hw/i386/xen/: move xen-mapcache.c to hw/xen/

xen-mapcache.c contains common functions which can be used for enabling Xen on
aarch64 with IOREQ handling. Moving it out from hw/i386/xen to hw/xen to make it
accessible for both aarch64 and x86.

Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Reviewed-by: Paul Durrant <paul@xen.org>

3 files changed, 608 insertions, 0 deletions

diff --git a/hw/xen/meson.build b/hw/xen/meson.build
index 19c6aab..202752e 100644
--- a/hw/xen/meson.build
+++ b/hw/xen/meson.build
@@ -26,3 +26,7 @@ else
 endif
 
 specific_ss.add_all(when: ['CONFIG_XEN', xen], if_true: xen_specific_ss)
+
+xen_ss = ss.source_set()
+
+xen_ss.add(when: 'CONFIG_XEN', if_true: files('xen-mapcache.c'))
diff --git a/hw/xen/trace-events b/hw/xen/trace-events
index 55c9e1d..f977c7c 100644
--- a/hw/xen/trace-events
+++ b/hw/xen/trace-events
@@ -41,3 +41,8 @@ xs_node_vprintf(char *path, char *value) "%s %s"
 xs_node_vscanf(char *path, char *value) "%s %s"
 xs_node_watch(char *path) "%s"
 xs_node_unwatch(char *path) "%s"
+
+# xen-mapcache.c
+xen_map_cache(uint64_t phys_addr) "want 0x%"PRIx64
+xen_remap_bucket(uint64_t index) "index 0x%"PRIx64
+xen_map_cache_return(void* ptr) "%p"
diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c
new file mode 100644
index 0000000..f7d9746
--- /dev/null
+++ b/hw/xen/xen-mapcache.c
@@ -0,0 +1,599 @@
+/*
+ * Copyright (C) 2011       Citrix Ltd.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include "qemu/error-report.h"
+
+#include <sys/resource.h>
+
+#include "hw/xen/xen_native.h"
+#include "qemu/bitmap.h"
+
+#include "sysemu/runstate.h"
+#include "sysemu/xen-mapcache.h"
+#include "trace.h"
+
+
+//#define MAPCACHE_DEBUG
+
+#ifdef MAPCACHE_DEBUG
+#  define DPRINTF(fmt, ...) do { \
+    fprintf(stderr, "xen_mapcache: " fmt, ## __VA_ARGS__); \
+} while (0)
+#else
+#  define DPRINTF(fmt, ...) do { } while (0)
+#endif
+
+#if HOST_LONG_BITS == 32
+#  define MCACHE_BUCKET_SHIFT 16
+#  define MCACHE_MAX_SIZE     (1UL<<31) /* 2GB Cap */
+#else
+#  define MCACHE_BUCKET_SHIFT 20
+#  define MCACHE_MAX_SIZE     (1UL<<35) /* 32GB Cap */
+#endif
+#define MCACHE_BUCKET_SIZE (1UL << MCACHE_BUCKET_SHIFT)
+
+/* This is the size of the virtual address space reserve to QEMU that will not
+ * be use by MapCache.
+ * From empirical tests I observed that qemu use 75MB more than the
+ * max_mcache_size.
+ */
+#define NON_MCACHE_MEMORY_SIZE (80 * MiB)
+
+typedef struct MapCacheEntry {
+    hwaddr paddr_index;
+    uint8_t *vaddr_base;
+    unsigned long *valid_mapping;
+    uint32_t lock;
+#define XEN_MAPCACHE_ENTRY_DUMMY (1 << 0)
+    uint8_t flags;
+    hwaddr size;
+    struct MapCacheEntry *next;
+} MapCacheEntry;
+
+typedef struct MapCacheRev {
+    uint8_t *vaddr_req;
+    hwaddr paddr_index;
+    hwaddr size;
+    QTAILQ_ENTRY(MapCacheRev) next;
+    bool dma;
+} MapCacheRev;
+
+typedef struct MapCache {
+    MapCacheEntry *entry;
+    unsigned long nr_buckets;
+    QTAILQ_HEAD(, MapCacheRev) locked_entries;
+
+    /* For most cases (>99.9%), the page address is the same. */
+    MapCacheEntry *last_entry;
+    unsigned long max_mcache_size;
+    unsigned int mcache_bucket_shift;
+
+    phys_offset_to_gaddr_t phys_offset_to_gaddr;
+    QemuMutex lock;
+    void *opaque;
+} MapCache;
+
+static MapCache *mapcache;
+
+static inline void mapcache_lock(void)
+{
+    qemu_mutex_lock(&mapcache->lock);
+}
+
+static inline void mapcache_unlock(void)
+{
+    qemu_mutex_unlock(&mapcache->lock);
+}
+
+static inline int test_bits(int nr, int size, const unsigned long *addr)
+{
+    unsigned long res = find_next_zero_bit(addr, size + nr, nr);
+    if (res >= nr + size)
+        return 1;
+    else
+        return 0;
+}
+
+void xen_map_cache_init(phys_offset_to_gaddr_t f, void *opaque)
+{
+    unsigned long size;
+    struct rlimit rlimit_as;
+
+    mapcache = g_new0(MapCache, 1);
+
+    mapcache->phys_offset_to_gaddr = f;
+    mapcache->opaque = opaque;
+    qemu_mutex_init(&mapcache->lock);
+
+    QTAILQ_INIT(&mapcache->locked_entries);
+
+    if (geteuid() == 0) {
+        rlimit_as.rlim_cur = RLIM_INFINITY;
+        rlimit_as.rlim_max = RLIM_INFINITY;
+        mapcache->max_mcache_size = MCACHE_MAX_SIZE;
+    } else {
+        getrlimit(RLIMIT_AS, &rlimit_as);
+        rlimit_as.rlim_cur = rlimit_as.rlim_max;
+
+        if (rlimit_as.rlim_max != RLIM_INFINITY) {
+            warn_report("QEMU's maximum size of virtual"
+                        " memory is not infinity");
+        }
+        if (rlimit_as.rlim_max < MCACHE_MAX_SIZE + NON_MCACHE_MEMORY_SIZE) {
+            mapcache->max_mcache_size = rlimit_as.rlim_max -
+                NON_MCACHE_MEMORY_SIZE;
+        } else {
+            mapcache->max_mcache_size = MCACHE_MAX_SIZE;
+        }
+    }
+
+    setrlimit(RLIMIT_AS, &rlimit_as);
+
+    mapcache->nr_buckets =
+        (((mapcache->max_mcache_size >> XC_PAGE_SHIFT) +
+          (1UL << (MCACHE_BUCKET_SHIFT - XC_PAGE_SHIFT)) - 1) >>
+         (MCACHE_BUCKET_SHIFT - XC_PAGE_SHIFT));
+
+    size = mapcache->nr_buckets * sizeof (MapCacheEntry);
+    size = (size + XC_PAGE_SIZE - 1) & ~(XC_PAGE_SIZE - 1);
+    DPRINTF("%s, nr_buckets = %lx size %lu\n", __func__,
+            mapcache->nr_buckets, size);
+    mapcache->entry = g_malloc0(size);
+}
+
+static void xen_remap_bucket(MapCacheEntry *entry,
+                             void *vaddr,
+                             hwaddr size,
+                             hwaddr address_index,
+                             bool dummy)
+{
+    uint8_t *vaddr_base;
+    xen_pfn_t *pfns;
+    int *err;
+    unsigned int i;
+    hwaddr nb_pfn = size >> XC_PAGE_SHIFT;
+
+    trace_xen_remap_bucket(address_index);
+
+    pfns = g_new0(xen_pfn_t, nb_pfn);
+    err = g_new0(int, nb_pfn);
+
+    if (entry->vaddr_base != NULL) {
+        if (!(entry->flags & XEN_MAPCACHE_ENTRY_DUMMY)) {
+            ram_block_notify_remove(entry->vaddr_base, entry->size,
+                                    entry->size);
+        }
+
+        /*
+         * If an entry is being replaced by another mapping and we're using
+         * MAP_FIXED flag for it - there is possibility of a race for vaddr
+         * address with another thread doing an mmap call itself
+         * (see man 2 mmap). To avoid that we skip explicit unmapping here
+         * and allow the kernel to destroy the previous mappings by replacing
+         * them in mmap call later.
+         *
+         * Non-identical replacements are not allowed therefore.
+         */
+        assert(!vaddr || (entry->vaddr_base == vaddr && entry->size == size));
+
+        if (!vaddr && munmap(entry->vaddr_base, entry->size) != 0) {
+            perror("unmap fails");
+            exit(-1);
+        }
+    }
+    g_free(entry->valid_mapping);
+    entry->valid_mapping = NULL;
+
+    for (i = 0; i < nb_pfn; i++) {
+        pfns[i] = (address_index << (MCACHE_BUCKET_SHIFT-XC_PAGE_SHIFT)) + i;
+    }
+
+    /*
+     * If the caller has requested the mapping at a specific address use
+     * MAP_FIXED to make sure it's honored.
+     */
+    if (!dummy) {
+        vaddr_base = xenforeignmemory_map2(xen_fmem, xen_domid, vaddr,
+                                           PROT_READ | PROT_WRITE,
+                                           vaddr ? MAP_FIXED : 0,
+                                           nb_pfn, pfns, err);
+        if (vaddr_base == NULL) {
+            perror("xenforeignmemory_map2");
+            exit(-1);
+        }
+    } else {
+        /*
+         * We create dummy mappings where we are unable to create a foreign
+         * mapping immediately due to certain circumstances (i.e. on resume now)
+         */
+        vaddr_base = mmap(vaddr, size, PROT_READ | PROT_WRITE,
+                          MAP_ANON | MAP_SHARED | (vaddr ? MAP_FIXED : 0),
+                          -1, 0);
+        if (vaddr_base == MAP_FAILED) {
+            perror("mmap");
+            exit(-1);
+        }
+    }
+
+    if (!(entry->flags & XEN_MAPCACHE_ENTRY_DUMMY)) {
+        ram_block_notify_add(vaddr_base, size, size);
+    }
+
+    entry->vaddr_base = vaddr_base;
+    entry->paddr_index = address_index;
+    entry->size = size;
+    entry->valid_mapping = g_new0(unsigned long,
+                                  BITS_TO_LONGS(size >> XC_PAGE_SHIFT));
+
+    if (dummy) {
+        entry->flags |= XEN_MAPCACHE_ENTRY_DUMMY;
+    } else {
+        entry->flags &= ~(XEN_MAPCACHE_ENTRY_DUMMY);
+    }
+
+    bitmap_zero(entry->valid_mapping, nb_pfn);
+    for (i = 0; i < nb_pfn; i++) {
+        if (!err[i]) {
+            bitmap_set(entry->valid_mapping, i, 1);
+        }
+    }
+
+    g_free(pfns);
+    g_free(err);
+}
+
+static uint8_t *xen_map_cache_unlocked(hwaddr phys_addr, hwaddr size,
+                                       uint8_t lock, bool dma)
+{
+    MapCacheEntry *entry, *pentry = NULL,
+                  *free_entry = NULL, *free_pentry = NULL;
+    hwaddr address_index;
+    hwaddr address_offset;
+    hwaddr cache_size = size;
+    hwaddr test_bit_size;
+    bool translated G_GNUC_UNUSED = false;
+    bool dummy = false;
+
+tryagain:
+    address_index  = phys_addr >> MCACHE_BUCKET_SHIFT;
+    address_offset = phys_addr & (MCACHE_BUCKET_SIZE - 1);
+
+    trace_xen_map_cache(phys_addr);
+
+    /* test_bit_size is always a multiple of XC_PAGE_SIZE */
+    if (size) {
+        test_bit_size = size + (phys_addr & (XC_PAGE_SIZE - 1));
+
+        if (test_bit_size % XC_PAGE_SIZE) {
+            test_bit_size += XC_PAGE_SIZE - (test_bit_size % XC_PAGE_SIZE);
+        }
+    } else {
+        test_bit_size = XC_PAGE_SIZE;
+    }
+
+    if (mapcache->last_entry != NULL &&
+        mapcache->last_entry->paddr_index == address_index &&
+        !lock && !size &&
+        test_bits(address_offset >> XC_PAGE_SHIFT,
+                  test_bit_size >> XC_PAGE_SHIFT,
+                  mapcache->last_entry->valid_mapping)) {
+        trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset);
+        return mapcache->last_entry->vaddr_base + address_offset;
+    }
+
+    /* size is always a multiple of MCACHE_BUCKET_SIZE */
+    if (size) {
+        cache_size = size + address_offset;
+        if (cache_size % MCACHE_BUCKET_SIZE) {
+            cache_size += MCACHE_BUCKET_SIZE - (cache_size % MCACHE_BUCKET_SIZE);
+        }
+    } else {
+        cache_size = MCACHE_BUCKET_SIZE;
+    }
+
+    entry = &mapcache->entry[address_index % mapcache->nr_buckets];
+
+    while (entry && (lock || entry->lock) && entry->vaddr_base &&
+            (entry->paddr_index != address_index || entry->size != cache_size ||
+             !test_bits(address_offset >> XC_PAGE_SHIFT,
+                 test_bit_size >> XC_PAGE_SHIFT,
+                 entry->valid_mapping))) {
+        if (!free_entry && !entry->lock) {
+            free_entry = entry;
+            free_pentry = pentry;
+        }
+        pentry = entry;
+        entry = entry->next;
+    }
+    if (!entry && free_entry) {
+        entry = free_entry;
+        pentry = free_pentry;
+    }
+    if (!entry) {
+        entry = g_new0(MapCacheEntry, 1);
+        pentry->next = entry;
+        xen_remap_bucket(entry, NULL, cache_size, address_index, dummy);
+    } else if (!entry->lock) {
+        if (!entry->vaddr_base || entry->paddr_index != address_index ||
+                entry->size != cache_size ||
+                !test_bits(address_offset >> XC_PAGE_SHIFT,
+                    test_bit_size >> XC_PAGE_SHIFT,
+                    entry->valid_mapping)) {
+            xen_remap_bucket(entry, NULL, cache_size, address_index, dummy);
+        }
+    }
+
+    if(!test_bits(address_offset >> XC_PAGE_SHIFT,
+                test_bit_size >> XC_PAGE_SHIFT,
+                entry->valid_mapping)) {
+        mapcache->last_entry = NULL;
+#ifdef XEN_COMPAT_PHYSMAP
+        if (!translated && mapcache->phys_offset_to_gaddr) {
+            phys_addr = mapcache->phys_offset_to_gaddr(phys_addr, size);
+            translated = true;
+            goto tryagain;
+        }
+#endif
+        if (!dummy && runstate_check(RUN_STATE_INMIGRATE)) {
+            dummy = true;
+            goto tryagain;
+        }
+        trace_xen_map_cache_return(NULL);
+        return NULL;
+    }
+
+    mapcache->last_entry = entry;
+    if (lock) {
+        MapCacheRev *reventry = g_new0(MapCacheRev, 1);
+        entry->lock++;
+        if (entry->lock == 0) {
+            fprintf(stderr,
+                    "mapcache entry lock overflow: "HWADDR_FMT_plx" -> %p\n",
+                    entry->paddr_index, entry->vaddr_base);
+            abort();
+        }
+        reventry->dma = dma;
+        reventry->vaddr_req = mapcache->last_entry->vaddr_base + address_offset;
+        reventry->paddr_index = mapcache->last_entry->paddr_index;
+        reventry->size = entry->size;
+        QTAILQ_INSERT_HEAD(&mapcache->locked_entries, reventry, next);
+    }
+
+    trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset);
+    return mapcache->last_entry->vaddr_base + address_offset;
+}
+
+uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size,
+                       uint8_t lock, bool dma)
+{
+    uint8_t *p;
+
+    mapcache_lock();
+    p = xen_map_cache_unlocked(phys_addr, size, lock, dma);
+    mapcache_unlock();
+    return p;
+}
+
+ram_addr_t xen_ram_addr_from_mapcache(void *ptr)
+{
+    MapCacheEntry *entry = NULL;
+    MapCacheRev *reventry;
+    hwaddr paddr_index;
+    hwaddr size;
+    ram_addr_t raddr;
+    int found = 0;
+
+    mapcache_lock();
+    QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
+        if (reventry->vaddr_req == ptr) {
+            paddr_index = reventry->paddr_index;
+            size = reventry->size;
+            found = 1;
+            break;
+        }
+    }
+    if (!found) {
+        fprintf(stderr, "%s, could not find %p\n", __func__, ptr);
+        QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
+            DPRINTF("   "HWADDR_FMT_plx" -> %p is present\n", reventry->paddr_index,
+                    reventry->vaddr_req);
+        }
+        abort();
+        return 0;
+    }
+
+    entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
+    while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
+        entry = entry->next;
+    }
+    if (!entry) {
+        DPRINTF("Trying to find address %p that is not in the mapcache!\n", ptr);
+        raddr = 0;
+    } else {
+        raddr = (reventry->paddr_index << MCACHE_BUCKET_SHIFT) +
+             ((unsigned long) ptr - (unsigned long) entry->vaddr_base);
+    }
+    mapcache_unlock();
+    return raddr;
+}
+
+static void xen_invalidate_map_cache_entry_unlocked(uint8_t *buffer)
+{
+    MapCacheEntry *entry = NULL, *pentry = NULL;
+    MapCacheRev *reventry;
+    hwaddr paddr_index;
+    hwaddr size;
+    int found = 0;
+
+    QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
+        if (reventry->vaddr_req == buffer) {
+            paddr_index = reventry->paddr_index;
+            size = reventry->size;
+            found = 1;
+            break;
+        }
+    }
+    if (!found) {
+        DPRINTF("%s, could not find %p\n", __func__, buffer);
+        QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
+            DPRINTF("   "HWADDR_FMT_plx" -> %p is present\n", reventry->paddr_index, reventry->vaddr_req);
+        }
+        return;
+    }
+    QTAILQ_REMOVE(&mapcache->locked_entries, reventry, next);
+    g_free(reventry);
+
+    if (mapcache->last_entry != NULL &&
+        mapcache->last_entry->paddr_index == paddr_index) {
+        mapcache->last_entry = NULL;
+    }
+
+    entry = &mapcache->entry[paddr_index % mapcache->nr_buckets];
+    while (entry && (entry->paddr_index != paddr_index || entry->size != size)) {
+        pentry = entry;
+        entry = entry->next;
+    }
+    if (!entry) {
+        DPRINTF("Trying to unmap address %p that is not in the mapcache!\n", buffer);
+        return;
+    }
+    entry->lock--;
+    if (entry->lock > 0 || pentry == NULL) {
+        return;
+    }
+
+    pentry->next = entry->next;
+    ram_block_notify_remove(entry->vaddr_base, entry->size, entry->size);
+    if (munmap(entry->vaddr_base, entry->size) != 0) {
+        perror("unmap fails");
+        exit(-1);
+    }
+    g_free(entry->valid_mapping);
+    g_free(entry);
+}
+
+void xen_invalidate_map_cache_entry(uint8_t *buffer)
+{
+    mapcache_lock();
+    xen_invalidate_map_cache_entry_unlocked(buffer);
+    mapcache_unlock();
+}
+
+void xen_invalidate_map_cache(void)
+{
+    unsigned long i;
+    MapCacheRev *reventry;
+
+    /* Flush pending AIO before destroying the mapcache */
+    bdrv_drain_all();
+
+    mapcache_lock();
+
+    QTAILQ_FOREACH(reventry, &mapcache->locked_entries, next) {
+        if (!reventry->dma) {
+            continue;
+        }
+        fprintf(stderr, "Locked DMA mapping while invalidating mapcache!"
+                " "HWADDR_FMT_plx" -> %p is present\n",
+                reventry->paddr_index, reventry->vaddr_req);
+    }
+
+    for (i = 0; i < mapcache->nr_buckets; i++) {
+        MapCacheEntry *entry = &mapcache->entry[i];
+
+        if (entry->vaddr_base == NULL) {
+            continue;
+        }
+        if (entry->lock > 0) {
+            continue;
+        }
+
+        if (munmap(entry->vaddr_base, entry->size) != 0) {
+            perror("unmap fails");
+            exit(-1);
+        }
+
+        entry->paddr_index = 0;
+        entry->vaddr_base = NULL;
+        entry->size = 0;
+        g_free(entry->valid_mapping);
+        entry->valid_mapping = NULL;
+    }
+
+    mapcache->last_entry = NULL;
+
+    mapcache_unlock();
+}
+
+static uint8_t *xen_replace_cache_entry_unlocked(hwaddr old_phys_addr,
+                                                 hwaddr new_phys_addr,
+                                                 hwaddr size)
+{
+    MapCacheEntry *entry;
+    hwaddr address_index, address_offset;
+    hwaddr test_bit_size, cache_size = size;
+
+    address_index  = old_phys_addr >> MCACHE_BUCKET_SHIFT;
+    address_offset = old_phys_addr & (MCACHE_BUCKET_SIZE - 1);
+
+    assert(size);
+    /* test_bit_size is always a multiple of XC_PAGE_SIZE */
+    test_bit_size = size + (old_phys_addr & (XC_PAGE_SIZE - 1));
+    if (test_bit_size % XC_PAGE_SIZE) {
+        test_bit_size += XC_PAGE_SIZE - (test_bit_size % XC_PAGE_SIZE);
+    }
+    cache_size = size + address_offset;
+    if (cache_size % MCACHE_BUCKET_SIZE) {
+        cache_size += MCACHE_BUCKET_SIZE - (cache_size % MCACHE_BUCKET_SIZE);
+    }
+
+    entry = &mapcache->entry[address_index % mapcache->nr_buckets];
+    while (entry && !(entry->paddr_index == address_index &&
+                      entry->size == cache_size)) {
+        entry = entry->next;
+    }
+    if (!entry) {
+        DPRINTF("Trying to update an entry for "HWADDR_FMT_plx \
+                "that is not in the mapcache!\n", old_phys_addr);
+        return NULL;
+    }
+
+    address_index  = new_phys_addr >> MCACHE_BUCKET_SHIFT;
+    address_offset = new_phys_addr & (MCACHE_BUCKET_SIZE - 1);
+
+    fprintf(stderr, "Replacing a dummy mapcache entry for "HWADDR_FMT_plx \
+            " with "HWADDR_FMT_plx"\n", old_phys_addr, new_phys_addr);
+
+    xen_remap_bucket(entry, entry->vaddr_base,
+                     cache_size, address_index, false);
+    if (!test_bits(address_offset >> XC_PAGE_SHIFT,
+                test_bit_size >> XC_PAGE_SHIFT,
+                entry->valid_mapping)) {
+        DPRINTF("Unable to update a mapcache entry for "HWADDR_FMT_plx"!\n",
+                old_phys_addr);
+        return NULL;
+    }
+
+    return entry->vaddr_base + address_offset;
+}
+
+uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr,
+                                 hwaddr new_phys_addr,
+                                 hwaddr size)
+{
+    uint8_t *p;
+
+    mapcache_lock();
+    p = xen_replace_cache_entry_unlocked(old_phys_addr, new_phys_addr, size);
+    mapcache_unlock();
+    return p;
+}