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-rw-r--r--block/blkio.c831
1 files changed, 831 insertions, 0 deletions
diff --git a/block/blkio.c b/block/blkio.c
new file mode 100644
index 0000000..b0cfd74
--- /dev/null
+++ b/block/blkio.c
@@ -0,0 +1,831 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * libblkio BlockDriver
+ *
+ * Copyright Red Hat, Inc.
+ *
+ * Author:
+ * Stefan Hajnoczi <stefanha@redhat.com>
+ */
+
+#include "qemu/osdep.h"
+#include <blkio.h>
+#include "block/block_int.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qemu/module.h"
+
+/*
+ * Keep the QEMU BlockDriver names identical to the libblkio driver names.
+ * Using macros instead of typing out the string literals avoids typos.
+ */
+#define DRIVER_IO_URING "io_uring"
+#define DRIVER_NVME_IO_URING "nvme-io_uring"
+#define DRIVER_VIRTIO_BLK_VHOST_USER "virtio-blk-vhost-user"
+#define DRIVER_VIRTIO_BLK_VHOST_VDPA "virtio-blk-vhost-vdpa"
+
+/*
+ * Allocated bounce buffers are kept in a list sorted by buffer address.
+ */
+typedef struct BlkioBounceBuf {
+ QLIST_ENTRY(BlkioBounceBuf) next;
+
+ /* The bounce buffer */
+ struct iovec buf;
+} BlkioBounceBuf;
+
+typedef struct {
+ /*
+ * libblkio is not thread-safe so this lock protects ->blkio and
+ * ->blkioq.
+ */
+ QemuMutex blkio_lock;
+ struct blkio *blkio;
+ struct blkioq *blkioq; /* make this multi-queue in the future... */
+ int completion_fd;
+
+ /*
+ * Polling fetches the next completion into this field.
+ *
+ * No lock is necessary since only one thread calls aio_poll() and invokes
+ * fd and poll handlers.
+ */
+ struct blkio_completion poll_completion;
+
+ /*
+ * Protects ->bounce_pool, ->bounce_bufs, ->bounce_available.
+ *
+ * Lock ordering: ->bounce_lock before ->blkio_lock.
+ */
+ CoMutex bounce_lock;
+
+ /* Bounce buffer pool */
+ struct blkio_mem_region bounce_pool;
+
+ /* Sorted list of allocated bounce buffers */
+ QLIST_HEAD(, BlkioBounceBuf) bounce_bufs;
+
+ /* Queue for coroutines waiting for bounce buffer space */
+ CoQueue bounce_available;
+
+ /* The value of the "mem-region-alignment" property */
+ size_t mem_region_alignment;
+
+ /* Can we skip adding/deleting blkio_mem_regions? */
+ bool needs_mem_regions;
+} BDRVBlkioState;
+
+/* Called with s->bounce_lock held */
+static int blkio_resize_bounce_pool(BDRVBlkioState *s, int64_t bytes)
+{
+ /* There can be no allocated bounce buffers during resize */
+ assert(QLIST_EMPTY(&s->bounce_bufs));
+
+ /* Pad size to reduce frequency of resize calls */
+ bytes += 128 * 1024;
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ int ret;
+
+ if (s->bounce_pool.addr) {
+ blkio_unmap_mem_region(s->blkio, &s->bounce_pool);
+ blkio_free_mem_region(s->blkio, &s->bounce_pool);
+ memset(&s->bounce_pool, 0, sizeof(s->bounce_pool));
+ }
+
+ /* Automatically freed when s->blkio is destroyed */
+ ret = blkio_alloc_mem_region(s->blkio, &s->bounce_pool, bytes);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = blkio_map_mem_region(s->blkio, &s->bounce_pool);
+ if (ret < 0) {
+ blkio_free_mem_region(s->blkio, &s->bounce_pool);
+ memset(&s->bounce_pool, 0, sizeof(s->bounce_pool));
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/* Called with s->bounce_lock held */
+static bool
+blkio_do_alloc_bounce_buffer(BDRVBlkioState *s, BlkioBounceBuf *bounce,
+ int64_t bytes)
+{
+ void *addr = s->bounce_pool.addr;
+ BlkioBounceBuf *cur = NULL;
+ BlkioBounceBuf *prev = NULL;
+ ptrdiff_t space;
+
+ /*
+ * This is just a linear search over the holes between requests. An
+ * efficient allocator would be nice.
+ */
+ QLIST_FOREACH(cur, &s->bounce_bufs, next) {
+ space = cur->buf.iov_base - addr;
+ if (bytes <= space) {
+ QLIST_INSERT_BEFORE(cur, bounce, next);
+ bounce->buf.iov_base = addr;
+ bounce->buf.iov_len = bytes;
+ return true;
+ }
+
+ addr = cur->buf.iov_base + cur->buf.iov_len;
+ prev = cur;
+ }
+
+ /* Is there space after the last request? */
+ space = s->bounce_pool.addr + s->bounce_pool.len - addr;
+ if (bytes > space) {
+ return false;
+ }
+ if (prev) {
+ QLIST_INSERT_AFTER(prev, bounce, next);
+ } else {
+ QLIST_INSERT_HEAD(&s->bounce_bufs, bounce, next);
+ }
+ bounce->buf.iov_base = addr;
+ bounce->buf.iov_len = bytes;
+ return true;
+}
+
+static int coroutine_fn
+blkio_alloc_bounce_buffer(BDRVBlkioState *s, BlkioBounceBuf *bounce,
+ int64_t bytes)
+{
+ /*
+ * Ensure fairness: first time around we join the back of the queue,
+ * subsequently we join the front so we don't lose our place.
+ */
+ CoQueueWaitFlags wait_flags = 0;
+
+ QEMU_LOCK_GUARD(&s->bounce_lock);
+
+ /* Ensure fairness: don't even try if other requests are already waiting */
+ if (!qemu_co_queue_empty(&s->bounce_available)) {
+ qemu_co_queue_wait_flags(&s->bounce_available, &s->bounce_lock,
+ wait_flags);
+ wait_flags = CO_QUEUE_WAIT_FRONT;
+ }
+
+ while (true) {
+ if (blkio_do_alloc_bounce_buffer(s, bounce, bytes)) {
+ /* Kick the next queued request since there may be space */
+ qemu_co_queue_next(&s->bounce_available);
+ return 0;
+ }
+
+ /*
+ * If there are no in-flight requests then the pool was simply too
+ * small.
+ */
+ if (QLIST_EMPTY(&s->bounce_bufs)) {
+ bool ok;
+ int ret;
+
+ ret = blkio_resize_bounce_pool(s, bytes);
+ if (ret < 0) {
+ /* Kick the next queued request since that may fail too */
+ qemu_co_queue_next(&s->bounce_available);
+ return ret;
+ }
+
+ ok = blkio_do_alloc_bounce_buffer(s, bounce, bytes);
+ assert(ok); /* must have space this time */
+ return 0;
+ }
+
+ qemu_co_queue_wait_flags(&s->bounce_available, &s->bounce_lock,
+ wait_flags);
+ wait_flags = CO_QUEUE_WAIT_FRONT;
+ }
+}
+
+static void coroutine_fn blkio_free_bounce_buffer(BDRVBlkioState *s,
+ BlkioBounceBuf *bounce)
+{
+ QEMU_LOCK_GUARD(&s->bounce_lock);
+
+ QLIST_REMOVE(bounce, next);
+
+ /* Wake up waiting coroutines since space may now be available */
+ qemu_co_queue_next(&s->bounce_available);
+}
+
+/* For async to .bdrv_co_*() conversion */
+typedef struct {
+ Coroutine *coroutine;
+ int ret;
+} BlkioCoData;
+
+static void blkio_completion_fd_read(void *opaque)
+{
+ BlockDriverState *bs = opaque;
+ BDRVBlkioState *s = bs->opaque;
+ uint64_t val;
+ int ret;
+
+ /* Polling may have already fetched a completion */
+ if (s->poll_completion.user_data != NULL) {
+ BlkioCoData *cod = s->poll_completion.user_data;
+ cod->ret = s->poll_completion.ret;
+
+ /* Clear it in case aio_co_wake() enters a nested event loop */
+ s->poll_completion.user_data = NULL;
+
+ aio_co_wake(cod->coroutine);
+ }
+
+ /* Reset completion fd status */
+ ret = read(s->completion_fd, &val, sizeof(val));
+
+ /* Ignore errors, there's nothing we can do */
+ (void)ret;
+
+ /*
+ * Reading one completion at a time makes nested event loop re-entrancy
+ * simple. Change this loop to get multiple completions in one go if it
+ * becomes a performance bottleneck.
+ */
+ while (true) {
+ struct blkio_completion completion;
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ ret = blkioq_do_io(s->blkioq, &completion, 0, 1, NULL);
+ }
+ if (ret != 1) {
+ break;
+ }
+
+ BlkioCoData *cod = completion.user_data;
+ cod->ret = completion.ret;
+ aio_co_wake(cod->coroutine);
+ }
+}
+
+static bool blkio_completion_fd_poll(void *opaque)
+{
+ BlockDriverState *bs = opaque;
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ /* Just in case we already fetched a completion */
+ if (s->poll_completion.user_data != NULL) {
+ return true;
+ }
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ ret = blkioq_do_io(s->blkioq, &s->poll_completion, 0, 1, NULL);
+ }
+ return ret == 1;
+}
+
+static void blkio_completion_fd_poll_ready(void *opaque)
+{
+ blkio_completion_fd_read(opaque);
+}
+
+static void blkio_attach_aio_context(BlockDriverState *bs,
+ AioContext *new_context)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ aio_set_fd_handler(new_context,
+ s->completion_fd,
+ false,
+ blkio_completion_fd_read,
+ NULL,
+ blkio_completion_fd_poll,
+ blkio_completion_fd_poll_ready,
+ bs);
+}
+
+static void blkio_detach_aio_context(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ aio_set_fd_handler(bdrv_get_aio_context(bs),
+ s->completion_fd,
+ false, NULL, NULL, NULL, NULL, NULL);
+}
+
+/* Call with s->blkio_lock held to submit I/O after enqueuing a new request */
+static void blkio_submit_io(BlockDriverState *bs)
+{
+ if (qatomic_read(&bs->io_plugged) == 0) {
+ BDRVBlkioState *s = bs->opaque;
+
+ blkioq_do_io(s->blkioq, NULL, 0, 0, NULL);
+ }
+}
+
+static int coroutine_fn
+blkio_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
+{
+ BDRVBlkioState *s = bs->opaque;
+ BlkioCoData cod = {
+ .coroutine = qemu_coroutine_self(),
+ };
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ blkioq_discard(s->blkioq, offset, bytes, &cod, 0);
+ blkio_submit_io(bs);
+ }
+
+ qemu_coroutine_yield();
+ return cod.ret;
+}
+
+static int coroutine_fn
+blkio_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+ QEMUIOVector *qiov, BdrvRequestFlags flags)
+{
+ BlkioCoData cod = {
+ .coroutine = qemu_coroutine_self(),
+ };
+ BDRVBlkioState *s = bs->opaque;
+ bool use_bounce_buffer = s->needs_mem_regions;
+ BlkioBounceBuf bounce;
+ struct iovec *iov = qiov->iov;
+ int iovcnt = qiov->niov;
+
+ if (use_bounce_buffer) {
+ int ret = blkio_alloc_bounce_buffer(s, &bounce, bytes);
+ if (ret < 0) {
+ return ret;
+ }
+
+ iov = &bounce.buf;
+ iovcnt = 1;
+ }
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ blkioq_readv(s->blkioq, offset, iov, iovcnt, &cod, 0);
+ blkio_submit_io(bs);
+ }
+
+ qemu_coroutine_yield();
+
+ if (use_bounce_buffer) {
+ if (cod.ret == 0) {
+ qemu_iovec_from_buf(qiov, 0,
+ bounce.buf.iov_base,
+ bounce.buf.iov_len);
+ }
+
+ blkio_free_bounce_buffer(s, &bounce);
+ }
+
+ return cod.ret;
+}
+
+static int coroutine_fn blkio_co_pwritev(BlockDriverState *bs, int64_t offset,
+ int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags)
+{
+ uint32_t blkio_flags = (flags & BDRV_REQ_FUA) ? BLKIO_REQ_FUA : 0;
+ BlkioCoData cod = {
+ .coroutine = qemu_coroutine_self(),
+ };
+ BDRVBlkioState *s = bs->opaque;
+ bool use_bounce_buffer = s->needs_mem_regions;
+ BlkioBounceBuf bounce;
+ struct iovec *iov = qiov->iov;
+ int iovcnt = qiov->niov;
+
+ if (use_bounce_buffer) {
+ int ret = blkio_alloc_bounce_buffer(s, &bounce, bytes);
+ if (ret < 0) {
+ return ret;
+ }
+
+ qemu_iovec_to_buf(qiov, 0, bounce.buf.iov_base, bytes);
+ iov = &bounce.buf;
+ iovcnt = 1;
+ }
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ blkioq_writev(s->blkioq, offset, iov, iovcnt, &cod, blkio_flags);
+ blkio_submit_io(bs);
+ }
+
+ qemu_coroutine_yield();
+
+ if (use_bounce_buffer) {
+ blkio_free_bounce_buffer(s, &bounce);
+ }
+
+ return cod.ret;
+}
+
+static int coroutine_fn blkio_co_flush(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+ BlkioCoData cod = {
+ .coroutine = qemu_coroutine_self(),
+ };
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ blkioq_flush(s->blkioq, &cod, 0);
+ blkio_submit_io(bs);
+ }
+
+ qemu_coroutine_yield();
+ return cod.ret;
+}
+
+static int coroutine_fn blkio_co_pwrite_zeroes(BlockDriverState *bs,
+ int64_t offset, int64_t bytes, BdrvRequestFlags flags)
+{
+ BDRVBlkioState *s = bs->opaque;
+ BlkioCoData cod = {
+ .coroutine = qemu_coroutine_self(),
+ };
+ uint32_t blkio_flags = 0;
+
+ if (flags & BDRV_REQ_FUA) {
+ blkio_flags |= BLKIO_REQ_FUA;
+ }
+ if (!(flags & BDRV_REQ_MAY_UNMAP)) {
+ blkio_flags |= BLKIO_REQ_NO_UNMAP;
+ }
+ if (flags & BDRV_REQ_NO_FALLBACK) {
+ blkio_flags |= BLKIO_REQ_NO_FALLBACK;
+ }
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ blkioq_write_zeroes(s->blkioq, offset, bytes, &cod, blkio_flags);
+ blkio_submit_io(bs);
+ }
+
+ qemu_coroutine_yield();
+ return cod.ret;
+}
+
+static void blkio_io_unplug(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ blkio_submit_io(bs);
+ }
+}
+
+static int blkio_io_uring_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ const char *filename = qdict_get_str(options, "filename");
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ ret = blkio_set_str(s->blkio, "path", filename);
+ qdict_del(options, "filename");
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set path: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (flags & BDRV_O_NOCACHE) {
+ ret = blkio_set_bool(s->blkio, "direct", true);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set direct: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int blkio_nvme_io_uring(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ const char *filename = qdict_get_str(options, "filename");
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ ret = blkio_set_str(s->blkio, "path", filename);
+ qdict_del(options, "filename");
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set path: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (!(flags & BDRV_O_NOCACHE)) {
+ error_setg(errp, "cache.direct=off is not supported");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int blkio_virtio_blk_common_open(BlockDriverState *bs,
+ QDict *options, int flags, Error **errp)
+{
+ const char *path = qdict_get_try_str(options, "path");
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ if (!path) {
+ error_setg(errp, "missing 'path' option");
+ return -EINVAL;
+ }
+
+ ret = blkio_set_str(s->blkio, "path", path);
+ qdict_del(options, "path");
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set path: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (!(flags & BDRV_O_NOCACHE)) {
+ error_setg(errp, "cache.direct=off is not supported");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int blkio_file_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ const char *blkio_driver = bs->drv->protocol_name;
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ ret = blkio_create(blkio_driver, &s->blkio);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "blkio_create failed: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (strcmp(blkio_driver, DRIVER_IO_URING) == 0) {
+ ret = blkio_io_uring_open(bs, options, flags, errp);
+ } else if (strcmp(blkio_driver, DRIVER_NVME_IO_URING) == 0) {
+ ret = blkio_nvme_io_uring(bs, options, flags, errp);
+ } else if (strcmp(blkio_driver, DRIVER_VIRTIO_BLK_VHOST_USER) == 0) {
+ ret = blkio_virtio_blk_common_open(bs, options, flags, errp);
+ } else if (strcmp(blkio_driver, DRIVER_VIRTIO_BLK_VHOST_VDPA) == 0) {
+ ret = blkio_virtio_blk_common_open(bs, options, flags, errp);
+ } else {
+ g_assert_not_reached();
+ }
+ if (ret < 0) {
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ if (!(flags & BDRV_O_RDWR)) {
+ ret = blkio_set_bool(s->blkio, "read-only", true);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set read-only: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+ }
+
+ ret = blkio_connect(s->blkio);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "blkio_connect failed: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ ret = blkio_get_bool(s->blkio,
+ "needs-mem-regions",
+ &s->needs_mem_regions);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "failed to get needs-mem-regions: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ ret = blkio_get_uint64(s->blkio,
+ "mem-region-alignment",
+ &s->mem_region_alignment);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "failed to get mem-region-alignment: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ ret = blkio_start(s->blkio);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "blkio_start failed: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ bs->supported_write_flags = BDRV_REQ_FUA;
+ bs->supported_zero_flags = BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP |
+ BDRV_REQ_NO_FALLBACK;
+
+ qemu_mutex_init(&s->blkio_lock);
+ qemu_co_mutex_init(&s->bounce_lock);
+ qemu_co_queue_init(&s->bounce_available);
+ QLIST_INIT(&s->bounce_bufs);
+ s->blkioq = blkio_get_queue(s->blkio, 0);
+ s->completion_fd = blkioq_get_completion_fd(s->blkioq);
+
+ blkio_attach_aio_context(bs, bdrv_get_aio_context(bs));
+ return 0;
+}
+
+static void blkio_close(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ /* There is no destroy() API for s->bounce_lock */
+
+ qemu_mutex_destroy(&s->blkio_lock);
+ blkio_detach_aio_context(bs);
+ blkio_destroy(&s->blkio);
+}
+
+static int64_t blkio_getlength(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+ uint64_t capacity;
+ int ret;
+
+ WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
+ ret = blkio_get_uint64(s->blkio, "capacity", &capacity);
+ }
+ if (ret < 0) {
+ return -ret;
+ }
+
+ return capacity;
+}
+
+static int blkio_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ return 0;
+}
+
+static void blkio_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+ BDRVBlkioState *s = bs->opaque;
+ QEMU_LOCK_GUARD(&s->blkio_lock);
+ int value;
+ int ret;
+
+ ret = blkio_get_int(s->blkio, "request-alignment", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"request-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ bs->bl.request_alignment = value;
+ if (bs->bl.request_alignment < 1 ||
+ bs->bl.request_alignment >= INT_MAX ||
+ !is_power_of_2(bs->bl.request_alignment)) {
+ error_setg(errp, "invalid \"request-alignment\" value %" PRIu32 ", "
+ "must be a power of 2 less than INT_MAX",
+ bs->bl.request_alignment);
+ return;
+ }
+
+ ret = blkio_get_int(s->blkio, "optimal-io-size", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"optimal-io-size\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ bs->bl.opt_transfer = value;
+ if (bs->bl.opt_transfer > INT_MAX ||
+ (bs->bl.opt_transfer % bs->bl.request_alignment)) {
+ error_setg(errp, "invalid \"optimal-io-size\" value %" PRIu32 ", must "
+ "be a multiple of %" PRIu32, bs->bl.opt_transfer,
+ bs->bl.request_alignment);
+ return;
+ }
+
+ ret = blkio_get_int(s->blkio, "max-transfer", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"max-transfer\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ bs->bl.max_transfer = value;
+ if ((bs->bl.max_transfer % bs->bl.request_alignment) ||
+ (bs->bl.opt_transfer && (bs->bl.max_transfer % bs->bl.opt_transfer))) {
+ error_setg(errp, "invalid \"max-transfer\" value %" PRIu32 ", must be "
+ "a multiple of %" PRIu32 " and %" PRIu32 " (if non-zero)",
+ bs->bl.max_transfer, bs->bl.request_alignment,
+ bs->bl.opt_transfer);
+ return;
+ }
+
+ ret = blkio_get_int(s->blkio, "buf-alignment", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"buf-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (value < 1) {
+ error_setg(errp, "invalid \"buf-alignment\" value %d, must be "
+ "positive", value);
+ return;
+ }
+ bs->bl.min_mem_alignment = value;
+
+ ret = blkio_get_int(s->blkio, "optimal-buf-alignment", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "failed to get \"optimal-buf-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (value < 1) {
+ error_setg(errp, "invalid \"optimal-buf-alignment\" value %d, "
+ "must be positive", value);
+ return;
+ }
+ bs->bl.opt_mem_alignment = value;
+
+ ret = blkio_get_int(s->blkio, "max-segments", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"max-segments\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (value < 1) {
+ error_setg(errp, "invalid \"max-segments\" value %d, must be positive",
+ value);
+ return;
+ }
+ bs->bl.max_iov = value;
+}
+
+/*
+ * TODO
+ * Missing libblkio APIs:
+ * - block_status
+ * - co_invalidate_cache
+ *
+ * Out of scope?
+ * - create
+ * - truncate
+ */
+
+#define BLKIO_DRIVER(name, ...) \
+ { \
+ .format_name = name, \
+ .protocol_name = name, \
+ .instance_size = sizeof(BDRVBlkioState), \
+ .bdrv_file_open = blkio_file_open, \
+ .bdrv_close = blkio_close, \
+ .bdrv_getlength = blkio_getlength, \
+ .bdrv_get_info = blkio_get_info, \
+ .bdrv_attach_aio_context = blkio_attach_aio_context, \
+ .bdrv_detach_aio_context = blkio_detach_aio_context, \
+ .bdrv_co_pdiscard = blkio_co_pdiscard, \
+ .bdrv_co_preadv = blkio_co_preadv, \
+ .bdrv_co_pwritev = blkio_co_pwritev, \
+ .bdrv_co_flush_to_disk = blkio_co_flush, \
+ .bdrv_co_pwrite_zeroes = blkio_co_pwrite_zeroes, \
+ .bdrv_io_unplug = blkio_io_unplug, \
+ .bdrv_refresh_limits = blkio_refresh_limits, \
+ __VA_ARGS__ \
+ }
+
+static BlockDriver bdrv_io_uring = BLKIO_DRIVER(
+ DRIVER_IO_URING,
+ .bdrv_needs_filename = true,
+);
+
+static BlockDriver bdrv_nvme_io_uring = BLKIO_DRIVER(
+ DRIVER_NVME_IO_URING,
+ .bdrv_needs_filename = true,
+);
+
+static BlockDriver bdrv_virtio_blk_vhost_user = BLKIO_DRIVER(
+ DRIVER_VIRTIO_BLK_VHOST_USER
+);
+
+static BlockDriver bdrv_virtio_blk_vhost_vdpa = BLKIO_DRIVER(
+ DRIVER_VIRTIO_BLK_VHOST_VDPA
+);
+
+static void bdrv_blkio_init(void)
+{
+ bdrv_register(&bdrv_io_uring);
+ bdrv_register(&bdrv_nvme_io_uring);
+ bdrv_register(&bdrv_virtio_blk_vhost_user);
+ bdrv_register(&bdrv_virtio_blk_vhost_vdpa);
+}
+
+block_init(bdrv_blkio_init);