+
+QTest is a device emulation testing framework.  It can be very useful to test
+device models; it could also control certain aspects of QEMU (such as virtual
+clock stepping), with a special purpose "qtest" protocol.  Refer to the
+documentation in ``qtest.c`` for more details of the protocol.
+
+QTest cases can be executed with
+
+.. code::
+
+   make check-qtest
+
+The QTest library is implemented by ``tests/libqtest.c`` and the API is defined
+in ``tests/libqtest.h``.
+
+Consider adding a new QTest case when you are introducing a new virtual
+hardware, or extending one if you are adding functionalities to an existing
+virtual device.
+
+On top of libqtest, a higher level library, ``libqos``, was created to
+encapsulate common tasks of device drivers, such as memory management and
+communicating with system buses or devices. Many virtual device tests use
+libqos instead of directly calling into libqtest.
+
+Steps to add a new QTest case are:
+
+1. Create a new source file for the test. (More than one file can be added as
+   necessary.) For example, ``tests/test-foo-device.c``.
+
+2. Write the test code with the glib and libqtest/libqos API. See also existing
+   tests and the library headers for reference.
+
+3. Register the new test in ``tests/Makefile.include``. Add the test executable
+   name to an appropriate ``check-qtest-*-y`` variable. For example:
+
+   ``check-qtest-generic-y = tests/test-foo-device$(EXESUF)``
+
+4. Add object dependencies of the executable in the Makefile, including the
+   test source file(s) and other interesting objects. For example:
+
+   ``tests/test-foo-device$(EXESUF): tests/test-foo-device.o $(libqos-obj-y)``
+
+Debugging a QTest failure is slightly harder than the unit test because the
+tests look up QEMU program names in the environment variables, such as
+``QTEST_QEMU_BINARY`` and ``QTEST_QEMU_IMG``, and also because it is not easy
+to attach gdb to the QEMU process spawned from the test. But manual invoking
+and using gdb on the test is still simple to do: find out the actual command
+from the output of
+
+.. code::
+  make check-qtest V=1
+
+which you can run manually.
+
+QAPI schema tests
+-----------------
+
+The QAPI schema tests validate the QAPI parser used by QMP, by feeding
+predefined input to the parser and comparing the result with the reference
+output.
+
+The input/output data is managed under the ``tests/qapi-schema`` directory.
+Each test case includes four files that have a common base name:
+
+  * ``${casename}.json`` - the file contains the JSON input for feeding the
+    parser
+  * ``${casename}.out`` - the file contains the expected stdout from the parser
+  * ``${casename}.err`` - the file contains the expected stderr from the parser
+  * ``${casename}.exit`` - the expected error code
+
+Consider adding a new QAPI schema test when you are making a change on the QAPI
+parser (either fixing a bug or extending/modifying the syntax). To do this:
+
+1. Add four files for the new case as explained above. For example:
+
+  ``$EDITOR tests/qapi-schema/foo.{json,out,err,exit}``.
+
+2. Add the new test in ``tests/Makefile.include``. For example:
+
+  ``qapi-schema += foo.json``
+
+check-block
+-----------
+
+``make check-block`` is a legacy command to invoke block layer iotests and is
+rarely used. See "QEMU iotests" section below for more information.
+
+GCC gcov support
+----------------
+
+``gcov`` is a GCC tool to analyze the testing coverage by instrumenting the
+tested code. To use it, configure QEMU with ``--enable-gcov`` option and build.
+Then run ``make check`` as usual. There will be additional ``gcov`` output as
+the testing goes on, showing the test coverage percentage numbers per analyzed
+source file. More detailed reports can be obtained by running ``gcov`` command
+on the output files under ``$build_dir/tests/``, please read the ``gcov``
+documentation for more information.
+
+QEMU iotests
+============
+
+QEMU iotests, under the directory ``tests/qemu-iotests``, is the testing
+framework widely used to test block layer related features. It is higher level
+than "make check" tests and 99% of the code is written in bash or Python
+scripts.  The testing success criteria is golden output comparison, and the
+test files are named with numbers.
+
+To run iotests, make sure QEMU is built successfully, then switch to the
+``tests/qemu-iotests`` directory under the build directory, and run ``./check``
+with desired arguments from there.
+
+By default, "raw" format and "file" protocol is used; all tests will be
+executed, except the unsupported ones. You can override the format and protocol
+with arguments:
+
+.. code::
+
+  # test with qcow2 format
+  ./check -qcow2
+  # or test a different protocol
+  ./check -nbd
+
+It's also possible to list test numbers explicitly:
+
+.. code::
+
+  # run selected cases with qcow2 format
+  ./check -qcow2 001 030 153
+
+Cache mode can be selected with the "-c" option, which may help reveal bugs
+that are specific to certain cache mode.
+
+More options are supported by the ``./check`` script, run ``./check -h`` for
+help.
+
+Writing a new test case
+-----------------------
+
+Consider writing a tests case when you are making any changes to the block
+layer. An iotest case is usually the choice for that. There are already many
+test cases, so it is possible that extending one of them may achieve the goal
+and save the boilerplate to create one.  (Unfortunately, there isn't a 100%
+reliable way to find a related one out of hundreds of tests.  One approach is
+using ``git grep``.)
+
+Usually an iotest case consists of two files. One is an executable that
+produces output to stdout and stderr, the other is the expected reference
+output. They are given the same number in file names. E.g. Test script ``055``
+and reference output ``055.out``.
+
+In rare cases, when outputs differ between cache mode ``none`` and others, a
+``.out.nocache`` file is added. In other cases, when outputs differ between
+image formats, more than one ``.out`` files are created ending with the
+respective format names, e.g. ``178.out.qcow2`` and ``178.out.raw``.
+
+There isn't a hard rule about how to write a test script, but a new test is
+usually a (copy and) modification of an existing case.  There are a few
+commonly used ways to create a test:
+
+* A Bash script. It will make use of several environmental variables related
+  to the testing procedure, and could source a group of ``common.*`` libraries
+  for some common helper routines.
+
+* A Python unittest script. Import ``iotests`` and create a subclass of
+  ``iotests.QMPTestCase``, then call ``iotests.main`` method. The downside of
+  this approach is that the output is too scarce, and the script is considered
+  harder to debug.
+
+* A simple Python script without using unittest module. This could also import
+  ``iotests`` for launching QEMU and utilities etc, but it doesn't inherit
+  from ``iotests.QMPTestCase`` therefore doesn't use the Python unittest
+  execution. This is a combination of 1 and 2.
+
+Pick the language per your preference since both Bash and Python have
+comparable library support for invoking and interacting with QEMU programs. If
+you opt for Python, it is strongly recommended to write Python 3 compatible
+code.
+
+Docker based tests
+==================
+
+Introduction
+------------
+
+The Docker testing framework in QEMU utilizes public Docker images to build and
+test QEMU in predefined and widely accessible Linux environments.  This makes
+it possible to expand the test coverage across distros, toolchain flavors and
+library versions.
+
+Prerequisites
+-------------
+
+Install "docker" with the system package manager and start the Docker service
+on your development machine, then make sure you have the privilege to run
+Docker commands. Typically it means setting up passwordless ``sudo docker``
+command or login as root. For example:
+
+.. code::
+
+  $ sudo yum install docker
+  $ # or `apt-get install docker` for Ubuntu, etc.
+  $ sudo systemctl start docker
+  $ sudo docker ps
+
+The last command should print an empty table, to verify the system is ready.
+
+An alternative method to set up permissions is by adding the current user to
+"docker" group and making the docker daemon socket file (by default
+``/var/run/docker.sock``) accessible to the group:
+
+.. code::
+
+  $ sudo groupadd docker
+  $ sudo usermod $USER -G docker
+  $ sudo chown :docker /var/run/docker.sock
+
+Note that any one of above configurations makes it possible for the user to
+exploit the whole host with Docker bind mounting or other privileged
+operations.  So only do it on development machines.
+
+Quickstart
+----------
+
+From source tree, type ``make docker`` to see the help. Testing can be started
+without configuring or building QEMU (``configure`` and ``make`` are done in
+the container, with parameters defined by the make target):
+
+.. code::
+
+  make docker-test-build@min-glib
+
+This will create a container instance using the ``min-glib`` image (the image
+is downloaded and initialized automatically), in which the ``test-build`` job
+is executed.
+
+Images
+------
+
+Along with many other images, the ``min-glib`` image is defined in a Dockerfile
+in ``tests/docker/dockefiles/``, called ``min-glib.docker``. ``make docker``
+command will list all the available images.
+
+To add a new image, simply create a new ``.docker`` file under the
+``tests/docker/dockerfiles/`` directory.
+
+A ``.pre`` script can be added beside the ``.docker`` file, which will be
+executed before building the image under the build context directory. This is
+mainly used to do necessary host side setup. One such setup is ``binfmt_misc``,
+for example, to make qemu-user powered cross build containers work.
+
+Tests
+-----
+
+Different tests are added to cover various configurations to build and test
+QEMU.  Docker tests are the executables under ``tests/docker`` named
+``test-*``. They are typically shell scripts and are built on top of a shell
+library, ``tests/docker/common.rc``, which provides helpers to find the QEMU
+source and build it.
+
+The full list of tests is printed in the ``make docker`` help.
+
+Tools
+-----
+
+There are executables that are created to run in a specific Docker environment.
+This makes it easy to write scripts that have heavy or special dependencies,
+but are still very easy to use.
+
+Currently the only tool is ``travis``, which mimics the Travis-CI tests in a
+container. It runs in the ``travis`` image:
+
+.. code::
+
+  make docker-travis@travis
+
+Debugging a Docker test failure
+-------------------------------
+
+When CI tasks, maintainers or yourself report a Docker test failure, follow the
+below steps to debug it:
+
+1. Locally reproduce the failure with the reported command line. E.g. run
+   ``make docker-test-mingw@fedora J=8``.
+2. Add "V=1" to the command line, try again, to see the verbose output.
+3. Further add "DEBUG=1" to the command line. This will pause in a shell prompt
+   in the container right before testing starts. You could either manually
+   build QEMU and run tests from there, or press Ctrl-D to let the Docker
+   testing continue.
+4. If you press Ctrl-D, the same building and testing procedure will begin, and
+   will hopefully run into the error again. After that, you will be dropped to
+   the prompt for debug.
+
+Options
+-------
+
+Various options can be used to affect how Docker tests are done. The full
+list is in the ``make docker`` help text. The frequently used ones are:
+
+* ``V=1``: the same as in top level ``make``. It will be propagated to the
+  container and enable verbose output.
+* ``J=$N``: the number of parallel tasks in make commands in the container,
+  similar to the ``-j $N`` option in top level ``make``. (The ``-j`` option in
+  top level ``make`` will not be propagated into the container.)
+* ``DEBUG=1``: enables debug. See the previous "Debugging a Docker test
+  failure" section.
+
+VM testing
+==========
+
+This test suite contains scripts that bootstrap various guest images that have
+necessary packages to build QEMU. The basic usage is documented in ``Makefile``
+help which is displayed with ``make vm-test``.
+
+Quickstart
+----------
+
+Run ``make vm-test`` to list available make targets. Invoke a specific make
+command to run build test in an image. For example, ``make vm-build-freebsd``
+will build the source tree in the FreeBSD image. The command can be executed
+from either the source tree or the build dir; if the former, ``./configure`` is
+not needed. The command will then generate the test image in ``./tests/vm/``
+under the working directory.
+
+Note: images created by the scripts accept a well-known RSA key pair for SSH
+access, so they SHOULD NOT be exposed to external interfaces if you are
+concerned about attackers taking control of the guest and potentially
+exploiting a QEMU security bug to compromise the host.
+
+QEMU binary
+-----------
+
+By default, qemu-system-x86_64 is searched in $PATH to run the guest. If there
+isn't one, or if it is older than 2.10, the test won't work. In this case,
+provide the QEMU binary in env var: ``QEMU=/path/to/qemu-2.10+``.
+
+Make jobs
+---------
+
+The ``-j$X`` option in the make command line is not propagated into the VM,
+specify ``J=$X`` to control the make jobs in the guest.
+
+Debugging
+---------
+
+Add ``DEBUG=1`` and/or ``V=1`` to the make command to allow interactive
+debugging and verbose output. If this is not enough, see the next section.
+
+Manual invocation
+-----------------
+
+Each guest script is an executable script with the same command line options.
+For example to work with the netbsd guest, use ``$QEMU_SRC/tests/vm/netbsd``:
+
+.. code::
+
+    $ cd $QEMU_SRC/tests/vm
+
+    # To bootstrap the image
+    $ ./netbsd --build-image --image /var/tmp/netbsd.img
+    <...>
+
+    # To run an arbitrary command in guest (the output will not be echoed unless
+    # --debug is added)
+    $ ./netbsd --debug --image /var/tmp/netbsd.img uname -a
+
+    # To build QEMU in guest
+    $ ./netbsd --debug --image /var/tmp/netbsd.img --build-qemu $QEMU_SRC
+
+    # To get to an interactive shell
+    $ ./netbsd --interactive --image /var/tmp/netbsd.img sh
+
+Adding new guests
+-----------------
+
+Please look at existing guest scripts for how to add new guests.
+
+Most importantly, create a subclass of BaseVM and implement ``build_image()``
+method and define ``BUILD_SCRIPT``, then finally call ``basevm.main()`` from
+the script's ``main()``.
+
+* Usually in ``build_image()``, a template image is downloaded from a
+  predefined URL. ``BaseVM._download_with_cache()`` takes care of the cache and
+  the checksum, so consider using it.
+
+* Once the image is downloaded, users, SSH server and QEMU build deps should
+  be set up:
+
+  - Root password set to ``BaseVM.ROOT_PASS``
+  - User ``BaseVM.GUEST_USER`` is created, and password set to
+    ``BaseVM.GUEST_PASS``
+  - SSH service is enabled and started on boot,
+    ``$QEMU_SRC/tests/keys/id_rsa.pub`` is added to ssh's ``authorized_keys``
+    file of both root and the normal user
+  - DHCP client service is enabled and started on boot, so that it can
+    automatically configure the virtio-net-pci NIC and communicate with QEMU
+    user net (10.0.2.2)
+  - Necessary packages are installed to untar the source tarball and build
+    QEMU
+
+* Write a proper ``BUILD_SCRIPT`` template, which should be a shell script that
+  untars a raw virtio-blk block device, which is the tarball data blob of the
+  QEMU source tree, then configure/build it. Running "make check" is also
+  recommended.
+
+Image fuzzer testing
+====================
+
+An image fuzzer was added to exercise format drivers. Currently only qcow2 is
+supported. To start the fuzzer, run
+
+.. code::
+
+  tests/image-fuzzer/runner.py -c '[["qemu-img", "info", "$test_img"]]' /tmp/test qcow2
+
+Alternatively, some command different from "qemu-img info" can be tested, by
+changing the ``-c`` option.
diff --git a/docs/qemu-block-drivers.texi b/docs/qemu-block-drivers.texi
index 503c184..cd74767 100644
--- a/docs/qemu-block-drivers.texi
+++ b/docs/qemu-block-drivers.texi
@@ -785,6 +785,43 @@ warning: ssh server @code{ssh.example.com:22} does not support fsync
 With sufficiently new versions of libssh2 and OpenSSH, @code{fsync} is
 supported.
 
+@node disk_images_nvme
+@subsection NVMe disk images
+
+NVM Express (NVMe) storage controllers can be accessed directly by a userspace
+driver in QEMU.  This bypasses the host kernel file system and block layers
+while retaining QEMU block layer functionalities, such as block jobs, I/O
+throttling, image formats, etc.  Disk I/O performance is typically higher than
+with @code{-drive file=/dev/sda} using either thread pool or linux-aio.
+
+The controller will be exclusively used by the QEMU process once started. To be
+able to share storage between multiple VMs and other applications on the host,
+please use the file based protocols.
+
+Before starting QEMU, bind the host NVMe controller to the host vfio-pci
+driver.  For example:
+
+@example
+# modprobe vfio-pci
+# lspci -n -s 0000:06:0d.0
+06:0d.0 0401: 1102:0002 (rev 08)
+# echo 0000:06:0d.0 > /sys/bus/pci/devices/0000:06:0d.0/driver/unbind
+# echo 1102 0002 > /sys/bus/pci/drivers/vfio-pci/new_id
+
+# qemu-system-x86_64 -drive file=nvme://@var{host}:@var{bus}:@var{slot}.@var{func}/@var{namespace}
+@end example
+
+Alternative syntax using properties:
+
+@example
+qemu-system-x86_64 -drive file.driver=nvme,file.device=@var{host}:@var{bus}:@var{slot}.@var{func},file.namespace=@var{namespace}
+@end example
+
+@var{host}:@var{bus}:@var{slot}.@var{func} is the NVMe controller's PCI device
+address on the host.
+
+@var{namespace} is the NVMe namespace number, starting from 1.
+
 @node disk_image_locking
 @subsection Disk image file locking
 
diff --git a/fsdev/qemu-fsdev-throttle.c b/fsdev/qemu-fsdev-throttle.c
index 49eebb5..1dc07fb 100644
--- a/fsdev/qemu-fsdev-throttle.c
+++ b/fsdev/qemu-fsdev-throttle.c
@@ -20,13 +20,13 @@
 static void fsdev_throttle_read_timer_cb(void *opaque)
 {
     FsThrottle *fst = opaque;
-    qemu_co_enter_next(&fst->throttled_reqs[false]);
+    qemu_co_enter_next(&fst->throttled_reqs[false], NULL);
 }
 
 static void fsdev_throttle_write_timer_cb(void *opaque)
 {
     FsThrottle *fst = opaque;
-    qemu_co_enter_next(&fst->throttled_reqs[true]);
+    qemu_co_enter_next(&fst->throttled_reqs[true], NULL);
 }
 
 void fsdev_throttle_parse_opts(QemuOpts *opts, FsThrottle *fst, Error **errp)
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 7b62dad..8f39811 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -1,703 +1,7 @@
 #ifndef HW_NVME_H
 #define HW_NVME_H
 #include "qemu/cutils.h"
-
-typedef struct NvmeBar {
-    uint64_t    cap;
-    uint32_t    vs;
-    uint32_t    intms;
-    uint32_t    intmc;
-    uint32_t    cc;
-    uint32_t    rsvd1;
-    uint32_t    csts;
-    uint32_t    nssrc;
-    uint32_t    aqa;
-    uint64_t    asq;
-    uint64_t    acq;
-    uint32_t    cmbloc;
-    uint32_t    cmbsz;
-} NvmeBar;
-
-enum NvmeCapShift {
-    CAP_MQES_SHIFT     = 0,
-    CAP_CQR_SHIFT      = 16,
-    CAP_AMS_SHIFT      = 17,
-    CAP_TO_SHIFT       = 24,
-    CAP_DSTRD_SHIFT    = 32,
-    CAP_NSSRS_SHIFT    = 33,
-    CAP_CSS_SHIFT      = 37,
-    CAP_MPSMIN_SHIFT   = 48,
-    CAP_MPSMAX_SHIFT   = 52,
-};
-
-enum NvmeCapMask {
-    CAP_MQES_MASK      = 0xffff,
-    CAP_CQR_MASK       = 0x1,
-    CAP_AMS_MASK       = 0x3,
-    CAP_TO_MASK        = 0xff,
-    CAP_DSTRD_MASK     = 0xf,
-    CAP_NSSRS_MASK     = 0x1,
-    CAP_CSS_MASK       = 0xff,
-    CAP_MPSMIN_MASK    = 0xf,
-    CAP_MPSMAX_MASK    = 0xf,
-};
-
-#define NVME_CAP_MQES(cap)  (((cap) >> CAP_MQES_SHIFT)   & CAP_MQES_MASK)
-#define NVME_CAP_CQR(cap)   (((cap) >> CAP_CQR_SHIFT)    & CAP_CQR_MASK)
-#define NVME_CAP_AMS(cap)   (((cap) >> CAP_AMS_SHIFT)    & CAP_AMS_MASK)
-#define NVME_CAP_TO(cap)    (((cap) >> CAP_TO_SHIFT)     & CAP_TO_MASK)
-#define NVME_CAP_DSTRD(cap) (((cap) >> CAP_DSTRD_SHIFT)  & CAP_DSTRD_MASK)
-#define NVME_CAP_NSSRS(cap) (((cap) >> CAP_NSSRS_SHIFT)  & CAP_NSSRS_MASK)
-#define NVME_CAP_CSS(cap)   (((cap) >> CAP_CSS_SHIFT)    & CAP_CSS_MASK)
-#define NVME_CAP_MPSMIN(cap)(((cap) >> CAP_MPSMIN_SHIFT) & CAP_MPSMIN_MASK)
-#define NVME_CAP_MPSMAX(cap)(((cap) >> CAP_MPSMAX_SHIFT) & CAP_MPSMAX_MASK)
-
-#define NVME_CAP_SET_MQES(cap, val)   (cap |= (uint64_t)(val & CAP_MQES_MASK)  \
-                                                           << CAP_MQES_SHIFT)
-#define NVME_CAP_SET_CQR(cap, val)    (cap |= (uint64_t)(val & CAP_CQR_MASK)   \
-                                                           << CAP_CQR_SHIFT)
-#define NVME_CAP_SET_AMS(cap, val)    (cap |= (uint64_t)(val & CAP_AMS_MASK)   \
-                                                           << CAP_AMS_SHIFT)
-#define NVME_CAP_SET_TO(cap, val)     (cap |= (uint64_t)(val & CAP_TO_MASK)    \
-                                                           << CAP_TO_SHIFT)
-#define NVME_CAP_SET_DSTRD(cap, val)  (cap |= (uint64_t)(val & CAP_DSTRD_MASK) \
-                                                           << CAP_DSTRD_SHIFT)
-#define NVME_CAP_SET_NSSRS(cap, val)  (cap |= (uint64_t)(val & CAP_NSSRS_MASK) \
-                                                           << CAP_NSSRS_SHIFT)
-#define NVME_CAP_SET_CSS(cap, val)    (cap |= (uint64_t)(val & CAP_CSS_MASK)   \
-                                                           << CAP_CSS_SHIFT)
-#define NVME_CAP_SET_MPSMIN(cap, val) (cap |= (uint64_t)(val & CAP_MPSMIN_MASK)\
-                                                           << CAP_MPSMIN_SHIFT)
-#define NVME_CAP_SET_MPSMAX(cap, val) (cap |= (uint64_t)(val & CAP_MPSMAX_MASK)\
-                                                            << CAP_MPSMAX_SHIFT)
-
-enum NvmeCcShift {
-    CC_EN_SHIFT     = 0,
-    CC_CSS_SHIFT    = 4,
-    CC_MPS_SHIFT    = 7,
-    CC_AMS_SHIFT    = 11,
-    CC_SHN_SHIFT    = 14,
-    CC_IOSQES_SHIFT = 16,
-    CC_IOCQES_SHIFT = 20,
-};
-
-enum NvmeCcMask {
-    CC_EN_MASK      = 0x1,
-    CC_CSS_MASK     = 0x7,
-    CC_MPS_MASK     = 0xf,
-    CC_AMS_MASK     = 0x7,
-    CC_SHN_MASK     = 0x3,
-    CC_IOSQES_MASK  = 0xf,
-    CC_IOCQES_MASK  = 0xf,
-};
-
-#define NVME_CC_EN(cc)     ((cc >> CC_EN_SHIFT)     & CC_EN_MASK)
-#define NVME_CC_CSS(cc)    ((cc >> CC_CSS_SHIFT)    & CC_CSS_MASK)
-#define NVME_CC_MPS(cc)    ((cc >> CC_MPS_SHIFT)    & CC_MPS_MASK)
-#define NVME_CC_AMS(cc)    ((cc >> CC_AMS_SHIFT)    & CC_AMS_MASK)
-#define NVME_CC_SHN(cc)    ((cc >> CC_SHN_SHIFT)    & CC_SHN_MASK)
-#define NVME_CC_IOSQES(cc) ((cc >> CC_IOSQES_SHIFT) & CC_IOSQES_MASK)
-#define NVME_CC_IOCQES(cc) ((cc >> CC_IOCQES_SHIFT) & CC_IOCQES_MASK)
-
-enum NvmeCstsShift {
-    CSTS_RDY_SHIFT      = 0,
-    CSTS_CFS_SHIFT      = 1,
-    CSTS_SHST_SHIFT     = 2,
-    CSTS_NSSRO_SHIFT    = 4,
-};
-
-enum NvmeCstsMask {
-    CSTS_RDY_MASK   = 0x1,
-    CSTS_CFS_MASK   = 0x1,
-    CSTS_SHST_MASK  = 0x3,
-    CSTS_NSSRO_MASK = 0x1,
-};
-
-enum NvmeCsts {
-    NVME_CSTS_READY         = 1 << CSTS_RDY_SHIFT,
-    NVME_CSTS_FAILED        = 1 << CSTS_CFS_SHIFT,
-    NVME_CSTS_SHST_NORMAL   = 0 << CSTS_SHST_SHIFT,
-    NVME_CSTS_SHST_PROGRESS = 1 << CSTS_SHST_SHIFT,
-    NVME_CSTS_SHST_COMPLETE = 2 << CSTS_SHST_SHIFT,
-    NVME_CSTS_NSSRO         = 1 << CSTS_NSSRO_SHIFT,
-};
-
-#define NVME_CSTS_RDY(csts)     ((csts >> CSTS_RDY_SHIFT)   & CSTS_RDY_MASK)
-#define NVME_CSTS_CFS(csts)     ((csts >> CSTS_CFS_SHIFT)   & CSTS_CFS_MASK)
-#define NVME_CSTS_SHST(csts)    ((csts >> CSTS_SHST_SHIFT)  & CSTS_SHST_MASK)
-#define NVME_CSTS_NSSRO(csts)   ((csts >> CSTS_NSSRO_SHIFT) & CSTS_NSSRO_MASK)
-
-enum NvmeAqaShift {
-    AQA_ASQS_SHIFT  = 0,
-    AQA_ACQS_SHIFT  = 16,
-};
-
-enum NvmeAqaMask {
-    AQA_ASQS_MASK   = 0xfff,
-    AQA_ACQS_MASK   = 0xfff,
-};
-
-#define NVME_AQA_ASQS(aqa) ((aqa >> AQA_ASQS_SHIFT) & AQA_ASQS_MASK)
-#define NVME_AQA_ACQS(aqa) ((aqa >> AQA_ACQS_SHIFT) & AQA_ACQS_MASK)
-
-enum NvmeCmblocShift {
-    CMBLOC_BIR_SHIFT  = 0,
-    CMBLOC_OFST_SHIFT = 12,
-};
-
-enum NvmeCmblocMask {
-    CMBLOC_BIR_MASK  = 0x7,
-    CMBLOC_OFST_MASK = 0xfffff,
-};
-
-#define NVME_CMBLOC_BIR(cmbloc) ((cmbloc >> CMBLOC_BIR_SHIFT)  & \
-                                 CMBLOC_BIR_MASK)
-#define NVME_CMBLOC_OFST(cmbloc)((cmbloc >> CMBLOC_OFST_SHIFT) & \
-                                 CMBLOC_OFST_MASK)
-
-#define NVME_CMBLOC_SET_BIR(cmbloc, val)  \
-    (cmbloc |= (uint64_t)(val & CMBLOC_BIR_MASK) << CMBLOC_BIR_SHIFT)
-#define NVME_CMBLOC_SET_OFST(cmbloc, val) \
-    (cmbloc |= (uint64_t)(val & CMBLOC_OFST_MASK) << CMBLOC_OFST_SHIFT)
-
-enum NvmeCmbszShift {
-    CMBSZ_SQS_SHIFT   = 0,
-    CMBSZ_CQS_SHIFT   = 1,
-    CMBSZ_LISTS_SHIFT = 2,
-    CMBSZ_RDS_SHIFT   = 3,
-    CMBSZ_WDS_SHIFT   = 4,
-    CMBSZ_SZU_SHIFT   = 8,
-    CMBSZ_SZ_SHIFT    = 12,
-};
-
-enum NvmeCmbszMask {
-    CMBSZ_SQS_MASK   = 0x1,
-    CMBSZ_CQS_MASK   = 0x1,
-    CMBSZ_LISTS_MASK = 0x1,
-    CMBSZ_RDS_MASK   = 0x1,
-    CMBSZ_WDS_MASK   = 0x1,
-    CMBSZ_SZU_MASK   = 0xf,
-    CMBSZ_SZ_MASK    = 0xfffff,
-};
-
-#define NVME_CMBSZ_SQS(cmbsz)  ((cmbsz >> CMBSZ_SQS_SHIFT)   & CMBSZ_SQS_MASK)
-#define NVME_CMBSZ_CQS(cmbsz)  ((cmbsz >> CMBSZ_CQS_SHIFT)   & CMBSZ_CQS_MASK)
-#define NVME_CMBSZ_LISTS(cmbsz)((cmbsz >> CMBSZ_LISTS_SHIFT) & CMBSZ_LISTS_MASK)
-#define NVME_CMBSZ_RDS(cmbsz)  ((cmbsz >> CMBSZ_RDS_SHIFT)   & CMBSZ_RDS_MASK)
-#define NVME_CMBSZ_WDS(cmbsz)  ((cmbsz >> CMBSZ_WDS_SHIFT)   & CMBSZ_WDS_MASK)
-#define NVME_CMBSZ_SZU(cmbsz)  ((cmbsz >> CMBSZ_SZU_SHIFT)   & CMBSZ_SZU_MASK)
-#define NVME_CMBSZ_SZ(cmbsz)   ((cmbsz >> CMBSZ_SZ_SHIFT)    & CMBSZ_SZ_MASK)
-
-#define NVME_CMBSZ_SET_SQS(cmbsz, val)   \
-    (cmbsz |= (uint64_t)(val &  CMBSZ_SQS_MASK)  << CMBSZ_SQS_SHIFT)
-#define NVME_CMBSZ_SET_CQS(cmbsz, val)   \
-    (cmbsz |= (uint64_t)(val & CMBSZ_CQS_MASK) << CMBSZ_CQS_SHIFT)
-#define NVME_CMBSZ_SET_LISTS(cmbsz, val) \
-    (cmbsz |= (uint64_t)(val & CMBSZ_LISTS_MASK) << CMBSZ_LISTS_SHIFT)
-#define NVME_CMBSZ_SET_RDS(cmbsz, val)   \
-    (cmbsz |= (uint64_t)(val & CMBSZ_RDS_MASK) << CMBSZ_RDS_SHIFT)
-#define NVME_CMBSZ_SET_WDS(cmbsz, val)   \
-    (cmbsz |= (uint64_t)(val & CMBSZ_WDS_MASK) << CMBSZ_WDS_SHIFT)
-#define NVME_CMBSZ_SET_SZU(cmbsz, val)   \
-    (cmbsz |= (uint64_t)(val & CMBSZ_SZU_MASK) << CMBSZ_SZU_SHIFT)
-#define NVME_CMBSZ_SET_SZ(cmbsz, val)    \
-    (cmbsz |= (uint64_t)(val & CMBSZ_SZ_MASK) << CMBSZ_SZ_SHIFT)
-
-#define NVME_CMBSZ_GETSIZE(cmbsz) \
-    (NVME_CMBSZ_SZ(cmbsz) * (1 << (12 + 4 * NVME_CMBSZ_SZU(cmbsz))))
-
-typedef struct NvmeCmd {
-    uint8_t     opcode;
-    uint8_t     fuse;
-    uint16_t    cid;
-    uint32_t    nsid;
-    uint64_t    res1;
-    uint64_t    mptr;
-    uint64_t    prp1;
-    uint64_t    prp2;
-    uint32_t    cdw10;
-    uint32_t    cdw11;
-    uint32_t    cdw12;
-    uint32_t    cdw13;
-    uint32_t    cdw14;
-    uint32_t    cdw15;
-} NvmeCmd;
-
-enum NvmeAdminCommands {
-    NVME_ADM_CMD_DELETE_SQ      = 0x00,
-    NVME_ADM_CMD_CREATE_SQ      = 0x01,
-    NVME_ADM_CMD_GET_LOG_PAGE   = 0x02,
-    NVME_ADM_CMD_DELETE_CQ      = 0x04,
-    NVME_ADM_CMD_CREATE_CQ      = 0x05,
-    NVME_ADM_CMD_IDENTIFY       = 0x06,
-    NVME_ADM_CMD_ABORT          = 0x08,
-    NVME_ADM_CMD_SET_FEATURES   = 0x09,
-    NVME_ADM_CMD_GET_FEATURES   = 0x0a,
-    NVME_ADM_CMD_ASYNC_EV_REQ   = 0x0c,
-    NVME_ADM_CMD_ACTIVATE_FW    = 0x10,
-    NVME_ADM_CMD_DOWNLOAD_FW    = 0x11,
-    NVME_ADM_CMD_FORMAT_NVM     = 0x80,
-    NVME_ADM_CMD_SECURITY_SEND  = 0x81,
-    NVME_ADM_CMD_SECURITY_RECV  = 0x82,
-};
-
-enum NvmeIoCommands {
-    NVME_CMD_FLUSH              = 0x00,
-    NVME_CMD_WRITE              = 0x01,
-    NVME_CMD_READ               = 0x02,
-    NVME_CMD_WRITE_UNCOR        = 0x04,
-    NVME_CMD_COMPARE            = 0x05,
-    NVME_CMD_WRITE_ZEROS        = 0x08,
-    NVME_CMD_DSM                = 0x09,
-};
-
-typedef struct NvmeDeleteQ {
-    uint8_t     opcode;
-    uint8_t     flags;
-    uint16_t    cid;
-    uint32_t    rsvd1[9];
-    uint16_t    qid;
-    uint16_t    rsvd10;
-    uint32_t    rsvd11[5];
-} NvmeDeleteQ;
-
-typedef struct NvmeCreateCq {
-    uint8_t     opcode;
-    uint8_t     flags;
-    uint16_t    cid;
-    uint32_t    rsvd1[5];
-    uint64_t    prp1;
-    uint64_t    rsvd8;
-    uint16_t    cqid;
-    uint16_t    qsize;
-    uint16_t    cq_flags;
-    uint16_t    irq_vector;
-    uint32_t    rsvd12[4];
-} NvmeCreateCq;
-
-#define NVME_CQ_FLAGS_PC(cq_flags)  (cq_flags & 0x1)
-#define NVME_CQ_FLAGS_IEN(cq_flags) ((cq_flags >> 1) & 0x1)
-
-typedef struct NvmeCreateSq {
-    uint8_t     opcode;
-    uint8_t     flags;
-    uint16_t    cid;
-    uint32_t    rsvd1[5];
-    uint64_t    prp1;
-    uint64_t    rsvd8;
-    uint16_t    sqid;
-    uint16_t    qsize;
-    uint16_t    sq_flags;
-    uint16_t    cqid;
-    uint32_t    rsvd12[4];
-} NvmeCreateSq;
-
-#define NVME_SQ_FLAGS_PC(sq_flags)      (sq_flags & 0x1)
-#define NVME_SQ_FLAGS_QPRIO(sq_flags)   ((sq_flags >> 1) & 0x3)
-
-enum NvmeQueueFlags {
-    NVME_Q_PC           = 1,
-    NVME_Q_PRIO_URGENT  = 0,
-    NVME_Q_PRIO_HIGH    = 1,
-    NVME_Q_PRIO_NORMAL  = 2,
-    NVME_Q_PRIO_LOW     = 3,
-};
-
-typedef struct NvmeIdentify {
-    uint8_t     opcode;
-    uint8_t     flags;
-    uint16_t    cid;
-    uint32_t    nsid;
-    uint64_t    rsvd2[2];
-    uint64_t    prp1;
-    uint64_t    prp2;
-    uint32_t    cns;
-    uint32_t    rsvd11[5];
-} NvmeIdentify;
-
-typedef struct NvmeRwCmd {
-    uint8_t     opcode;
-    uint8_t     flags;
-    uint16_t    cid;
-    uint32_t    nsid;
-    uint64_t    rsvd2;
-    uint64_t    mptr;
-    uint64_t    prp1;
-    uint64_t    prp2;
-    uint64_t    slba;
-    uint16_t    nlb;
-    uint16_t    control;
-    uint32_t    dsmgmt;
-    uint32_t    reftag;
-    uint16_t    apptag;
-    uint16_t    appmask;
-} NvmeRwCmd;
-
-enum {
-    NVME_RW_LR                  = 1 << 15,
-    NVME_RW_FUA                 = 1 << 14,
-    NVME_RW_DSM_FREQ_UNSPEC     = 0,
-    NVME_RW_DSM_FREQ_TYPICAL    = 1,
-    NVME_RW_DSM_FREQ_RARE       = 2,
-    NVME_RW_DSM_FREQ_READS      = 3,
-    NVME_RW_DSM_FREQ_WRITES     = 4,
-    NVME_RW_DSM_FREQ_RW         = 5,
-    NVME_RW_DSM_FREQ_ONCE       = 6,
-    NVME_RW_DSM_FREQ_PREFETCH   = 7,
-    NVME_RW_DSM_FREQ_TEMP       = 8,
-    NVME_RW_DSM_LATENCY_NONE    = 0 << 4,
-    NVME_RW_DSM_LATENCY_IDLE    = 1 << 4,
-    NVME_RW_DSM_LATENCY_NORM    = 2 << 4,
-    NVME_RW_DSM_LATENCY_LOW     = 3 << 4,
-    NVME_RW_DSM_SEQ_REQ         = 1 << 6,
-    NVME_RW_DSM_COMPRESSED      = 1 << 7,
-    NVME_RW_PRINFO_PRACT        = 1 << 13,
-    NVME_RW_PRINFO_PRCHK_GUARD  = 1 << 12,
-    NVME_RW_PRINFO_PRCHK_APP    = 1 << 11,
-    NVME_RW_PRINFO_PRCHK_REF    = 1 << 10,
-};
-
-typedef struct NvmeDsmCmd {
-    uint8_t     opcode;
-    uint8_t     flags;
-    uint16_t    cid;
-    uint32_t    nsid;
-    uint64_t    rsvd2[2];
-    uint64_t    prp1;
-    uint64_t    prp2;
-    uint32_t    nr;
-    uint32_t    attributes;
-    uint32_t    rsvd12[4];
-} NvmeDsmCmd;
-
-enum {
-    NVME_DSMGMT_IDR = 1 << 0,
-    NVME_DSMGMT_IDW = 1 << 1,
-    NVME_DSMGMT_AD  = 1 << 2,
-};
-
-typedef struct NvmeDsmRange {
-    uint32_t    cattr;
-    uint32_t    nlb;
-    uint64_t    slba;
-} NvmeDsmRange;
-
-enum NvmeAsyncEventRequest {
-    NVME_AER_TYPE_ERROR                     = 0,
-    NVME_AER_TYPE_SMART                     = 1,
-    NVME_AER_TYPE_IO_SPECIFIC               = 6,
-    NVME_AER_TYPE_VENDOR_SPECIFIC           = 7,
-    NVME_AER_INFO_ERR_INVALID_SQ            = 0,
-    NVME_AER_INFO_ERR_INVALID_DB            = 1,
-    NVME_AER_INFO_ERR_DIAG_FAIL             = 2,
-    NVME_AER_INFO_ERR_PERS_INTERNAL_ERR     = 3,
-    NVME_AER_INFO_ERR_TRANS_INTERNAL_ERR    = 4,
-    NVME_AER_INFO_ERR_FW_IMG_LOAD_ERR       = 5,
-    NVME_AER_INFO_SMART_RELIABILITY         = 0,
-    NVME_AER_INFO_SMART_TEMP_THRESH         = 1,
-    NVME_AER_INFO_SMART_SPARE_THRESH        = 2,
-};
-
-typedef struct NvmeAerResult {
-    uint8_t event_type;
-    uint8_t event_info;
-    uint8_t log_page;
-    uint8_t resv;
-} NvmeAerResult;
-
-typedef struct NvmeCqe {
-    uint32_t    result;
-    uint32_t    rsvd;
-    uint16_t    sq_head;
-    uint16_t    sq_id;
-    uint16_t    cid;
-    uint16_t    status;
-} NvmeCqe;
-
-enum NvmeStatusCodes {
-    NVME_SUCCESS                = 0x0000,
-    NVME_INVALID_OPCODE         = 0x0001,
-    NVME_INVALID_FIELD          = 0x0002,
-    NVME_CID_CONFLICT           = 0x0003,
-    NVME_DATA_TRAS_ERROR        = 0x0004,
-    NVME_POWER_LOSS_ABORT       = 0x0005,
-    NVME_INTERNAL_DEV_ERROR     = 0x0006,
-    NVME_CMD_ABORT_REQ          = 0x0007,
-    NVME_CMD_ABORT_SQ_DEL       = 0x0008,
-    NVME_CMD_ABORT_FAILED_FUSE  = 0x0009,
-    NVME_CMD_ABORT_MISSING_FUSE = 0x000a,
-    NVME_INVALID_NSID           = 0x000b,
-    NVME_CMD_SEQ_ERROR          = 0x000c,
-    NVME_LBA_RANGE              = 0x0080,
-    NVME_CAP_EXCEEDED           = 0x0081,
-    NVME_NS_NOT_READY           = 0x0082,
-    NVME_NS_RESV_CONFLICT       = 0x0083,
-    NVME_INVALID_CQID           = 0x0100,
-    NVME_INVALID_QID            = 0x0101,
-    NVME_MAX_QSIZE_EXCEEDED     = 0x0102,
-    NVME_ACL_EXCEEDED           = 0x0103,
-    NVME_RESERVED               = 0x0104,
-    NVME_AER_LIMIT_EXCEEDED     = 0x0105,
-    NVME_INVALID_FW_SLOT        = 0x0106,
-    NVME_INVALID_FW_IMAGE       = 0x0107,
-    NVME_INVALID_IRQ_VECTOR     = 0x0108,
-    NVME_INVALID_LOG_ID         = 0x0109,
-    NVME_INVALID_FORMAT         = 0x010a,
-    NVME_FW_REQ_RESET           = 0x010b,
-    NVME_INVALID_QUEUE_DEL      = 0x010c,
-    NVME_FID_NOT_SAVEABLE       = 0x010d,
-    NVME_FID_NOT_NSID_SPEC      = 0x010f,
-    NVME_FW_REQ_SUSYSTEM_RESET  = 0x0110,
-    NVME_CONFLICTING_ATTRS      = 0x0180,
-    NVME_INVALID_PROT_INFO      = 0x0181,
-    NVME_WRITE_TO_RO            = 0x0182,
-    NVME_WRITE_FAULT            = 0x0280,
-    NVME_UNRECOVERED_READ       = 0x0281,
-    NVME_E2E_GUARD_ERROR        = 0x0282,
-    NVME_E2E_APP_ERROR          = 0x0283,
-    NVME_E2E_REF_ERROR          = 0x0284,
-    NVME_CMP_FAILURE            = 0x0285,
-    NVME_ACCESS_DENIED          = 0x0286,
-    NVME_MORE                   = 0x2000,
-    NVME_DNR                    = 0x4000,
-    NVME_NO_COMPLETE            = 0xffff,
-};
-
-typedef struct NvmeFwSlotInfoLog {
-    uint8_t     afi;
-    uint8_t     reserved1[7];
-    uint8_t     frs1[8];
-    uint8_t     frs2[8];
-    uint8_t     frs3[8];
-    uint8_t     frs4[8];
-    uint8_t     frs5[8];
-    uint8_t     frs6[8];
-    uint8_t     frs7[8];
-    uint8_t     reserved2[448];
-} NvmeFwSlotInfoLog;
-
-typedef struct NvmeErrorLog {
-    uint64_t    error_count;
-    uint16_t    sqid;
-    uint16_t    cid;
-    uint16_t    status_field;
-    uint16_t    param_error_location;
-    uint64_t    lba;
-    uint32_t    nsid;
-    uint8_t     vs;
-    uint8_t     resv[35];
-} NvmeErrorLog;
-
-typedef struct NvmeSmartLog {
-    uint8_t     critical_warning;
-    uint8_t     temperature[2];
-    uint8_t     available_spare;
-    uint8_t     available_spare_threshold;
-    uint8_t     percentage_used;
-    uint8_t     reserved1[26];
-    uint64_t    data_units_read[2];
-    uint64_t    data_units_written[2];
-    uint64_t    host_read_commands[2];
-    uint64_t    host_write_commands[2];
-    uint64_t    controller_busy_time[2];
-    uint64_t    power_cycles[2];
-    uint64_t    power_on_hours[2];
-    uint64_t    unsafe_shutdowns[2];
-    uint64_t    media_errors[2];
-    uint64_t    number_of_error_log_entries[2];
-    uint8_t     reserved2[320];
-} NvmeSmartLog;
-
-enum NvmeSmartWarn {
-    NVME_SMART_SPARE                  = 1 << 0,
-    NVME_SMART_TEMPERATURE            = 1 << 1,
-    NVME_SMART_RELIABILITY            = 1 << 2,
-    NVME_SMART_MEDIA_READ_ONLY        = 1 << 3,
-    NVME_SMART_FAILED_VOLATILE_MEDIA  = 1 << 4,
-};
-
-enum LogIdentifier {
-    NVME_LOG_ERROR_INFO     = 0x01,
-    NVME_LOG_SMART_INFO     = 0x02,
-    NVME_LOG_FW_SLOT_INFO   = 0x03,
-};
-
-typedef struct NvmePSD {
-    uint16_t    mp;
-    uint16_t    reserved;
-    uint32_t    enlat;
-    uint32_t    exlat;
-    uint8_t     rrt;
-    uint8_t     rrl;
-    uint8_t     rwt;
-    uint8_t     rwl;
-    uint8_t     resv[16];
-} NvmePSD;
-
-typedef struct NvmeIdCtrl {
-    uint16_t    vid;
-    uint16_t    ssvid;
-    uint8_t     sn[20];
-    uint8_t     mn[40];
-    uint8_t     fr[8];
-    uint8_t     rab;
-    uint8_t     ieee[3];
-    uint8_t     cmic;
-    uint8_t     mdts;
-    uint8_t     rsvd255[178];
-    uint16_t    oacs;
-    uint8_t     acl;
-    uint8_t     aerl;
-    uint8_t     frmw;
-    uint8_t     lpa;
-    uint8_t     elpe;
-    uint8_t     npss;
-    uint8_t     rsvd511[248];
-    uint8_t     sqes;
-    uint8_t     cqes;
-    uint16_t    rsvd515;
-    uint32_t    nn;
-    uint16_t    oncs;
-    uint16_t    fuses;
-    uint8_t     fna;
-    uint8_t     vwc;
-    uint16_t    awun;
-    uint16_t    awupf;
-    uint8_t     rsvd703[174];
-    uint8_t     rsvd2047[1344];
-    NvmePSD     psd[32];
-    uint8_t     vs[1024];
-} NvmeIdCtrl;
-
-enum NvmeIdCtrlOacs {
-    NVME_OACS_SECURITY  = 1 << 0,
-    NVME_OACS_FORMAT    = 1 << 1,
-    NVME_OACS_FW        = 1 << 2,
-};
-
-enum NvmeIdCtrlOncs {
-    NVME_ONCS_COMPARE       = 1 << 0,
-    NVME_ONCS_WRITE_UNCORR  = 1 << 1,
-    NVME_ONCS_DSM           = 1 << 2,
-    NVME_ONCS_WRITE_ZEROS   = 1 << 3,
-    NVME_ONCS_FEATURES      = 1 << 4,
-    NVME_ONCS_RESRVATIONS   = 1 << 5,
-};
-
-#define NVME_CTRL_SQES_MIN(sqes) ((sqes) & 0xf)
-#define NVME_CTRL_SQES_MAX(sqes) (((sqes) >> 4) & 0xf)
-#define NVME_CTRL_CQES_MIN(cqes) ((cqes) & 0xf)
-#define NVME_CTRL_CQES_MAX(cqes) (((cqes) >> 4) & 0xf)
-
-typedef struct NvmeFeatureVal {
-    uint32_t    arbitration;
-    uint32_t    power_mgmt;
-    uint32_t    temp_thresh;
-    uint32_t    err_rec;
-    uint32_t    volatile_wc;
-    uint32_t    num_queues;
-    uint32_t    int_coalescing;
-    uint32_t    *int_vector_config;
-    uint32_t    write_atomicity;
-    uint32_t    async_config;
-    uint32_t    sw_prog_marker;
-} NvmeFeatureVal;
-
-#define NVME_ARB_AB(arb)    (arb & 0x7)
-#define NVME_ARB_LPW(arb)   ((arb >> 8) & 0xff)
-#define NVME_ARB_MPW(arb)   ((arb >> 16) & 0xff)
-#define NVME_ARB_HPW(arb)   ((arb >> 24) & 0xff)
-
-#define NVME_INTC_THR(intc)     (intc & 0xff)
-#define NVME_INTC_TIME(intc)    ((intc >> 8) & 0xff)
-
-enum NvmeFeatureIds {
-    NVME_ARBITRATION                = 0x1,
-    NVME_POWER_MANAGEMENT           = 0x2,
-    NVME_LBA_RANGE_TYPE             = 0x3,
-    NVME_TEMPERATURE_THRESHOLD      = 0x4,
-    NVME_ERROR_RECOVERY             = 0x5,
-    NVME_VOLATILE_WRITE_CACHE       = 0x6,
-    NVME_NUMBER_OF_QUEUES           = 0x7,
-    NVME_INTERRUPT_COALESCING       = 0x8,
-    NVME_INTERRUPT_VECTOR_CONF      = 0x9,
-    NVME_WRITE_ATOMICITY            = 0xa,
-    NVME_ASYNCHRONOUS_EVENT_CONF    = 0xb,
-    NVME_SOFTWARE_PROGRESS_MARKER   = 0x80
-};
-
-typedef struct NvmeRangeType {
-    uint8_t     type;
-    uint8_t     attributes;
-    uint8_t     rsvd2[14];
-    uint64_t    slba;
-    uint64_t    nlb;
-    uint8_t     guid[16];
-    uint8_t     rsvd48[16];
-} NvmeRangeType;
-
-typedef struct NvmeLBAF {
-    uint16_t    ms;
-    uint8_t     ds;
-    uint8_t     rp;
-} NvmeLBAF;
-
-typedef struct NvmeIdNs {
-    uint64_t    nsze;
-    uint64_t    ncap;
-    uint64_t    nuse;
-    uint8_t     nsfeat;
-    uint8_t     nlbaf;
-    uint8_t     flbas;
-    uint8_t     mc;
-    uint8_t     dpc;
-    uint8_t     dps;
-    uint8_t     res30[98];
-    NvmeLBAF    lbaf[16];
-    uint8_t     res192[192];
-    uint8_t     vs[3712];
-} NvmeIdNs;
-
-#define NVME_ID_NS_NSFEAT_THIN(nsfeat)      ((nsfeat & 0x1))
-#define NVME_ID_NS_FLBAS_EXTENDED(flbas)    ((flbas >> 4) & 0x1)
-#define NVME_ID_NS_FLBAS_INDEX(flbas)       ((flbas & 0xf))
-#define NVME_ID_NS_MC_SEPARATE(mc)          ((mc >> 1) & 0x1)
-#define NVME_ID_NS_MC_EXTENDED(mc)          ((mc & 0x1))
-#define NVME_ID_NS_DPC_LAST_EIGHT(dpc)      ((dpc >> 4) & 0x1)
-#define NVME_ID_NS_DPC_FIRST_EIGHT(dpc)     ((dpc >> 3) & 0x1)
-#define NVME_ID_NS_DPC_TYPE_3(dpc)          ((dpc >> 2) & 0x1)
-#define NVME_ID_NS_DPC_TYPE_2(dpc)          ((dpc >> 1) & 0x1)
-#define NVME_ID_NS_DPC_TYPE_1(dpc)          ((dpc & 0x1))
-#define NVME_ID_NS_DPC_TYPE_MASK            0x7
-
-enum NvmeIdNsDps {
-    DPS_TYPE_NONE   = 0,
-    DPS_TYPE_1      = 1,
-    DPS_TYPE_2      = 2,
-    DPS_TYPE_3      = 3,
-    DPS_TYPE_MASK   = 0x7,
-    DPS_FIRST_EIGHT = 8,
-};
-
-static inline void _nvme_check_size(void)
-{
-    QEMU_BUILD_BUG_ON(sizeof(NvmeAerResult) != 4);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeCqe) != 16);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeDsmRange) != 16);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeCmd) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeDeleteQ) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeCreateCq) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeCreateSq) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeIdentify) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeRwCmd) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeDsmCmd) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeRangeType) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeErrorLog) != 64);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeFwSlotInfoLog) != 512);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeSmartLog) != 512);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeIdCtrl) != 4096);
-    QEMU_BUILD_BUG_ON(sizeof(NvmeIdNs) != 4096);
-}
+#include "block/nvme.h"
 
 typedef struct NvmeAsyncEvent {
     QSIMPLEQ_ENTRY(NvmeAsyncEvent) entry;
diff --git a/include/block/block.h b/include/block/block.h
index 9b12774..2025d7e 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -631,5 +631,14 @@ void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 
 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
                                      uint32_t granularity, Error **errp);
-
+/**
+ *
+ * bdrv_register_buf/bdrv_unregister_buf:
+ *
+ * Register/unregister a buffer for I/O. For example, VFIO drivers are
+ * interested to know the memory areas that would later be used for I/O, so
+ * that they can prepare IOMMU mapping etc., to get better performance.
+ */
+void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
+void bdrv_unregister_buf(BlockDriverState *bs, void *host);
 #endif
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 29cafa4..99b9190 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -446,6 +446,15 @@ struct BlockDriver {
                                                 const char *name,
                                                 Error **errp);
 
+    /**
+     * Register/unregister a buffer for I/O. For example, when the driver is
+     * interested to know the memory areas that will later be used in iovs, so
+     * that it can do IOMMU mapping with VFIO etc., in order to get better
+     * performance. In the case of VFIO drivers, this callback is used to do
+     * DMA mapping for hot buffers.
+     */
+    void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size);
+    void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host);
     QLIST_ENTRY(BlockDriver) list;
 };
 
diff --git a/include/block/nvme.h b/include/block/nvme.h
new file mode 100644
index 0000000..849a6f3
--- /dev/null
+++ b/include/block/nvme.h
@@ -0,0 +1,700 @@
+#ifndef BLOCK_NVME_H
+#define BLOCK_NVME_H
+
+typedef struct NvmeBar {
+    uint64_t    cap;
+    uint32_t    vs;
+    uint32_t    intms;
+    uint32_t    intmc;
+    uint32_t    cc;
+    uint32_t    rsvd1;
+    uint32_t    csts;
+    uint32_t    nssrc;
+    uint32_t    aqa;
+    uint64_t    asq;
+    uint64_t    acq;
+    uint32_t    cmbloc;
+    uint32_t    cmbsz;
+} NvmeBar;
+
+enum NvmeCapShift {
+    CAP_MQES_SHIFT     = 0,
+    CAP_CQR_SHIFT      = 16,
+    CAP_AMS_SHIFT      = 17,
+    CAP_TO_SHIFT       = 24,
+    CAP_DSTRD_SHIFT    = 32,
+    CAP_NSSRS_SHIFT    = 33,
+    CAP_CSS_SHIFT      = 37,
+    CAP_MPSMIN_SHIFT   = 48,
+    CAP_MPSMAX_SHIFT   = 52,
+};
+
+enum NvmeCapMask {
+    CAP_MQES_MASK      = 0xffff,
+    CAP_CQR_MASK       = 0x1,
+    CAP_AMS_MASK       = 0x3,
+    CAP_TO_MASK        = 0xff,
+    CAP_DSTRD_MASK     = 0xf,
+    CAP_NSSRS_MASK     = 0x1,
+    CAP_CSS_MASK       = 0xff,
+    CAP_MPSMIN_MASK    = 0xf,
+    CAP_MPSMAX_MASK    = 0xf,
+};
+
+#define NVME_CAP_MQES(cap)  (((cap) >> CAP_MQES_SHIFT)   & CAP_MQES_MASK)
+#define NVME_CAP_CQR(cap)   (((cap) >> CAP_CQR_SHIFT)    & CAP_CQR_MASK)
+#define NVME_CAP_AMS(cap)   (((cap) >> CAP_AMS_SHIFT)    & CAP_AMS_MASK)
+#define NVME_CAP_TO(cap)    (((cap) >> CAP_TO_SHIFT)     & CAP_TO_MASK)
+#define NVME_CAP_DSTRD(cap) (((cap) >> CAP_DSTRD_SHIFT)  & CAP_DSTRD_MASK)
+#define NVME_CAP_NSSRS(cap) (((cap) >> CAP_NSSRS_SHIFT)  & CAP_NSSRS_MASK)
+#define NVME_CAP_CSS(cap)   (((cap) >> CAP_CSS_SHIFT)    & CAP_CSS_MASK)
+#define NVME_CAP_MPSMIN(cap)(((cap) >> CAP_MPSMIN_SHIFT) & CAP_MPSMIN_MASK)
+#define NVME_CAP_MPSMAX(cap)(((cap) >> CAP_MPSMAX_SHIFT) & CAP_MPSMAX_MASK)
+
+#define NVME_CAP_SET_MQES(cap, val)   (cap |= (uint64_t)(val & CAP_MQES_MASK)  \
+                                                           << CAP_MQES_SHIFT)
+#define NVME_CAP_SET_CQR(cap, val)    (cap |= (uint64_t)(val & CAP_CQR_MASK)   \
+                                                           << CAP_CQR_SHIFT)
+#define NVME_CAP_SET_AMS(cap, val)    (cap |= (uint64_t)(val & CAP_AMS_MASK)   \
+                                                           << CAP_AMS_SHIFT)
+#define NVME_CAP_SET_TO(cap, val)     (cap |= (uint64_t)(val & CAP_TO_MASK)    \
+                                                           << CAP_TO_SHIFT)
+#define NVME_CAP_SET_DSTRD(cap, val)  (cap |= (uint64_t)(val & CAP_DSTRD_MASK) \
+                                                           << CAP_DSTRD_SHIFT)
+#define NVME_CAP_SET_NSSRS(cap, val)  (cap |= (uint64_t)(val & CAP_NSSRS_MASK) \
+                                                           << CAP_NSSRS_SHIFT)
+#define NVME_CAP_SET_CSS(cap, val)    (cap |= (uint64_t)(val & CAP_CSS_MASK)   \
+                                                           << CAP_CSS_SHIFT)
+#define NVME_CAP_SET_MPSMIN(cap, val) (cap |= (uint64_t)(val & CAP_MPSMIN_MASK)\
+                                                           << CAP_MPSMIN_SHIFT)
+#define NVME_CAP_SET_MPSMAX(cap, val) (cap |= (uint64_t)(val & CAP_MPSMAX_MASK)\
+                                                            << CAP_MPSMAX_SHIFT)
+
+enum NvmeCcShift {
+    CC_EN_SHIFT     = 0,
+    CC_CSS_SHIFT    = 4,
+    CC_MPS_SHIFT    = 7,
+    CC_AMS_SHIFT    = 11,
+    CC_SHN_SHIFT    = 14,
+    CC_IOSQES_SHIFT = 16,
+    CC_IOCQES_SHIFT = 20,
+};
+
+enum NvmeCcMask {
+    CC_EN_MASK      = 0x1,
+    CC_CSS_MASK     = 0x7,
+    CC_MPS_MASK     = 0xf,
+    CC_AMS_MASK     = 0x7,
+    CC_SHN_MASK     = 0x3,
+    CC_IOSQES_MASK  = 0xf,
+    CC_IOCQES_MASK  = 0xf,
+};
+
+#define NVME_CC_EN(cc)     ((cc >> CC_EN_SHIFT)     & CC_EN_MASK)
+#define NVME_CC_CSS(cc)    ((cc >> CC_CSS_SHIFT)    & CC_CSS_MASK)
+#define NVME_CC_MPS(cc)    ((cc >> CC_MPS_SHIFT)    & CC_MPS_MASK)
+#define NVME_CC_AMS(cc)    ((cc >> CC_AMS_SHIFT)    & CC_AMS_MASK)
+#define NVME_CC_SHN(cc)    ((cc >> CC_SHN_SHIFT)    & CC_SHN_MASK)
+#define NVME_CC_IOSQES(cc) ((cc >> CC_IOSQES_SHIFT) & CC_IOSQES_MASK)
+#define NVME_CC_IOCQES(cc) ((cc >> CC_IOCQES_SHIFT) & CC_IOCQES_MASK)
+
+enum NvmeCstsShift {
+    CSTS_RDY_SHIFT      = 0,
+    CSTS_CFS_SHIFT      = 1,
+    CSTS_SHST_SHIFT     = 2,
+    CSTS_NSSRO_SHIFT    = 4,
+};
+
+enum NvmeCstsMask {
+    CSTS_RDY_MASK   = 0x1,
+    CSTS_CFS_MASK   = 0x1,
+    CSTS_SHST_MASK  = 0x3,
+    CSTS_NSSRO_MASK = 0x1,
+};
+
+enum NvmeCsts {
+    NVME_CSTS_READY         = 1 << CSTS_RDY_SHIFT,
+    NVME_CSTS_FAILED        = 1 << CSTS_CFS_SHIFT,
+    NVME_CSTS_SHST_NORMAL   = 0 << CSTS_SHST_SHIFT,
+    NVME_CSTS_SHST_PROGRESS = 1 << CSTS_SHST_SHIFT,
+    NVME_CSTS_SHST_COMPLETE = 2 << CSTS_SHST_SHIFT,
+    NVME_CSTS_NSSRO         = 1 << CSTS_NSSRO_SHIFT,
+};
+
+#define NVME_CSTS_RDY(csts)     ((csts >> CSTS_RDY_SHIFT)   & CSTS_RDY_MASK)
+#define NVME_CSTS_CFS(csts)     ((csts >> CSTS_CFS_SHIFT)   & CSTS_CFS_MASK)
+#define NVME_CSTS_SHST(csts)    ((csts >> CSTS_SHST_SHIFT)  & CSTS_SHST_MASK)
+#define NVME_CSTS_NSSRO(csts)   ((csts >> CSTS_NSSRO_SHIFT) & CSTS_NSSRO_MASK)
+
+enum NvmeAqaShift {
+    AQA_ASQS_SHIFT  = 0,
+    AQA_ACQS_SHIFT  = 16,
+};
+
+enum NvmeAqaMask {
+    AQA_ASQS_MASK   = 0xfff,
+    AQA_ACQS_MASK   = 0xfff,
+};
+
+#define NVME_AQA_ASQS(aqa) ((aqa >> AQA_ASQS_SHIFT) & AQA_ASQS_MASK)
+#define NVME_AQA_ACQS(aqa) ((aqa >> AQA_ACQS_SHIFT) & AQA_ACQS_MASK)
+
+enum NvmeCmblocShift {
+    CMBLOC_BIR_SHIFT  = 0,
+    CMBLOC_OFST_SHIFT = 12,
+};
+
+enum NvmeCmblocMask {
+    CMBLOC_BIR_MASK  = 0x7,
+    CMBLOC_OFST_MASK = 0xfffff,
+};
+
+#define NVME_CMBLOC_BIR(cmbloc) ((cmbloc >> CMBLOC_BIR_SHIFT)  & \
+                                 CMBLOC_BIR_MASK)
+#define NVME_CMBLOC_OFST(cmbloc)((cmbloc >> CMBLOC_OFST_SHIFT) & \
+                                 CMBLOC_OFST_MASK)
+
+#define NVME_CMBLOC_SET_BIR(cmbloc, val)  \
+    (cmbloc |= (uint64_t)(val & CMBLOC_BIR_MASK) << CMBLOC_BIR_SHIFT)
+#define NVME_CMBLOC_SET_OFST(cmbloc, val) \
+    (cmbloc |= (uint64_t)(val & CMBLOC_OFST_MASK) << CMBLOC_OFST_SHIFT)
+
+enum NvmeCmbszShift {
+    CMBSZ_SQS_SHIFT   = 0,
+    CMBSZ_CQS_SHIFT   = 1,
+    CMBSZ_LISTS_SHIFT = 2,
+    CMBSZ_RDS_SHIFT   = 3,
+    CMBSZ_WDS_SHIFT   = 4,
+    CMBSZ_SZU_SHIFT   = 8,
+    CMBSZ_SZ_SHIFT    = 12,
+};
+
+enum NvmeCmbszMask {
+    CMBSZ_SQS_MASK   = 0x1,
+    CMBSZ_CQS_MASK   = 0x1,
+    CMBSZ_LISTS_MASK = 0x1,
+    CMBSZ_RDS_MASK   = 0x1,
+    CMBSZ_WDS_MASK   = 0x1,
+    CMBSZ_SZU_MASK   = 0xf,
+    CMBSZ_SZ_MASK    = 0xfffff,
+};
+
+#define NVME_CMBSZ_SQS(cmbsz)  ((cmbsz >> CMBSZ_SQS_SHIFT)   & CMBSZ_SQS_MASK)
+#define NVME_CMBSZ_CQS(cmbsz)  ((cmbsz >> CMBSZ_CQS_SHIFT)   & CMBSZ_CQS_MASK)
+#define NVME_CMBSZ_LISTS(cmbsz)((cmbsz >> CMBSZ_LISTS_SHIFT) & CMBSZ_LISTS_MASK)
+#define NVME_CMBSZ_RDS(cmbsz)  ((cmbsz >> CMBSZ_RDS_SHIFT)   & CMBSZ_RDS_MASK)
+#define NVME_CMBSZ_WDS(cmbsz)  ((cmbsz >> CMBSZ_WDS_SHIFT)   & CMBSZ_WDS_MASK)
+#define NVME_CMBSZ_SZU(cmbsz)  ((cmbsz >> CMBSZ_SZU_SHIFT)   & CMBSZ_SZU_MASK)
+#define NVME_CMBSZ_SZ(cmbsz)   ((cmbsz >> CMBSZ_SZ_SHIFT)    & CMBSZ_SZ_MASK)
+
+#define NVME_CMBSZ_SET_SQS(cmbsz, val)   \
+    (cmbsz |= (uint64_t)(val &  CMBSZ_SQS_MASK)  << CMBSZ_SQS_SHIFT)
+#define NVME_CMBSZ_SET_CQS(cmbsz, val)   \
+    (cmbsz |= (uint64_t)(val & CMBSZ_CQS_MASK) << CMBSZ_CQS_SHIFT)
+#define NVME_CMBSZ_SET_LISTS(cmbsz, val) \
+    (cmbsz |= (uint64_t)(val & CMBSZ_LISTS_MASK) << CMBSZ_LISTS_SHIFT)
+#define NVME_CMBSZ_SET_RDS(cmbsz, val)   \
+    (cmbsz |= (uint64_t)(val & CMBSZ_RDS_MASK) << CMBSZ_RDS_SHIFT)
+#define NVME_CMBSZ_SET_WDS(cmbsz, val)   \
+    (cmbsz |= (uint64_t)(val & CMBSZ_WDS_MASK) << CMBSZ_WDS_SHIFT)
+#define NVME_CMBSZ_SET_SZU(cmbsz, val)   \
+    (cmbsz |= (uint64_t)(val & CMBSZ_SZU_MASK) << CMBSZ_SZU_SHIFT)
+#define NVME_CMBSZ_SET_SZ(cmbsz, val)    \
+    (cmbsz |= (uint64_t)(val & CMBSZ_SZ_MASK) << CMBSZ_SZ_SHIFT)
+
+#define NVME_CMBSZ_GETSIZE(cmbsz) \
+    (NVME_CMBSZ_SZ(cmbsz) * (1 << (12 + 4 * NVME_CMBSZ_SZU(cmbsz))))
+
+typedef struct NvmeCmd {
+    uint8_t     opcode;
+    uint8_t     fuse;
+    uint16_t    cid;
+    uint32_t    nsid;
+    uint64_t    res1;
+    uint64_t    mptr;
+    uint64_t    prp1;
+    uint64_t    prp2;
+    uint32_t    cdw10;
+    uint32_t    cdw11;
+    uint32_t    cdw12;
+    uint32_t    cdw13;
+    uint32_t    cdw14;
+    uint32_t    cdw15;
+} NvmeCmd;
+
+enum NvmeAdminCommands {
+    NVME_ADM_CMD_DELETE_SQ      = 0x00,
+    NVME_ADM_CMD_CREATE_SQ      = 0x01,
+    NVME_ADM_CMD_GET_LOG_PAGE   = 0x02,
+    NVME_ADM_CMD_DELETE_CQ      = 0x04,
+    NVME_ADM_CMD_CREATE_CQ      = 0x05,
+    NVME_ADM_CMD_IDENTIFY       = 0x06,
+    NVME_ADM_CMD_ABORT          = 0x08,
+    NVME_ADM_CMD_SET_FEATURES   = 0x09,
+    NVME_ADM_CMD_GET_FEATURES   = 0x0a,
+    NVME_ADM_CMD_ASYNC_EV_REQ   = 0x0c,
+    NVME_ADM_CMD_ACTIVATE_FW    = 0x10,
+    NVME_ADM_CMD_DOWNLOAD_FW    = 0x11,
+    NVME_ADM_CMD_FORMAT_NVM     = 0x80,
+    NVME_ADM_CMD_SECURITY_SEND  = 0x81,
+    NVME_ADM_CMD_SECURITY_RECV  = 0x82,
+};
+
+enum NvmeIoCommands {
+    NVME_CMD_FLUSH              = 0x00,
+    NVME_CMD_WRITE              = 0x01,
+    NVME_CMD_READ               = 0x02,
+    NVME_CMD_WRITE_UNCOR        = 0x04,
+    NVME_CMD_COMPARE            = 0x05,
+    NVME_CMD_WRITE_ZEROS        = 0x08,
+    NVME_CMD_DSM                = 0x09,
+};
+
+typedef struct NvmeDeleteQ {
+    uint8_t     opcode;
+    uint8_t     flags;
+    uint16_t    cid;
+    uint32_t    rsvd1[9];
+    uint16_t    qid;
+    uint16_t    rsvd10;
+    uint32_t    rsvd11[5];
+} NvmeDeleteQ;
+
+typedef struct NvmeCreateCq {
+    uint8_t     opcode;
+    uint8_t     flags;
+    uint16_t    cid;
+    uint32_t    rsvd1[5];
+    uint64_t    prp1;
+    uint64_t    rsvd8;
+    uint16_t    cqid;
+    uint16_t    qsize;
+    uint16_t    cq_flags;
+    uint16_t    irq_vector;
+    uint32_t    rsvd12[4];
+} NvmeCreateCq;
+
+#define NVME_CQ_FLAGS_PC(cq_flags)  (cq_flags & 0x1)
+#define NVME_CQ_FLAGS_IEN(cq_flags) ((cq_flags >> 1) & 0x1)
+
+typedef struct NvmeCreateSq {
+    uint8_t     opcode;
+    uint8_t     flags;
+    uint16_t    cid;
+    uint32_t    rsvd1[5];
+    uint64_t    prp1;
+    uint64_t    rsvd8;
+    uint16_t    sqid;
+    uint16_t    qsize;
+    uint16_t    sq_flags;
+    uint16_t    cqid;
+    uint32_t    rsvd12[4];
+} NvmeCreateSq;
+
+#define NVME_SQ_FLAGS_PC(sq_flags)      (sq_flags & 0x1)
+#define NVME_SQ_FLAGS_QPRIO(sq_flags)   ((sq_flags >> 1) & 0x3)
+
+enum NvmeQueueFlags {
+    NVME_Q_PC           = 1,
+    NVME_Q_PRIO_URGENT  = 0,
+    NVME_Q_PRIO_HIGH    = 1,
+    NVME_Q_PRIO_NORMAL  = 2,
+    NVME_Q_PRIO_LOW     = 3,
+};
+
+typedef struct NvmeIdentify {
+    uint8_t     opcode;
+    uint8_t     flags;
+    uint16_t    cid;
+    uint32_t    nsid;
+    uint64_t    rsvd2[2];
+    uint64_t    prp1;
+    uint64_t    prp2;
+    uint32_t    cns;
+    uint32_t    rsvd11[5];
+} NvmeIdentify;
+
+typedef struct NvmeRwCmd {
+    uint8_t     opcode;
+    uint8_t     flags;
+    uint16_t    cid;
+    uint32_t    nsid;
+    uint64_t    rsvd2;
+    uint64_t    mptr;
+    uint64_t    prp1;
+    uint64_t    prp2;
+    uint64_t    slba;
+    uint16_t    nlb;
+    uint16_t    control;
+    uint32_t    dsmgmt;
+    uint32_t    reftag;
+    uint16_t    apptag;
+    uint16_t    appmask;
+} NvmeRwCmd;
+
+enum {
+    NVME_RW_LR                  = 1 << 15,
+    NVME_RW_FUA                 = 1 << 14,
+    NVME_RW_DSM_FREQ_UNSPEC     = 0,
+    NVME_RW_DSM_FREQ_TYPICAL    = 1,
+    NVME_RW_DSM_FREQ_RARE       = 2,
+    NVME_RW_DSM_FREQ_READS      = 3,
+    NVME_RW_DSM_FREQ_WRITES     = 4,
+    NVME_RW_DSM_FREQ_RW         = 5,
+    NVME_RW_DSM_FREQ_ONCE       = 6,
+    NVME_RW_DSM_FREQ_PREFETCH   = 7,
+    NVME_RW_DSM_FREQ_TEMP       = 8,
+    NVME_RW_DSM_LATENCY_NONE    = 0 << 4,
+    NVME_RW_DSM_LATENCY_IDLE    = 1 << 4,
+    NVME_RW_DSM_LATENCY_NORM    = 2 << 4,
+    NVME_RW_DSM_LATENCY_LOW     = 3 << 4,
+    NVME_RW_DSM_SEQ_REQ         = 1 << 6,
+    NVME_RW_DSM_COMPRESSED      = 1 << 7,
+    NVME_RW_PRINFO_PRACT        = 1 << 13,
+    NVME_RW_PRINFO_PRCHK_GUARD  = 1 << 12,
+    NVME_RW_PRINFO_PRCHK_APP    = 1 << 11,
+    NVME_RW_PRINFO_PRCHK_REF    = 1 << 10,
+};
+
+typedef struct NvmeDsmCmd {
+    uint8_t     opcode;
+    uint8_t     flags;
+    uint16_t    cid;
+    uint32_t    nsid;
+    uint64_t    rsvd2[2];
+    uint64_t    prp1;
+    uint64_t    prp2;
+    uint32_t    nr;
+    uint32_t    attributes;
+    uint32_t    rsvd12[4];
+} NvmeDsmCmd;
+
+enum {
+    NVME_DSMGMT_IDR = 1 << 0,
+    NVME_DSMGMT_IDW = 1 << 1,
+    NVME_DSMGMT_AD  = 1 << 2,
+};
+
+typedef struct NvmeDsmRange {
+    uint32_t    cattr;
+    uint32_t    nlb;
+    uint64_t    slba;
+} NvmeDsmRange;
+
+enum NvmeAsyncEventRequest {
+    NVME_AER_TYPE_ERROR                     = 0,
+    NVME_AER_TYPE_SMART                     = 1,
+    NVME_AER_TYPE_IO_SPECIFIC               = 6,
+    NVME_AER_TYPE_VENDOR_SPECIFIC           = 7,
+    NVME_AER_INFO_ERR_INVALID_SQ            = 0,
+    NVME_AER_INFO_ERR_INVALID_DB            = 1,
+    NVME_AER_INFO_ERR_DIAG_FAIL             = 2,
+    NVME_AER_INFO_ERR_PERS_INTERNAL_ERR     = 3,
+    NVME_AER_INFO_ERR_TRANS_INTERNAL_ERR    = 4,
+    NVME_AER_INFO_ERR_FW_IMG_LOAD_ERR       = 5,
+    NVME_AER_INFO_SMART_RELIABILITY         = 0,
+    NVME_AER_INFO_SMART_TEMP_THRESH         = 1,
+    NVME_AER_INFO_SMART_SPARE_THRESH        = 2,
+};
+
+typedef struct NvmeAerResult {
+    uint8_t event_type;
+    uint8_t event_info;
+    uint8_t log_page;
+    uint8_t resv;
+} NvmeAerResult;
+
+typedef struct NvmeCqe {
+    uint32_t    result;
+    uint32_t    rsvd;
+    uint16_t    sq_head;
+    uint16_t    sq_id;
+    uint16_t    cid;
+    uint16_t    status;
+} NvmeCqe;
+
+enum NvmeStatusCodes {
+    NVME_SUCCESS                = 0x0000,
+    NVME_INVALID_OPCODE         = 0x0001,
+    NVME_INVALID_FIELD          = 0x0002,
+    NVME_CID_CONFLICT           = 0x0003,
+    NVME_DATA_TRAS_ERROR        = 0x0004,
+    NVME_POWER_LOSS_ABORT       = 0x0005,
+    NVME_INTERNAL_DEV_ERROR     = 0x0006,
+    NVME_CMD_ABORT_REQ          = 0x0007,
+    NVME_CMD_ABORT_SQ_DEL       = 0x0008,
+    NVME_CMD_ABORT_FAILED_FUSE  = 0x0009,
+    NVME_CMD_ABORT_MISSING_FUSE = 0x000a,
+    NVME_INVALID_NSID           = 0x000b,
+    NVME_CMD_SEQ_ERROR          = 0x000c,
+    NVME_LBA_RANGE              = 0x0080,
+    NVME_CAP_EXCEEDED           = 0x0081,
+    NVME_NS_NOT_READY           = 0x0082,
+    NVME_NS_RESV_CONFLICT       = 0x0083,
+    NVME_INVALID_CQID           = 0x0100,
+    NVME_INVALID_QID            = 0x0101,
+    NVME_MAX_QSIZE_EXCEEDED     = 0x0102,
+    NVME_ACL_EXCEEDED           = 0x0103,
+    NVME_RESERVED               = 0x0104,
+    NVME_AER_LIMIT_EXCEEDED     = 0x0105,
+    NVME_INVALID_FW_SLOT        = 0x0106,
+    NVME_INVALID_FW_IMAGE       = 0x0107,
+    NVME_INVALID_IRQ_VECTOR     = 0x0108,
+    NVME_INVALID_LOG_ID         = 0x0109,
+    NVME_INVALID_FORMAT         = 0x010a,
+    NVME_FW_REQ_RESET           = 0x010b,
+    NVME_INVALID_QUEUE_DEL      = 0x010c,
+    NVME_FID_NOT_SAVEABLE       = 0x010d,
+    NVME_FID_NOT_NSID_SPEC      = 0x010f,
+    NVME_FW_REQ_SUSYSTEM_RESET  = 0x0110,
+    NVME_CONFLICTING_ATTRS      = 0x0180,
+    NVME_INVALID_PROT_INFO      = 0x0181,
+    NVME_WRITE_TO_RO            = 0x0182,
+    NVME_WRITE_FAULT            = 0x0280,
+    NVME_UNRECOVERED_READ       = 0x0281,
+    NVME_E2E_GUARD_ERROR        = 0x0282,
+    NVME_E2E_APP_ERROR          = 0x0283,
+    NVME_E2E_REF_ERROR          = 0x0284,
+    NVME_CMP_FAILURE            = 0x0285,
+    NVME_ACCESS_DENIED          = 0x0286,
+    NVME_MORE                   = 0x2000,
+    NVME_DNR                    = 0x4000,
+    NVME_NO_COMPLETE            = 0xffff,
+};
+
+typedef struct NvmeFwSlotInfoLog {
+    uint8_t     afi;
+    uint8_t     reserved1[7];
+    uint8_t     frs1[8];
+    uint8_t     frs2[8];
+    uint8_t     frs3[8];
+    uint8_t     frs4[8];
+    uint8_t     frs5[8];
+    uint8_t     frs6[8];
+    uint8_t     frs7[8];
+    uint8_t     reserved2[448];
+} NvmeFwSlotInfoLog;
+
+typedef struct NvmeErrorLog {
+    uint64_t    error_count;
+    uint16_t    sqid;
+    uint16_t    cid;
+    uint16_t    status_field;
+    uint16_t    param_error_location;
+    uint64_t    lba;
+    uint32_t    nsid;
+    uint8_t     vs;
+    uint8_t     resv[35];
+} NvmeErrorLog;
+
+typedef struct NvmeSmartLog {
+    uint8_t     critical_warning;
+    uint8_t     temperature[2];
+    uint8_t     available_spare;
+    uint8_t     available_spare_threshold;
+    uint8_t     percentage_used;
+    uint8_t     reserved1[26];
+    uint64_t    data_units_read[2];
+    uint64_t    data_units_written[2];
+    uint64_t    host_read_commands[2];
+    uint64_t    host_write_commands[2];
+    uint64_t    controller_busy_time[2];
+    uint64_t    power_cycles[2];
+    uint64_t    power_on_hours[2];
+    uint64_t    unsafe_shutdowns[2];
+    uint64_t    media_errors[2];
+    uint64_t    number_of_error_log_entries[2];
+    uint8_t     reserved2[320];
+} NvmeSmartLog;
+
+enum NvmeSmartWarn {
+    NVME_SMART_SPARE                  = 1 << 0,
+    NVME_SMART_TEMPERATURE            = 1 << 1,
+    NVME_SMART_RELIABILITY            = 1 << 2,
+    NVME_SMART_MEDIA_READ_ONLY        = 1 << 3,
+    NVME_SMART_FAILED_VOLATILE_MEDIA  = 1 << 4,
+};
+
+enum LogIdentifier {
+    NVME_LOG_ERROR_INFO     = 0x01,
+    NVME_LOG_SMART_INFO     = 0x02,
+    NVME_LOG_FW_SLOT_INFO   = 0x03,
+};
+
+typedef struct NvmePSD {
+    uint16_t    mp;
+    uint16_t    reserved;
+    uint32_t    enlat;
+    uint32_t    exlat;
+    uint8_t     rrt;
+    uint8_t     rrl;
+    uint8_t     rwt;
+    uint8_t     rwl;
+    uint8_t     resv[16];
+} NvmePSD;
+
+typedef struct NvmeIdCtrl {
+    uint16_t    vid;
+    uint16_t    ssvid;
+    uint8_t     sn[20];
+    uint8_t     mn[40];
+    uint8_t     fr[8];
+    uint8_t     rab;
+    uint8_t     ieee[3];
+    uint8_t     cmic;
+    uint8_t     mdts;
+    uint8_t     rsvd255[178];
+    uint16_t    oacs;
+    uint8_t     acl;
+    uint8_t     aerl;
+    uint8_t     frmw;
+    uint8_t     lpa;
+    uint8_t     elpe;
+    uint8_t     npss;
+    uint8_t     rsvd511[248];
+    uint8_t     sqes;
+    uint8_t     cqes;
+    uint16_t    rsvd515;
+    uint32_t    nn;
+    uint16_t    oncs;
+    uint16_t    fuses;
+    uint8_t     fna;
+    uint8_t     vwc;
+    uint16_t    awun;
+    uint16_t    awupf;
+    uint8_t     rsvd703[174];
+    uint8_t     rsvd2047[1344];
+    NvmePSD     psd[32];
+    uint8_t     vs[1024];
+} NvmeIdCtrl;
+
+enum NvmeIdCtrlOacs {
+    NVME_OACS_SECURITY  = 1 << 0,
+    NVME_OACS_FORMAT    = 1 << 1,
+    NVME_OACS_FW        = 1 << 2,
+};
+
+enum NvmeIdCtrlOncs {
+    NVME_ONCS_COMPARE       = 1 << 0,
+    NVME_ONCS_WRITE_UNCORR  = 1 << 1,
+    NVME_ONCS_DSM           = 1 << 2,
+    NVME_ONCS_WRITE_ZEROS   = 1 << 3,
+    NVME_ONCS_FEATURES      = 1 << 4,
+    NVME_ONCS_RESRVATIONS   = 1 << 5,
+};
+
+#define NVME_CTRL_SQES_MIN(sqes) ((sqes) & 0xf)
+#define NVME_CTRL_SQES_MAX(sqes) (((sqes) >> 4) & 0xf)
+#define NVME_CTRL_CQES_MIN(cqes) ((cqes) & 0xf)
+#define NVME_CTRL_CQES_MAX(cqes) (((cqes) >> 4) & 0xf)
+
+typedef struct NvmeFeatureVal {
+    uint32_t    arbitration;
+    uint32_t    power_mgmt;
+    uint32_t    temp_thresh;
+    uint32_t    err_rec;
+    uint32_t    volatile_wc;
+    uint32_t    num_queues;
+    uint32_t    int_coalescing;
+    uint32_t    *int_vector_config;
+    uint32_t    write_atomicity;
+    uint32_t    async_config;
+    uint32_t    sw_prog_marker;
+} NvmeFeatureVal;
+
+#define NVME_ARB_AB(arb)    (arb & 0x7)
+#define NVME_ARB_LPW(arb)   ((arb >> 8) & 0xff)
+#define NVME_ARB_MPW(arb)   ((arb >> 16) & 0xff)
+#define NVME_ARB_HPW(arb)   ((arb >> 24) & 0xff)
+
+#define NVME_INTC_THR(intc)     (intc & 0xff)
+#define NVME_INTC_TIME(intc)    ((intc >> 8) & 0xff)
+
+enum NvmeFeatureIds {
+    NVME_ARBITRATION                = 0x1,
+    NVME_POWER_MANAGEMENT           = 0x2,
+    NVME_LBA_RANGE_TYPE             = 0x3,
+    NVME_TEMPERATURE_THRESHOLD      = 0x4,
+    NVME_ERROR_RECOVERY             = 0x5,
+    NVME_VOLATILE_WRITE_CACHE       = 0x6,
+    NVME_NUMBER_OF_QUEUES           = 0x7,
+    NVME_INTERRUPT_COALESCING       = 0x8,
+    NVME_INTERRUPT_VECTOR_CONF      = 0x9,
+    NVME_WRITE_ATOMICITY            = 0xa,
+    NVME_ASYNCHRONOUS_EVENT_CONF    = 0xb,
+    NVME_SOFTWARE_PROGRESS_MARKER   = 0x80
+};
+
+typedef struct NvmeRangeType {
+    uint8_t     type;
+    uint8_t     attributes;
+    uint8_t     rsvd2[14];
+    uint64_t    slba;
+    uint64_t    nlb;
+    uint8_t     guid[16];
+    uint8_t     rsvd48[16];
+} NvmeRangeType;
+
+typedef struct NvmeLBAF {
+    uint16_t    ms;
+    uint8_t     ds;
+    uint8_t     rp;
+} NvmeLBAF;
+
+typedef struct NvmeIdNs {
+    uint64_t    nsze;
+    uint64_t    ncap;
+    uint64_t    nuse;
+    uint8_t     nsfeat;
+    uint8_t     nlbaf;
+    uint8_t     flbas;
+    uint8_t     mc;
+    uint8_t     dpc;
+    uint8_t     dps;
+    uint8_t     res30[98];
+    NvmeLBAF    lbaf[16];
+    uint8_t     res192[192];
+    uint8_t     vs[3712];
+} NvmeIdNs;
+
+#define NVME_ID_NS_NSFEAT_THIN(nsfeat)      ((nsfeat & 0x1))
+#define NVME_ID_NS_FLBAS_EXTENDED(flbas)    ((flbas >> 4) & 0x1)
+#define NVME_ID_NS_FLBAS_INDEX(flbas)       ((flbas & 0xf))
+#define NVME_ID_NS_MC_SEPARATE(mc)          ((mc >> 1) & 0x1)
+#define NVME_ID_NS_MC_EXTENDED(mc)          ((mc & 0x1))
+#define NVME_ID_NS_DPC_LAST_EIGHT(dpc)      ((dpc >> 4) & 0x1)
+#define NVME_ID_NS_DPC_FIRST_EIGHT(dpc)     ((dpc >> 3) & 0x1)
+#define NVME_ID_NS_DPC_TYPE_3(dpc)          ((dpc >> 2) & 0x1)
+#define NVME_ID_NS_DPC_TYPE_2(dpc)          ((dpc >> 1) & 0x1)
+#define NVME_ID_NS_DPC_TYPE_1(dpc)          ((dpc & 0x1))
+#define NVME_ID_NS_DPC_TYPE_MASK            0x7
+
+enum NvmeIdNsDps {
+    DPS_TYPE_NONE   = 0,
+    DPS_TYPE_1      = 1,
+    DPS_TYPE_2      = 2,
+    DPS_TYPE_3      = 3,
+    DPS_TYPE_MASK   = 0x7,
+    DPS_FIRST_EIGHT = 8,
+};
+
+static inline void _nvme_check_size(void)
+{
+    QEMU_BUILD_BUG_ON(sizeof(NvmeAerResult) != 4);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeCqe) != 16);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeDsmRange) != 16);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeCmd) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeDeleteQ) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeCreateCq) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeCreateSq) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeIdentify) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeRwCmd) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeDsmCmd) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeRangeType) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeErrorLog) != 64);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeFwSlotInfoLog) != 512);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeSmartLog) != 512);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeIdCtrl) != 4096);
+    QEMU_BUILD_BUG_ON(sizeof(NvmeIdNs) != 4096);
+}
+#endif
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 5fcc4f7..2cbe6a4 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -114,5 +114,44 @@
 #ifndef __has_feature
 #define __has_feature(x) 0 /* compatibility with non-clang compilers */
 #endif
+/* Implement C11 _Generic via GCC builtins.  Example:
+ *
+ *    QEMU_GENERIC(x, (float, sinf), (long double, sinl), sin) (x)
+ *
+ * The first argument is the discriminator.  The last is the default value.
+ * The middle ones are tuples in "(type, expansion)" format.
+ */
+
+/* First, find out the number of generic cases.  */
+#define QEMU_GENERIC(x, ...) \
+    QEMU_GENERIC_(typeof(x), __VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+
+/* There will be extra arguments, but they are not used.  */
+#define QEMU_GENERIC_(x, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, count, ...) \
+    QEMU_GENERIC##count(x, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9)
+
+/* Two more helper macros, this time to extract items from a parenthesized
+ * list.
+ */
+#define QEMU_FIRST_(a, b) a
+#define QEMU_SECOND_(a, b) b
+
+/* ... and a final one for the common part of the "recursion".  */
+#define QEMU_GENERIC_IF(x, type_then, else_)                                   \
+    __builtin_choose_expr(__builtin_types_compatible_p(x,                      \
+                                                       QEMU_FIRST_ type_then), \
+                          QEMU_SECOND_ type_then, else_)
+
+/* CPP poor man's "recursion".  */
+#define QEMU_GENERIC1(x, a0, ...) (a0)
+#define QEMU_GENERIC2(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC1(x, __VA_ARGS__))
+#define QEMU_GENERIC3(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC2(x, __VA_ARGS__))
+#define QEMU_GENERIC4(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC3(x, __VA_ARGS__))
+#define QEMU_GENERIC5(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC4(x, __VA_ARGS__))
+#define QEMU_GENERIC6(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC5(x, __VA_ARGS__))
+#define QEMU_GENERIC7(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC6(x, __VA_ARGS__))
+#define QEMU_GENERIC8(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC7(x, __VA_ARGS__))
+#define QEMU_GENERIC9(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC8(x, __VA_ARGS__))
+#define QEMU_GENERIC10(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC9(x, __VA_ARGS__))
 
 #endif /* COMPILER_H */
diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index ce2eb73..6f8a487 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -121,7 +121,7 @@ bool qemu_coroutine_entered(Coroutine *co);
  * Provides a mutex that can be used to synchronise coroutines
  */
 struct CoWaitRecord;
-typedef struct CoMutex {
+struct CoMutex {
     /* Count of pending lockers; 0 for a free mutex, 1 for an
      * uncontended mutex.
      */
@@ -142,7 +142,7 @@ typedef struct CoMutex {
     unsigned handoff, sequence;
 
     Coroutine *holder;
-} CoMutex;
+};
 
 /**
  * Initialises a CoMutex. This must be called before any other operation is used
@@ -183,24 +183,33 @@ void qemu_co_queue_init(CoQueue *queue);
  * caller of the coroutine.  The mutex is unlocked during the wait and
  * locked again afterwards.
  */
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex);
+#define qemu_co_queue_wait(queue, lock) \
+    qemu_co_queue_wait_impl(queue, QEMU_MAKE_LOCKABLE(lock))
+void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock);
 
 /**
- * Restarts the next coroutine in the CoQueue and removes it from the queue.
- *
- * Returns true if a coroutine was restarted, false if the queue is empty.
+ * Removes the next coroutine from the CoQueue, and wake it up.
+ * Returns true if a coroutine was removed, false if the queue is empty.
  */
 bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
 
 /**
- * Restarts all coroutines in the CoQueue and leaves the queue empty.
+ * Empties the CoQueue; all coroutines are woken up.
  */
 void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
 
 /**
- * Enter the next coroutine in the queue
+ * Removes the next coroutine from the CoQueue, and wake it up.  Unlike
+ * qemu_co_queue_next, this function releases the lock during aio_co_wake
+ * because it is meant to be used outside coroutine context; in that case, the
+ * coroutine is entered immediately, before qemu_co_enter_next returns.
+ *
+ * If used in coroutine context, qemu_co_enter_next is equivalent to
+ * qemu_co_queue_next.
  */
-bool qemu_co_enter_next(CoQueue *queue);
+#define qemu_co_enter_next(queue, lock) \
+    qemu_co_enter_next_impl(queue, QEMU_MAKE_LOCKABLE(lock))
+bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock);
 
 /**
  * Checks if the CoQueue is empty.
@@ -271,4 +280,6 @@ void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns);
  */
 void coroutine_fn yield_until_fd_readable(int fd);
 
+#include "qemu/lockable.h"
+
 #endif /* QEMU_COROUTINE_H */
diff --git a/include/qemu/lockable.h b/include/qemu/lockable.h
new file mode 100644
index 0000000..b6ed6c8
--- /dev/null
+++ b/include/qemu/lockable.h
@@ -0,0 +1,96 @@
+/*
+ * Polymorphic locking functions (aka poor man templates)
+ *
+ * Copyright Red Hat, Inc. 2017, 2018
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_LOCKABLE_H
+#define QEMU_LOCKABLE_H
+
+#include "qemu/coroutine.h"
+#include "qemu/thread.h"
+
+typedef void QemuLockUnlockFunc(void *);
+
+struct QemuLockable {
+    void *object;
+    QemuLockUnlockFunc *lock;
+    QemuLockUnlockFunc *unlock;
+};
+
+/* This function gives an error if an invalid, non-NULL pointer type is passed
+ * to QEMU_MAKE_LOCKABLE.  For optimized builds, we can rely on dead-code elimination
+ * from the compiler, and give the errors already at link time.
+ */
+#ifdef __OPTIMIZE__
+void unknown_lock_type(void *);
+#else
+static inline void unknown_lock_type(void *unused)
+{
+    abort();
+}
+#endif
+
+static inline __attribute__((__always_inline__)) QemuLockable *
+qemu_make_lockable(void *x, QemuLockable *lockable)
+{
+    /* We cannot test this in a macro, otherwise we get compiler
+     * warnings like "the address of 'm' will always evaluate as 'true'".
+     */
+    return x ? lockable : NULL;
+}
+
+/* Auxiliary macros to simplify QEMU_MAKE_LOCABLE.  */
+#define QEMU_LOCK_FUNC(x) ((QemuLockUnlockFunc *)    \
+    QEMU_GENERIC(x,                                  \
+                 (QemuMutex *, qemu_mutex_lock),     \
+                 (CoMutex *, qemu_co_mutex_lock),    \
+                 (QemuSpin *, qemu_spin_lock),       \
+                 unknown_lock_type))
+
+#define QEMU_UNLOCK_FUNC(x) ((QemuLockUnlockFunc *)  \
+    QEMU_GENERIC(x,                                  \
+                 (QemuMutex *, qemu_mutex_unlock),   \
+                 (CoMutex *, qemu_co_mutex_unlock),  \
+                 (QemuSpin *, qemu_spin_unlock),     \
+                 unknown_lock_type))
+
+/* In C, compound literals have the lifetime of an automatic variable.
+ * In C++ it would be different, but then C++ wouldn't need QemuLockable
+ * either...
+ */
+#define QEMU_MAKE_LOCKABLE_(x) qemu_make_lockable((x), &(QemuLockable) {    \
+        .object = (x),                               \
+        .lock = QEMU_LOCK_FUNC(x),                   \
+        .unlock = QEMU_UNLOCK_FUNC(x),               \
+    })
+
+/* QEMU_MAKE_LOCKABLE - Make a polymorphic QemuLockable
+ *
+ * @x: a lock object (currently one of QemuMutex, CoMutex, QemuSpin).
+ *
+ * Returns a QemuLockable object that can be passed around
+ * to a function that can operate with locks of any kind.
+ */
+#define QEMU_MAKE_LOCKABLE(x)                        \
+    QEMU_GENERIC(x,                                  \
+                 (QemuLockable *, (x)),              \
+                 QEMU_MAKE_LOCKABLE_(x))
+
+static inline void qemu_lockable_lock(QemuLockable *x)
+{
+    x->lock(x->object);
+}
+
+static inline void qemu_lockable_unlock(QemuLockable *x)
+{
+    x->unlock(x->object);
+}
+
+#endif
diff --git a/include/qemu/thread.h b/include/qemu/thread.h
index 9af4e94..ef7bd16 100644
--- a/include/qemu/thread.h
+++ b/include/qemu/thread.h
@@ -4,7 +4,6 @@
 #include "qemu/processor.h"
 #include "qemu/atomic.h"
 
-typedef struct QemuMutex QemuMutex;
 typedef struct QemuCond QemuCond;
 typedef struct QemuSemaphore QemuSemaphore;
 typedef struct QemuEvent QemuEvent;
@@ -97,9 +96,9 @@ struct Notifier;
 void qemu_thread_atexit_add(struct Notifier *notifier);
 void qemu_thread_atexit_remove(struct Notifier *notifier);
 
-typedef struct QemuSpin {
+struct QemuSpin {
     int value;
-} QemuSpin;
+};
 
 static inline void qemu_spin_init(QemuSpin *spin)
 {
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 9bd7a83..5923849 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -19,6 +19,7 @@ typedef struct BusClass BusClass;
 typedef struct BusState BusState;
 typedef struct Chardev Chardev;
 typedef struct CompatProperty CompatProperty;
+typedef struct CoMutex CoMutex;
 typedef struct CPUAddressSpace CPUAddressSpace;
 typedef struct CPUState CPUState;
 typedef struct DeviceListener DeviceListener;
@@ -86,9 +87,12 @@ typedef struct QEMUBH QEMUBH;
 typedef struct QemuConsole QemuConsole;
 typedef struct QemuDmaBuf QemuDmaBuf;
 typedef struct QEMUFile QEMUFile;
+typedef struct QemuLockable QemuLockable;
+typedef struct QemuMutex QemuMutex;
 typedef struct QemuOpt QemuOpt;
 typedef struct QemuOpts QemuOpts;
 typedef struct QemuOptsList QemuOptsList;
+typedef struct QemuSpin QemuSpin;
 typedef struct QEMUSGList QEMUSGList;
 typedef struct QEMUTimer QEMUTimer;
 typedef struct QEMUTimerListGroup QEMUTimerListGroup;
diff --git a/include/qemu/vfio-helpers.h b/include/qemu/vfio-helpers.h
new file mode 100644
index 0000000..ce7e7b0
--- /dev/null
+++ b/include/qemu/vfio-helpers.h
@@ -0,0 +1,33 @@
+/*
+ * QEMU VFIO helpers
+ *
+ * Copyright 2016 - 2018 Red Hat, Inc.
+ *
+ * Authors:
+ *   Fam Zheng <famz@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef QEMU_VFIO_HELPERS_H
+#define QEMU_VFIO_HELPERS_H
+#include "qemu/typedefs.h"
+
+typedef struct QEMUVFIOState QEMUVFIOState;
+
+QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp);
+void qemu_vfio_close(QEMUVFIOState *s);
+int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
+                      bool temporary, uint64_t *iova_list);
+int qemu_vfio_dma_reset_temporary(QEMUVFIOState *s);
+void qemu_vfio_dma_unmap(QEMUVFIOState *s, void *host);
+void *qemu_vfio_pci_map_bar(QEMUVFIOState *s, int index,
+                            uint64_t offset, uint64_t size,
+                            Error **errp);
+void qemu_vfio_pci_unmap_bar(QEMUVFIOState *s, int index, void *bar,
+                             uint64_t offset, uint64_t size);
+int qemu_vfio_pci_init_irq(QEMUVFIOState *s, EventNotifier *e,
+                           int irq_type, Error **errp);
+
+#endif
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index c4e52a5..92ab624 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -229,4 +229,7 @@ void blk_io_limits_enable(BlockBackend *blk, const char *group);
 void blk_io_limits_update_group(BlockBackend *blk, const char *group);
 void blk_set_force_allow_inactivate(BlockBackend *blk);
 
+void blk_register_buf(BlockBackend *blk, void *host, size_t size);
+void blk_unregister_buf(BlockBackend *blk, void *host);
+
 #endif
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 8225308..8046c2d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2248,6 +2248,7 @@
 #
 # @vxhs: Since 2.10
 # @throttle: Since 2.11
+# @nvme: Since 2.12
 #
 # Since: 2.9
 ##
@@ -2255,7 +2256,7 @@
   'data': [ 'blkdebug', 'blkverify', 'bochs', 'cloop',
             'dmg', 'file', 'ftp', 'ftps', 'gluster', 'host_cdrom',
             'host_device', 'http', 'https', 'iscsi', 'luks', 'nbd', 'nfs',
-            'null-aio', 'null-co', 'parallels', 'qcow', 'qcow2', 'qed',
+            'null-aio', 'null-co', 'nvme', 'parallels', 'qcow', 'qcow2', 'qed',
             'quorum', 'raw', 'rbd', 'replication', 'sheepdog', 'ssh',
             'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat', 'vxhs' ] }
 
@@ -2297,6 +2298,19 @@
   'data': { '*size': 'int', '*latency-ns': 'uint64' } }
 
 ##
+# @BlockdevOptionsNVMe:
+#
+# Driver specific block device options for the NVMe backend.
+#
+# @device:    controller address of the NVMe device.
+# @namespace: namespace number of the device, starting from 1.
+#
+# Since: 2.12
+##
+{ 'struct': 'BlockdevOptionsNVMe',
+  'data': { 'device': 'str', 'namespace': 'int' } }
+
+##
 # @BlockdevOptionsVVFAT:
 #
 # Driver specific block device options for the vvfat protocol.
@@ -3201,6 +3215,7 @@
       'nfs':        'BlockdevOptionsNfs',
       'null-aio':   'BlockdevOptionsNull',
       'null-co':    'BlockdevOptionsNull',
+      'nvme':       'BlockdevOptionsNVMe',
       'parallels':  'BlockdevOptionsGenericFormat',
       'qcow2':      'BlockdevOptionsQcow2',
       'qcow':       'BlockdevOptionsQcow',
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 19a82bf..769968a 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -621,6 +621,7 @@ encrypted disk images.
 * disk_images_iscsi::         iSCSI LUNs
 * disk_images_gluster::       GlusterFS disk images
 * disk_images_ssh::           Secure Shell (ssh) disk images
+* disk_images_nvme::          NVMe userspace driver
 * disk_image_locking::        Disk image file locking
 @end menu
 
diff --git a/qemu-img.c b/qemu-img.c
index 68b375f..28d0e4e 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3862,6 +3862,7 @@ static int img_bench(int argc, char **argv)
     struct timeval t1, t2;
     int i;
     bool force_share = false;
+    size_t buf_size;
 
     for (;;) {
         static const struct option long_options[] = {
@@ -4050,9 +4051,12 @@ static int img_bench(int argc, char **argv)
         printf("Sending flush every %d requests\n", flush_interval);
     }
 
-    data.buf = blk_blockalign(blk, data.nrreq * data.bufsize);
+    buf_size = data.nrreq * data.bufsize;
+    data.buf = blk_blockalign(blk, buf_size);
     memset(data.buf, pattern, data.nrreq * data.bufsize);
 
+    blk_register_buf(blk, data.buf, buf_size);
+
     data.qiov = g_new(QEMUIOVector, data.nrreq);
     for (i = 0; i < data.nrreq; i++) {
         qemu_iovec_init(&data.qiov[i], 1);
@@ -4073,6 +4077,9 @@ static int img_bench(int argc, char **argv)
            + ((double)(t2.tv_usec - t1.tv_usec) / 1000000));
 
 out:
+    if (data.buf) {
+        blk_unregister_buf(blk, data.buf);
+    }
     qemu_vfree(data.buf);
     blk_unref(blk);
 
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index 8cfe343..2d59d84 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -42,3 +42,4 @@ stub-obj-y += vmgenid.o
 stub-obj-y += xen-common.o
 stub-obj-y += xen-hvm.o
 stub-obj-y += pci-host-piix.o
+stub-obj-y += ram-block.o
diff --git a/stubs/ram-block.c b/stubs/ram-block.c
new file mode 100644
index 0000000..cfa5d86
--- /dev/null
+++ b/stubs/ram-block.c
@@ -0,0 +1,16 @@
+#include "qemu/osdep.h"
+#include "exec/ramlist.h"
+#include "exec/cpu-common.h"
+
+void ram_block_notifier_add(RAMBlockNotifier *n)
+{
+}
+
+void ram_block_notifier_remove(RAMBlockNotifier *n)
+{
+}
+
+int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque)
+{
+    return 0;
+}
diff --git a/tests/docker/dockerfiles/fedora.docker b/tests/docker/dockerfiles/fedora.docker
index 26ede4f..994a35a 100644
--- a/tests/docker/dockerfiles/fedora.docker
+++ b/tests/docker/dockerfiles/fedora.docker
@@ -1,4 +1,4 @@
-FROM fedora:latest
+FROM fedora:27
 ENV PACKAGES \
     ccache gettext git tar PyYAML sparse flex bison python3 bzip2 hostname \
     glib2-devel pixman-devel zlib-devel SDL-devel libfdt-devel \
diff --git a/tests/test-coroutine.c b/tests/test-coroutine.c
index 76c6461..28e79b3 100644
--- a/tests/test-coroutine.c
+++ b/tests/test-coroutine.c
@@ -14,6 +14,7 @@
 #include "qemu/osdep.h"
 #include "qemu/coroutine.h"
 #include "qemu/coroutine_int.h"
+#include "qemu/lockable.h"
 
 /*
  * Check that qemu_in_coroutine() works
@@ -175,7 +176,7 @@ static void coroutine_fn c1_fn(void *opaque)
     qemu_coroutine_enter(c2);
 }
 
-static void test_co_queue(void)
+static void test_no_dangling_access(void)
 {
     Coroutine *c1;
     Coroutine *c2;
@@ -195,6 +196,74 @@ static void test_co_queue(void)
     *c1 = tmp;
 }
 
+static bool locked;
+static int done;
+
+static void coroutine_fn mutex_fn(void *opaque)
+{
+    CoMutex *m = opaque;
+    qemu_co_mutex_lock(m);
+    assert(!locked);
+    locked = true;
+    qemu_coroutine_yield();
+    locked = false;
+    qemu_co_mutex_unlock(m);
+    done++;
+}
+
+static void coroutine_fn lockable_fn(void *opaque)
+{
+    QemuLockable *x = opaque;
+    qemu_lockable_lock(x);
+    assert(!locked);
+    locked = true;
+    qemu_coroutine_yield();
+    locked = false;
+    qemu_lockable_unlock(x);
+    done++;
+}
+
+static void do_test_co_mutex(CoroutineEntry *entry, void *opaque)
+{
+    Coroutine *c1 = qemu_coroutine_create(entry, opaque);
+    Coroutine *c2 = qemu_coroutine_create(entry, opaque);
+
+    done = 0;
+    qemu_coroutine_enter(c1);
+    g_assert(locked);
+    qemu_coroutine_enter(c2);
+
+    /* Unlock queues c2.  It is then started automatically when c1 yields or
+     * terminates.
+     */
+    qemu_coroutine_enter(c1);
+    g_assert_cmpint(done, ==, 1);
+    g_assert(locked);
+
+    qemu_coroutine_enter(c2);
+    g_assert_cmpint(done, ==, 2);
+    g_assert(!locked);
+}
+
+static void test_co_mutex(void)
+{
+    CoMutex m;
+
+    qemu_co_mutex_init(&m);
+    do_test_co_mutex(mutex_fn, &m);
+}
+
+static void test_co_mutex_lockable(void)
+{
+    CoMutex m;
+    CoMutex *null_pointer = NULL;
+
+    qemu_co_mutex_init(&m);
+    do_test_co_mutex(lockable_fn, QEMU_MAKE_LOCKABLE(&m));
+
+    g_assert(QEMU_MAKE_LOCKABLE(null_pointer) == NULL);
+}
+
 /*
  * Check that creation, enter, and return work
  */
@@ -422,7 +491,7 @@ int main(int argc, char **argv)
      * crash, so skip it.
      */
     if (CONFIG_COROUTINE_POOL) {
-        g_test_add_func("/basic/co_queue", test_co_queue);
+        g_test_add_func("/basic/no-dangling-access", test_no_dangling_access);
     }
 
     g_test_add_func("/basic/lifecycle", test_lifecycle);
@@ -432,6 +501,8 @@ int main(int argc, char **argv)
     g_test_add_func("/basic/entered", test_entered);
     g_test_add_func("/basic/in_coroutine", test_in_coroutine);
     g_test_add_func("/basic/order", test_order);
+    g_test_add_func("/locking/co-mutex", test_co_mutex);
+    g_test_add_func("/locking/co-mutex/lockable", test_co_mutex_lockable);
     if (g_test_perf()) {
         g_test_add_func("/perf/lifecycle", perf_lifecycle);
         g_test_add_func("/perf/nesting", perf_nesting);
diff --git a/tests/vm/README b/tests/vm/README
index ae53dce..f9c04cc 100644
--- a/tests/vm/README
+++ b/tests/vm/README
@@ -1,89 +1 @@
-=== VM test suite to run build in guests ===
-
-== Intro ==
-
-This test suite contains scripts that bootstrap various guest images that have
-necessary packages to build QEMU. The basic usage is documented in Makefile
-help which is displayed with "make vm-test".
-
-== Quick start ==
-
-Run "make vm-test" to list available make targets. Invoke a specific make
-command to run build test in an image. For example, "make vm-build-freebsd"
-will build the source tree in the FreeBSD image. The command can be executed
-from either the source tree or the build dir; if the former, ./configure is not
-needed. The command will then generate the test image in ./tests/vm/ under the
-working directory.
-
-Note: images created by the scripts accept a well-known RSA key pair for SSH
-access, so they SHOULD NOT be exposed to external interfaces if you are
-concerned about attackers taking control of the guest and potentially
-exploiting a QEMU security bug to compromise the host.
-
-== QEMU binary ==
-
-By default, qemu-system-x86_64 is searched in $PATH to run the guest. If there
-isn't one, or if it is older than 2.10, the test won't work. In this case,
-provide the QEMU binary in env var: QEMU=/path/to/qemu-2.10+.
-
-== Make jobs ==
-
-The "-j$X" option in the make command line is not propagated into the VM,
-specify "J=$X" to control the make jobs in the guest.
-
-== Debugging ==
-
-Add "DEBUG=1" and/or "V=1" to the make command to allow interactive debugging
-and verbose output. If this is not enough, see the next section.
-
-== Manual invocation ==
-
-Each guest script is an executable script with the same command line options.
-For example to work with the netbsd guest, use $QEMU_SRC/tests/vm/netbsd:
-
-    $ cd $QEMU_SRC/tests/vm
-
-    # To bootstrap the image
-    $ ./netbsd --build-image --image /var/tmp/netbsd.img
-    <...>
-
-    # To run an arbitrary command in guest (the output will not be echoed unless
-    # --debug is added)
-    $ ./netbsd --debug --image /var/tmp/netbsd.img uname -a
-
-    # To build QEMU in guest
-    $ ./netbsd --debug --image /var/tmp/netbsd.img --build-qemu $QEMU_SRC
-
-    # To get to an interactive shell
-    $ ./netbsd --interactive --image /var/tmp/netbsd.img sh
-
-== Adding new guests ==
-
-Please look at existing guest scripts for how to add new guests.
-
-Most importantly, create a subclass of BaseVM and implement build_image()
-method and define BUILD_SCRIPT, then finally call basevm.main() from the
-script's main().
-
-  - Usually in build_image(), a template image is downloaded from a predefined
-    URL. BaseVM._download_with_cache() takes care of the cache and the
-    checksum, so consider using it.
-
-  - Once the image is downloaded, users, SSH server and QEMU build deps should
-    be set up:
-
-    * Root password set to BaseVM.ROOT_PASS
-    * User BaseVM.GUEST_USER is created, and password set to BaseVM.GUEST_PASS
-    * SSH service is enabled and started on boot,
-      $QEMU_SRC/tests/keys/id_rsa.pub is added to ssh's "authorized_keys" file
-      of both root and the normal user
-    * DHCP client service is enabled and started on boot, so that it can
-      automatically configure the virtio-net-pci NIC and communicate with QEMU
-      user net (10.0.2.2)
-    * Necessary packages are installed to untar the source tarball and build
-      QEMU
-
-  - Write a proper BUILD_SCRIPT template, which should be a shell script that
-    untars a raw virtio-blk block device, which is the tarball data blob of the
-    QEMU source tree, then configure/build it. Running "make check" is also
-    recommended.
+See docs/devel/testing.rst for help.
diff --git a/util/Makefile.objs b/util/Makefile.objs
index 2973b0a..3fb6116 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -46,3 +46,4 @@ util-obj-y += qht.o
 util-obj-y += range.o
 util-obj-y += stats64.o
 util-obj-y += systemd.o
+util-obj-$(CONFIG_LINUX) += vfio-helpers.o
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 846ff91..78fb79a 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -40,13 +40,13 @@ void qemu_co_queue_init(CoQueue *queue)
     QSIMPLEQ_INIT(&queue->entries);
 }
 
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
+void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock)
 {
     Coroutine *self = qemu_coroutine_self();
     QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
 
-    if (mutex) {
-        qemu_co_mutex_unlock(mutex);
+    if (lock) {
+        qemu_lockable_unlock(lock);
     }
 
     /* There is no race condition here.  Other threads will call
@@ -60,9 +60,11 @@ void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
     /* TODO: OSv implements wait morphing here, where the wakeup
      * primitive automatically places the woken coroutine on the
      * mutex's queue.  This avoids the thundering herd effect.
+     * This could be implemented for CoMutexes, but not really for
+     * other cases of QemuLockable.
      */
-    if (mutex) {
-        qemu_co_mutex_lock(mutex);
+    if (lock) {
+        qemu_lockable_lock(lock);
     }
 }
 
@@ -130,7 +132,7 @@ void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
     qemu_co_queue_do_restart(queue, false);
 }
 
-bool qemu_co_enter_next(CoQueue *queue)
+bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock)
 {
     Coroutine *next;
 
@@ -140,7 +142,13 @@ bool qemu_co_enter_next(CoQueue *queue)
     }
 
     QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next);
-    qemu_coroutine_enter(next);
+    if (lock) {
+        qemu_lockable_unlock(lock);
+    }
+    aio_co_wake(next);
+    if (lock) {
+        qemu_lockable_lock(lock);
+    }
     return true;
 }
 
diff --git a/util/trace-events b/util/trace-events
index 515e625..4822434 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -60,3 +60,14 @@ lockcnt_futex_wake(const void *lockcnt) "lockcnt %p waking up one waiter"
 qemu_mutex_lock(void *mutex, const char *file, const int line) "waiting on mutex %p (%s:%d)"
 qemu_mutex_locked(void *mutex, const char *file, const int line) "taken mutex %p (%s:%d)"
 qemu_mutex_unlock(void *mutex, const char *file, const int line) "released mutex %p (%s:%d)"
+
+# util/vfio-helpers.c
+qemu_vfio_dma_reset_temporary(void *s) "s %p"
+qemu_vfio_ram_block_added(void *s, void *p, size_t size) "s %p host %p size 0x%zx"
+qemu_vfio_ram_block_removed(void *s, void *p, size_t size) "s %p host %p size 0x%zx"
+qemu_vfio_find_mapping(void *s, void *p) "s %p host %p"
+qemu_vfio_new_mapping(void *s, void *host, size_t size, int index, uint64_t iova) "s %p host %p size %zu index %d iova 0x%"PRIx64
+qemu_vfio_do_mapping(void *s, void *host, size_t size, uint64_t iova) "s %p host %p size %zu iova 0x%"PRIx64
+qemu_vfio_dma_map(void *s, void *host, size_t size, bool temporary, uint64_t *iova) "s %p host %p size %zu temporary %d iova %p"
+qemu_vfio_dma_map_invalid(void *s, void *mapping_host, size_t mapping_size, void *host, size_t size) "s %p mapping %p %zu requested %p %zu"
+qemu_vfio_dma_unmap(void *s, void *host) "s %p host %p"
diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
new file mode 100644
index 0000000..f478b68
--- /dev/null
+++ b/util/vfio-helpers.c
@@ -0,0 +1,727 @@
+/*
+ * VFIO utility
+ *
+ * Copyright 2016 - 2018 Red Hat, Inc.
+ *
+ * Authors:
+ *   Fam Zheng <famz@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include <sys/ioctl.h>
+#include <linux/vfio.h>
+#include "qapi/error.h"
+#include "exec/ramlist.h"
+#include "exec/cpu-common.h"
+#include "trace.h"
+#include "qemu/queue.h"
+#include "qemu/error-report.h"
+#include "standard-headers/linux/pci_regs.h"
+#include "qemu/event_notifier.h"
+#include "qemu/vfio-helpers.h"
+#include "trace.h"
+
+#define QEMU_VFIO_DEBUG 0
+
+#define QEMU_VFIO_IOVA_MIN 0x10000ULL
+/* XXX: Once VFIO exposes the iova bit width in the IOMMU capability interface,
+ * we can use a runtime limit; alternatively it's also possible to do platform
+ * specific detection by reading sysfs entries. Until then, 39 is a safe bet.
+ **/
+#define QEMU_VFIO_IOVA_MAX (1ULL << 39)
+
+typedef struct {
+    /* Page aligned addr. */
+    void *host;
+    size_t size;
+    uint64_t iova;
+} IOVAMapping;
+
+struct QEMUVFIOState {
+    QemuMutex lock;
+
+    /* These fields are protected by BQL */
+    int container;
+    int group;
+    int device;
+    RAMBlockNotifier ram_notifier;
+    struct vfio_region_info config_region_info, bar_region_info[6];
+
+    /* These fields are protected by @lock */
+    /* VFIO's IO virtual address space is managed by splitting into a few
+     * sections:
+     *
+     * ---------------       <= 0
+     * |xxxxxxxxxxxxx|
+     * |-------------|       <= QEMU_VFIO_IOVA_MIN
+     * |             |
+     * |    Fixed    |
+     * |             |
+     * |-------------|       <= low_water_mark
+     * |             |
+     * |    Free     |
+     * |             |
+     * |-------------|       <= high_water_mark
+     * |             |
+     * |    Temp     |
+     * |             |
+     * |-------------|       <= QEMU_VFIO_IOVA_MAX
+     * |xxxxxxxxxxxxx|
+     * |xxxxxxxxxxxxx|
+     * ---------------
+     *
+     * - Addresses lower than QEMU_VFIO_IOVA_MIN are reserved as invalid;
+     *
+     * - Fixed mappings of HVAs are assigned "low" IOVAs in the range of
+     *   [QEMU_VFIO_IOVA_MIN, low_water_mark).  Once allocated they will not be
+     *   reclaimed - low_water_mark never shrinks;
+     *
+     * - IOVAs in range [low_water_mark, high_water_mark) are free;
+     *
+     * - IOVAs in range [high_water_mark, QEMU_VFIO_IOVA_MAX) are volatile
+     *   mappings. At each qemu_vfio_dma_reset_temporary() call, the whole area
+     *   is recycled. The caller should make sure I/O's depending on these
+     *   mappings are completed before calling.
+     **/
+    uint64_t low_water_mark;
+    uint64_t high_water_mark;
+    IOVAMapping *mappings;
+    int nr_mappings;
+};
+
+/**
+ * Find group file by PCI device address as specified @device, and return the
+ * path. The returned string is owned by caller and should be g_free'ed later.
+ */
+static char *sysfs_find_group_file(const char *device, Error **errp)
+{
+    char *sysfs_link;
+    char *sysfs_group;
+    char *p;
+    char *path = NULL;
+
+    sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
+    sysfs_group = g_malloc(PATH_MAX);
+    if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
+        error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
+        goto out;
+    }
+    p = strrchr(sysfs_group, '/');
+    if (!p) {
+        error_setg(errp, "Failed to find iommu group number");
+        goto out;
+    }
+
+    path = g_strdup_printf("/dev/vfio/%s", p + 1);
+out:
+    g_free(sysfs_link);
+    g_free(sysfs_group);
+    return path;
+}
+
+static inline void assert_bar_index_valid(QEMUVFIOState *s, int index)
+{
+    assert(index >= 0 && index < ARRAY_SIZE(s->bar_region_info));
+}
+
+static int qemu_vfio_pci_init_bar(QEMUVFIOState *s, int index, Error **errp)
+{
+    assert_bar_index_valid(s, index);
+    s->bar_region_info[index] = (struct vfio_region_info) {
+        .index = VFIO_PCI_BAR0_REGION_INDEX + index,
+        .argsz = sizeof(struct vfio_region_info),
+    };
+    if (ioctl(s->device, VFIO_DEVICE_GET_REGION_INFO, &s->bar_region_info[index])) {
+        error_setg_errno(errp, errno, "Failed to get BAR region info");
+        return -errno;
+    }
+
+    return 0;
+}
+
+/**
+ * Map a PCI bar area.
+ */
+void *qemu_vfio_pci_map_bar(QEMUVFIOState *s, int index,
+                            uint64_t offset, uint64_t size,
+                            Error **errp)
+{
+    void *p;
+    assert_bar_index_valid(s, index);
+    p = mmap(NULL, MIN(size, s->bar_region_info[index].size - offset),
+             PROT_READ | PROT_WRITE, MAP_SHARED,
+             s->device, s->bar_region_info[index].offset + offset);
+    if (p == MAP_FAILED) {
+        error_setg_errno(errp, errno, "Failed to map BAR region");
+        p = NULL;
+    }
+    return p;
+}
+
+/**
+ * Unmap a PCI bar area.
+ */
+void qemu_vfio_pci_unmap_bar(QEMUVFIOState *s, int index, void *bar,
+                             uint64_t offset, uint64_t size)
+{
+    if (bar) {
+        munmap(bar, MIN(size, s->bar_region_info[index].size - offset));
+    }
+}
+
+/**
+ * Initialize device IRQ with @irq_type and and register an event notifier.
+ */
+int qemu_vfio_pci_init_irq(QEMUVFIOState *s, EventNotifier *e,
+                           int irq_type, Error **errp)
+{
+    int r;
+    struct vfio_irq_set *irq_set;
+    size_t irq_set_size;
+    struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
+
+    irq_info.index = irq_type;
+    if (ioctl(s->device, VFIO_DEVICE_GET_IRQ_INFO, &irq_info)) {
+        error_setg_errno(errp, errno, "Failed to get device interrupt info");
+        return -errno;
+    }
+    if (!(irq_info.flags & VFIO_IRQ_INFO_EVENTFD)) {
+        error_setg(errp, "Device interrupt doesn't support eventfd");
+        return -EINVAL;
+    }
+
+    irq_set_size = sizeof(*irq_set) + sizeof(int);
+    irq_set = g_malloc0(irq_set_size);
+
+    /* Get to a known IRQ state */
+    *irq_set = (struct vfio_irq_set) {
+        .argsz = irq_set_size,
+        .flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
+        .index = irq_info.index,
+        .start = 0,
+        .count = 1,
+    };
+
+    *(int *)&irq_set->data = event_notifier_get_fd(e);
+    r = ioctl(s->device, VFIO_DEVICE_SET_IRQS, irq_set);
+    g_free(irq_set);
+    if (r) {
+        error_setg_errno(errp, errno, "Failed to setup device interrupt");
+        return -errno;
+    }
+    return 0;
+}
+
+static int qemu_vfio_pci_read_config(QEMUVFIOState *s, void *buf,
+                                     int size, int ofs)
+{
+    int ret;
+
+    do {
+        ret = pread(s->device, buf, size, s->config_region_info.offset + ofs);
+    } while (ret == -1 && errno == EINTR);
+    return ret == size ? 0 : -errno;
+}
+
+static int qemu_vfio_pci_write_config(QEMUVFIOState *s, void *buf, int size, int ofs)
+{
+    int ret;
+
+    do {
+        ret = pwrite(s->device, buf, size, s->config_region_info.offset + ofs);
+    } while (ret == -1 && errno == EINTR);
+    return ret == size ? 0 : -errno;
+}
+
+static int qemu_vfio_init_pci(QEMUVFIOState *s, const char *device,
+                              Error **errp)
+{
+    int ret;
+    int i;
+    uint16_t pci_cmd;
+    struct vfio_group_status group_status = { .argsz = sizeof(group_status) };
+    struct vfio_iommu_type1_info iommu_info = { .argsz = sizeof(iommu_info) };
+    struct vfio_device_info device_info = { .argsz = sizeof(device_info) };
+    char *group_file = NULL;
+
+    /* Create a new container */
+    s->container = open("/dev/vfio/vfio", O_RDWR);
+
+    if (s->container == -1) {
+        error_setg_errno(errp, errno, "Failed to open /dev/vfio/vfio");
+        return -errno;
+    }
+    if (ioctl(s->container, VFIO_GET_API_VERSION) != VFIO_API_VERSION) {
+        error_setg(errp, "Invalid VFIO version");
+        ret = -EINVAL;
+        goto fail_container;
+    }
+
+    if (!ioctl(s->container, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
+        error_setg_errno(errp, errno, "VFIO IOMMU check failed");
+        ret = -EINVAL;
+        goto fail_container;
+    }
+
+    /* Open the group */
+    group_file = sysfs_find_group_file(device, errp);
+    if (!group_file) {
+        ret = -EINVAL;
+        goto fail_container;
+    }
+
+    s->group = open(group_file, O_RDWR);
+    if (s->group == -1) {
+        error_setg_errno(errp, errno, "Failed to open VFIO group file: %s",
+                         group_file);
+        g_free(group_file);
+        ret = -errno;
+        goto fail_container;
+    }
+    g_free(group_file);
+
+    /* Test the group is viable and available */
+    if (ioctl(s->group, VFIO_GROUP_GET_STATUS, &group_status)) {
+        error_setg_errno(errp, errno, "Failed to get VFIO group status");
+        ret = -errno;
+        goto fail;
+    }
+
+    if (!(group_status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
+        error_setg(errp, "VFIO group is not viable");
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    /* Add the group to the container */
+    if (ioctl(s->group, VFIO_GROUP_SET_CONTAINER, &s->container)) {
+        error_setg_errno(errp, errno, "Failed to add group to VFIO container");
+        ret = -errno;
+        goto fail;
+    }
+
+    /* Enable the IOMMU model we want */
+    if (ioctl(s->container, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU)) {
+        error_setg_errno(errp, errno, "Failed to set VFIO IOMMU type");
+        ret = -errno;
+        goto fail;
+    }
+
+    /* Get additional IOMMU info */
+    if (ioctl(s->container, VFIO_IOMMU_GET_INFO, &iommu_info)) {
+        error_setg_errno(errp, errno, "Failed to get IOMMU info");
+        ret = -errno;
+        goto fail;
+    }
+
+    s->device = ioctl(s->group, VFIO_GROUP_GET_DEVICE_FD, device);
+
+    if (s->device < 0) {
+        error_setg_errno(errp, errno, "Failed to get device fd");
+        ret = -errno;
+        goto fail;
+    }
+
+    /* Test and setup the device */
+    if (ioctl(s->device, VFIO_DEVICE_GET_INFO, &device_info)) {
+        error_setg_errno(errp, errno, "Failed to get device info");
+        ret = -errno;
+        goto fail;
+    }
+
+    if (device_info.num_regions < VFIO_PCI_CONFIG_REGION_INDEX) {
+        error_setg(errp, "Invalid device regions");
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    s->config_region_info = (struct vfio_region_info) {
+        .index = VFIO_PCI_CONFIG_REGION_INDEX,
+        .argsz = sizeof(struct vfio_region_info),
+    };
+    if (ioctl(s->device, VFIO_DEVICE_GET_REGION_INFO, &s->config_region_info)) {
+        error_setg_errno(errp, errno, "Failed to get config region info");
+        ret = -errno;
+        goto fail;
+    }
+
+    for (i = 0; i < 6; i++) {
+        ret = qemu_vfio_pci_init_bar(s, i, errp);
+        if (ret) {
+            goto fail;
+        }
+    }
+
+    /* Enable bus master */
+    ret = qemu_vfio_pci_read_config(s, &pci_cmd, sizeof(pci_cmd), PCI_COMMAND);
+    if (ret) {
+        goto fail;
+    }
+    pci_cmd |= PCI_COMMAND_MASTER;
+    ret = qemu_vfio_pci_write_config(s, &pci_cmd, sizeof(pci_cmd), PCI_COMMAND);
+    if (ret) {
+        goto fail;
+    }
+    return 0;
+fail:
+    close(s->group);
+fail_container:
+    close(s->container);
+    return ret;
+}
+
+static void qemu_vfio_ram_block_added(RAMBlockNotifier *n,
+                                      void *host, size_t size)
+{
+    QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
+    trace_qemu_vfio_ram_block_added(s, host, size);
+    qemu_vfio_dma_map(s, host, size, false, NULL);
+}
+
+static void qemu_vfio_ram_block_removed(RAMBlockNotifier *n,
+                                        void *host, size_t size)
+{
+    QEMUVFIOState *s = container_of(n, QEMUVFIOState, ram_notifier);
+    if (host) {
+        trace_qemu_vfio_ram_block_removed(s, host, size);
+        qemu_vfio_dma_unmap(s, host);
+    }
+}
+
+static int qemu_vfio_init_ramblock(const char *block_name, void *host_addr,
+                                   ram_addr_t offset, ram_addr_t length,
+                                   void *opaque)
+{
+    int ret;
+    QEMUVFIOState *s = opaque;
+
+    if (!host_addr) {
+        return 0;
+    }
+    ret = qemu_vfio_dma_map(s, host_addr, length, false, NULL);
+    if (ret) {
+        fprintf(stderr, "qemu_vfio_init_ramblock: failed %p %" PRId64 "\n",
+                host_addr, (uint64_t)length);
+    }
+    return 0;
+}
+
+static void qemu_vfio_open_common(QEMUVFIOState *s)
+{
+    s->ram_notifier.ram_block_added = qemu_vfio_ram_block_added;
+    s->ram_notifier.ram_block_removed = qemu_vfio_ram_block_removed;
+    ram_block_notifier_add(&s->ram_notifier);
+    s->low_water_mark = QEMU_VFIO_IOVA_MIN;
+    s->high_water_mark = QEMU_VFIO_IOVA_MAX;
+    qemu_ram_foreach_block(qemu_vfio_init_ramblock, s);
+    qemu_mutex_init(&s->lock);
+}
+
+/**
+ * Open a PCI device, e.g. "0000:00:01.0".
+ */
+QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp)
+{
+    int r;
+    QEMUVFIOState *s = g_new0(QEMUVFIOState, 1);
+
+    r = qemu_vfio_init_pci(s, device, errp);
+    if (r) {
+        g_free(s);
+        return NULL;
+    }
+    qemu_vfio_open_common(s);
+    return s;
+}
+
+static void qemu_vfio_dump_mapping(IOVAMapping *m)
+{
+    if (QEMU_VFIO_DEBUG) {
+        printf("  vfio mapping %p %" PRIx64 " to %" PRIx64 "\n", m->host,
+               (uint64_t)m->size, (uint64_t)m->iova);
+    }
+}
+
+static void qemu_vfio_dump_mappings(QEMUVFIOState *s)
+{
+    int i;
+
+    if (QEMU_VFIO_DEBUG) {
+        printf("vfio mappings\n");
+        for (i = 0; i < s->nr_mappings; ++i) {
+            qemu_vfio_dump_mapping(&s->mappings[i]);
+        }
+    }
+}
+
+/**
+ * Find the mapping entry that contains [host, host + size) and set @index to
+ * the position. If no entry contains it, @index is the position _after_ which
+ * to insert the new mapping. IOW, it is the index of the largest element that
+ * is smaller than @host, or -1 if no entry is.
+ */
+static IOVAMapping *qemu_vfio_find_mapping(QEMUVFIOState *s, void *host,
+                                           int *index)
+{
+    IOVAMapping *p = s->mappings;
+    IOVAMapping *q = p ? p + s->nr_mappings - 1 : NULL;
+    IOVAMapping *mid;
+    trace_qemu_vfio_find_mapping(s, host);
+    if (!p) {
+        *index = -1;
+        return NULL;
+    }
+    while (true) {
+        mid = p + (q - p) / 2;
+        if (mid == p) {
+            break;
+        }
+        if (mid->host > host) {
+            q = mid;
+        } else if (mid->host < host) {
+            p = mid;
+        } else {
+            break;
+        }
+    }
+    if (mid->host > host) {
+        mid--;
+    } else if (mid < &s->mappings[s->nr_mappings - 1]
+               && (mid + 1)->host <= host) {
+        mid++;
+    }
+    *index = mid - &s->mappings[0];
+    if (mid >= &s->mappings[0] &&
+        mid->host <= host && mid->host + mid->size > host) {
+        assert(mid < &s->mappings[s->nr_mappings]);
+        return mid;
+    }
+    /* At this point *index + 1 is the right position to insert the new
+     * mapping.*/
+    return NULL;
+}
+
+/**
+ * Allocate IOVA and and create a new mapping record and insert it in @s.
+ */
+static IOVAMapping *qemu_vfio_add_mapping(QEMUVFIOState *s,
+                                          void *host, size_t size,
+                                          int index, uint64_t iova)
+{
+    int shift;
+    IOVAMapping m = {.host = host, .size = size, .iova = iova};
+    IOVAMapping *insert;
+
+    assert(QEMU_IS_ALIGNED(size, getpagesize()));
+    assert(QEMU_IS_ALIGNED(s->low_water_mark, getpagesize()));
+    assert(QEMU_IS_ALIGNED(s->high_water_mark, getpagesize()));
+    trace_qemu_vfio_new_mapping(s, host, size, index, iova);
+
+    assert(index >= 0);
+    s->nr_mappings++;
+    s->mappings = g_realloc_n(s->mappings, sizeof(s->mappings[0]),
+                              s->nr_mappings);
+    insert = &s->mappings[index];
+    shift = s->nr_mappings - index - 1;
+    if (shift) {
+        memmove(insert + 1, insert, shift * sizeof(s->mappings[0]));
+    }
+    *insert = m;
+    return insert;
+}
+
+/* Do the DMA mapping with VFIO. */
+static int qemu_vfio_do_mapping(QEMUVFIOState *s, void *host, size_t size,
+                                uint64_t iova)
+{
+    struct vfio_iommu_type1_dma_map dma_map = {
+        .argsz = sizeof(dma_map),
+        .flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
+        .iova = iova,
+        .vaddr = (uintptr_t)host,
+        .size = size,
+    };
+    trace_qemu_vfio_do_mapping(s, host, size, iova);
+
+    if (ioctl(s->container, VFIO_IOMMU_MAP_DMA, &dma_map)) {
+        error_report("VFIO_MAP_DMA: %d", -errno);
+        return -errno;
+    }
+    return 0;
+}
+
+/**
+ * Undo the DMA mapping from @s with VFIO, and remove from mapping list.
+ */
+static void qemu_vfio_undo_mapping(QEMUVFIOState *s, IOVAMapping *mapping,
+                                   Error **errp)
+{
+    int index;
+    struct vfio_iommu_type1_dma_unmap unmap = {
+        .argsz = sizeof(unmap),
+        .flags = 0,
+        .iova = mapping->iova,
+        .size = mapping->size,
+    };
+
+    index = mapping - s->mappings;
+    assert(mapping->size > 0);
+    assert(QEMU_IS_ALIGNED(mapping->size, getpagesize()));
+    assert(index >= 0 && index < s->nr_mappings);
+    if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
+        error_setg(errp, "VFIO_UNMAP_DMA failed: %d", -errno);
+    }
+    memmove(mapping, &s->mappings[index + 1],
+            sizeof(s->mappings[0]) * (s->nr_mappings - index - 1));
+    s->nr_mappings--;
+    s->mappings = g_realloc_n(s->mappings, sizeof(s->mappings[0]),
+                              s->nr_mappings);
+}
+
+/* Check if the mapping list is (ascending) ordered. */
+static bool qemu_vfio_verify_mappings(QEMUVFIOState *s)
+{
+    int i;
+    if (QEMU_VFIO_DEBUG) {
+        for (i = 0; i < s->nr_mappings - 1; ++i) {
+            if (!(s->mappings[i].host < s->mappings[i + 1].host)) {
+                fprintf(stderr, "item %d not sorted!\n", i);
+                qemu_vfio_dump_mappings(s);
+                return false;
+            }
+            if (!(s->mappings[i].host + s->mappings[i].size <=
+                  s->mappings[i + 1].host)) {
+                fprintf(stderr, "item %d overlap with next!\n", i);
+                qemu_vfio_dump_mappings(s);
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+/* Map [host, host + size) area into a contiguous IOVA address space, and store
+ * the result in @iova if not NULL. The caller need to make sure the area is
+ * aligned to page size, and mustn't overlap with existing mapping areas (split
+ * mapping status within this area is not allowed).
+ */
+int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
+                      bool temporary, uint64_t *iova)
+{
+    int ret = 0;
+    int index;
+    IOVAMapping *mapping;
+    uint64_t iova0;
+
+    assert(QEMU_PTR_IS_ALIGNED(host, getpagesize()));
+    assert(QEMU_IS_ALIGNED(size, getpagesize()));
+    trace_qemu_vfio_dma_map(s, host, size, temporary, iova);
+    qemu_mutex_lock(&s->lock);
+    mapping = qemu_vfio_find_mapping(s, host, &index);
+    if (mapping) {
+        iova0 = mapping->iova + ((uint8_t *)host - (uint8_t *)mapping->host);
+    } else {
+        if (s->high_water_mark - s->low_water_mark + 1 < size) {
+            ret = -ENOMEM;
+            goto out;
+        }
+        if (!temporary) {
+            iova0 = s->low_water_mark;
+            mapping = qemu_vfio_add_mapping(s, host, size, index + 1, iova0);
+            if (!mapping) {
+                ret = -ENOMEM;
+                goto out;
+            }
+            assert(qemu_vfio_verify_mappings(s));
+            ret = qemu_vfio_do_mapping(s, host, size, iova0);
+            if (ret) {
+                qemu_vfio_undo_mapping(s, mapping, NULL);
+                goto out;
+            }
+            s->low_water_mark += size;
+            qemu_vfio_dump_mappings(s);
+        } else {
+            iova0 = s->high_water_mark - size;
+            ret = qemu_vfio_do_mapping(s, host, size, iova0);
+            if (ret) {
+                goto out;
+            }
+            s->high_water_mark -= size;
+        }
+    }
+    if (iova) {
+        *iova = iova0;
+    }
+out:
+    qemu_mutex_unlock(&s->lock);
+    return ret;
+}
+
+/* Reset the high watermark and free all "temporary" mappings. */
+int qemu_vfio_dma_reset_temporary(QEMUVFIOState *s)
+{
+    struct vfio_iommu_type1_dma_unmap unmap = {
+        .argsz = sizeof(unmap),
+        .flags = 0,
+        .iova = s->high_water_mark,
+        .size = QEMU_VFIO_IOVA_MAX - s->high_water_mark,
+    };
+    trace_qemu_vfio_dma_reset_temporary(s);
+    qemu_mutex_lock(&s->lock);
+    if (ioctl(s->container, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
+        error_report("VFIO_UNMAP_DMA: %d", -errno);
+        qemu_mutex_unlock(&s->lock);
+        return -errno;
+    }
+    s->high_water_mark = QEMU_VFIO_IOVA_MAX;
+    qemu_mutex_unlock(&s->lock);
+    return 0;
+}
+
+/* Unmapping the whole area that was previously mapped with
+ * qemu_vfio_dma_map(). */
+void qemu_vfio_dma_unmap(QEMUVFIOState *s, void *host)
+{
+    int index = 0;
+    IOVAMapping *m;
+
+    if (!host) {
+        return;
+    }
+
+    trace_qemu_vfio_dma_unmap(s, host);
+    qemu_mutex_lock(&s->lock);
+    m = qemu_vfio_find_mapping(s, host, &index);
+    if (!m) {
+        goto out;
+    }
+    qemu_vfio_undo_mapping(s, m, NULL);
+out:
+    qemu_mutex_unlock(&s->lock);
+}
+
+static void qemu_vfio_reset(QEMUVFIOState *s)
+{
+    ioctl(s->device, VFIO_DEVICE_RESET);
+}
+
+/* Close and free the VFIO resources. */
+void qemu_vfio_close(QEMUVFIOState *s)
+{
+    int i;
+
+    if (!s) {
+        return;
+    }
+    for (i = 0; i < s->nr_mappings; ++i) {
+        qemu_vfio_undo_mapping(s, &s->mappings[i], NULL);
+    }
+    ram_block_notifier_remove(&s->ram_notifier);
+    qemu_vfio_reset(s);
+    close(s->device);
+    close(s->group);
+    close(s->container);
+}