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

# gpg: Signature made Mon 09 Nov 2015 10:08:17 GMT using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/block-pull-request:
  blockdev: acquire AioContext in hmp_commit()
  monitor: add missed aio_context_acquire into vm_completion call
  aio: Introduce aio-epoll.c
  aio: Introduce aio_context_setup
  aio: Introduce aio_external_disabled
  dataplane: support non-contigious s/g
  dataplane: simplify indirect descriptor read

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell 2015-11-09 11:20:51 +00:00
commit 9d5c1dc117
7 changed files with 311 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

188
aio-posix.c
View File

@ -17,6 +17,9 @@
#include "block/block.h"
#include "qemu/queue.h"
#include "qemu/sockets.h"
#ifdef CONFIG_EPOLL
#include <sys/epoll.h>
#endif
struct AioHandler
{
@ -29,6 +32,162 @@ struct AioHandler
QLIST_ENTRY(AioHandler) node;
};
#ifdef CONFIG_EPOLL
/* The fd number threashold to switch to epoll */
#define EPOLL_ENABLE_THRESHOLD 64
static void aio_epoll_disable(AioContext *ctx)
{
ctx->epoll_available = false;
if (!ctx->epoll_enabled) {
return;
}
ctx->epoll_enabled = false;
close(ctx->epollfd);
}
static inline int epoll_events_from_pfd(int pfd_events)
{
return (pfd_events & G_IO_IN ? EPOLLIN : 0) |
(pfd_events & G_IO_OUT ? EPOLLOUT : 0) |
(pfd_events & G_IO_HUP ? EPOLLHUP : 0) |
(pfd_events & G_IO_ERR ? EPOLLERR : 0);
}
static bool aio_epoll_try_enable(AioContext *ctx)
{
AioHandler *node;
struct epoll_event event;
QLIST_FOREACH(node, &ctx->aio_handlers, node) {
int r;
if (node->deleted || !node->pfd.events) {
continue;
}
event.events = epoll_events_from_pfd(node->pfd.events);
event.data.ptr = node;
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_ADD, node->pfd.fd, &event);
if (r) {
return false;
}
}
ctx->epoll_enabled = true;
return true;
}
static void aio_epoll_update(AioContext *ctx, AioHandler *node, bool is_new)
{
struct epoll_event event;
int r;
if (!ctx->epoll_enabled) {
return;
}
if (!node->pfd.events) {
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_DEL, node->pfd.fd, &event);
if (r) {
aio_epoll_disable(ctx);
}
} else {
event.data.ptr = node;
event.events = epoll_events_from_pfd(node->pfd.events);
if (is_new) {
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_ADD, node->pfd.fd, &event);
if (r) {
aio_epoll_disable(ctx);
}
} else {
r = epoll_ctl(ctx->epollfd, EPOLL_CTL_MOD, node->pfd.fd, &event);
if (r) {
aio_epoll_disable(ctx);
}
}
}
}
static int aio_epoll(AioContext *ctx, GPollFD *pfds,
unsigned npfd, int64_t timeout)
{
AioHandler *node;
int i, ret = 0;
struct epoll_event events[128];
assert(npfd == 1);
assert(pfds[0].fd == ctx->epollfd);
if (timeout > 0) {
ret = qemu_poll_ns(pfds, npfd, timeout);
}
if (timeout <= 0 || ret > 0) {
ret = epoll_wait(ctx->epollfd, events,
sizeof(events) / sizeof(events[0]),
timeout);
if (ret <= 0) {
goto out;
}
for (i = 0; i < ret; i++) {
int ev = events[i].events;
node = events[i].data.ptr;
node->pfd.revents = (ev & EPOLLIN ? G_IO_IN : 0) |
(ev & EPOLLOUT ? G_IO_OUT : 0) |
(ev & EPOLLHUP ? G_IO_HUP : 0) |
(ev & EPOLLERR ? G_IO_ERR : 0);
}
}
out:
return ret;
}
static bool aio_epoll_enabled(AioContext *ctx)
{
/* Fall back to ppoll when external clients are disabled. */
return !aio_external_disabled(ctx) && ctx->epoll_enabled;
}
static bool aio_epoll_check_poll(AioContext *ctx, GPollFD *pfds,
unsigned npfd, int64_t timeout)
{
if (!ctx->epoll_available) {
return false;
}
if (aio_epoll_enabled(ctx)) {
return true;
}
if (npfd >= EPOLL_ENABLE_THRESHOLD) {
if (aio_epoll_try_enable(ctx)) {
return true;
} else {
aio_epoll_disable(ctx);
}
}
return false;
}
#else
static void aio_epoll_update(AioContext *ctx, AioHandler *node, bool is_new)
{
}
static int aio_epoll(AioContext *ctx, GPollFD *pfds,
unsigned npfd, int64_t timeout)
{
assert(false);
}
static bool aio_epoll_enabled(AioContext *ctx)
{
return false;
}
static bool aio_epoll_check_poll(AioContext *ctx, GPollFD *pfds,
unsigned npfd, int64_t timeout)
{
return false;
}
#endif
static AioHandler *find_aio_handler(AioContext *ctx, int fd)
{
AioHandler *node;
@ -50,6 +209,7 @@ void aio_set_fd_handler(AioContext *ctx,
void *opaque)
{
AioHandler *node;
bool is_new = false;
node = find_aio_handler(ctx, fd);
@ -79,6 +239,7 @@ void aio_set_fd_handler(AioContext *ctx,
QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node);
g_source_add_poll(&ctx->source, &node->pfd);
is_new = true;
}
/* Update handler with latest information */
node->io_read = io_read;
@ -90,6 +251,7 @@ void aio_set_fd_handler(AioContext *ctx,
node->pfd.events |= (io_write ? G_IO_OUT | G_IO_ERR : 0);
}
aio_epoll_update(ctx, node, is_new);
aio_notify(ctx);
}
@ -262,6 +424,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
/* fill pollfds */
QLIST_FOREACH(node, &ctx->aio_handlers, node) {
if (!node->deleted && node->pfd.events
&& !aio_epoll_enabled(ctx)
&& aio_node_check(ctx, node->is_external)) {
add_pollfd(node);
}
@ -273,7 +436,17 @@ bool aio_poll(AioContext *ctx, bool blocking)
if (timeout) {
aio_context_release(ctx);
}
ret = qemu_poll_ns((GPollFD *)pollfds, npfd, timeout);
if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
AioHandler epoll_handler;
epoll_handler.pfd.fd = ctx->epollfd;
epoll_handler.pfd.events = G_IO_IN | G_IO_OUT | G_IO_HUP | G_IO_ERR;
npfd = 0;
add_pollfd(&epoll_handler);
ret = aio_epoll(ctx, pollfds, npfd, timeout);
} else {
ret = qemu_poll_ns(pollfds, npfd, timeout);
}
if (blocking) {
atomic_sub(&ctx->notify_me, 2);
}
@ -302,3 +475,16 @@ bool aio_poll(AioContext *ctx, bool blocking)
return progress;
}
void aio_context_setup(AioContext *ctx, Error **errp)
{
#ifdef CONFIG_EPOLL
assert(!ctx->epollfd);
ctx->epollfd = epoll_create1(EPOLL_CLOEXEC);
if (ctx->epollfd == -1) {
ctx->epoll_available = false;
} else {
ctx->epoll_available = true;
}
#endif
}

4
aio-win32.c
View File

@ -369,3 +369,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
aio_context_release(ctx);
return progress;
}
void aio_context_setup(AioContext *ctx, Error **errp)
{
}

13
async.c
View File

@ -325,12 +325,18 @@ AioContext *aio_context_new(Error **errp)
{
int ret;
AioContext *ctx;
Error *local_err = NULL;
ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
aio_context_setup(ctx, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto fail;
}
ret = event_notifier_init(&ctx->notifier, false);
if (ret < 0) {
g_source_destroy(&ctx->source);
error_setg_errno(errp, -ret, "Failed to initialize event notifier");
return NULL;
goto fail;
}
g_source_set_can_recurse(&ctx->source, true);
aio_set_event_notifier(ctx, &ctx->notifier,
@ -345,6 +351,9 @@ AioContext *aio_context_new(Error **errp)
ctx->notify_dummy_bh = aio_bh_new(ctx, notify_dummy_bh, NULL);
return ctx;
fail:
g_source_destroy(&ctx->source);
return NULL;
}
void aio_context_ref(AioContext *ctx)

12
blockdev.c
View File

@ -1120,6 +1120,9 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
if (!strcmp(device, "all")) {
ret = bdrv_commit_all();
} else {
BlockDriverState *bs;
AioContext *aio_context;
blk = blk_by_name(device);
if (!blk) {
monitor_printf(mon, "Device '%s' not found\n", device);
@ -1129,7 +1132,14 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
monitor_printf(mon, "Device '%s' has no medium\n", device);
return;
}
ret = bdrv_commit(blk_bs(blk));
bs = blk_bs(blk);
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
ret = bdrv_commit(bs);
aio_context_release(aio_context);
}
if (ret < 0) {
monitor_printf(mon, "'commit' error for '%s': %s\n", device,

98
hw/virtio/dataplane/vring.c
View File

@ -25,15 +25,30 @@
/* vring_map can be coupled with vring_unmap or (if you still have the
* value returned in *mr) memory_region_unref.
* Returns NULL on failure.
* Callers that can handle a partial mapping must supply mapped_len pointer to
* get the actual length mapped.
* Passing mapped_len == NULL requires either a full mapping or a failure.
*/
static void *vring_map(MemoryRegion **mr, hwaddr phys, hwaddr len,
static void *vring_map(MemoryRegion **mr, hwaddr phys,
hwaddr len, hwaddr *mapped_len,
bool is_write)
{
MemoryRegionSection section = memory_region_find(get_system_memory(), phys, len);
uint64_t size;
if (!section.mr || int128_get64(section.size) < len) {
if (!section.mr) {
goto out;
}
size = int128_get64(section.size);
assert(size);
/* Passing mapped_len == NULL requires either a full mapping or a failure. */
if (!mapped_len && size < len) {
goto out;
}
if (is_write && section.readonly) {
goto out;
}
@ -46,6 +61,10 @@ static void *vring_map(MemoryRegion **mr, hwaddr phys, hwaddr len,
goto out;
}
if (mapped_len) {
*mapped_len = MIN(size, len);
}
*mr = section.mr;
return memory_region_get_ram_ptr(section.mr) + section.offset_within_region;
@ -78,7 +97,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
addr = virtio_queue_get_desc_addr(vdev, n);
size = virtio_queue_get_desc_size(vdev, n);
/* Map the descriptor area as read only */
ptr = vring_map(&vring->mr_desc, addr, size, false);
ptr = vring_map(&vring->mr_desc, addr, size, NULL, false);
if (!ptr) {
error_report("Failed to map 0x%" HWADDR_PRIx " byte for vring desc "
"at 0x%" HWADDR_PRIx,
@ -92,7 +111,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
/* Add the size of the used_event_idx */
size += sizeof(uint16_t);
/* Map the driver area as read only */
ptr = vring_map(&vring->mr_avail, addr, size, false);
ptr = vring_map(&vring->mr_avail, addr, size, NULL, false);
if (!ptr) {
error_report("Failed to map 0x%" HWADDR_PRIx " byte for vring avail "
"at 0x%" HWADDR_PRIx,
@ -106,7 +125,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
/* Add the size of the avail_event_idx */
size += sizeof(uint16_t);
/* Map the device area as read-write */
ptr = vring_map(&vring->mr_used, addr, size, true);
ptr = vring_map(&vring->mr_used, addr, size, NULL, true);
if (!ptr) {
error_report("Failed to map 0x%" HWADDR_PRIx " byte for vring used "
"at 0x%" HWADDR_PRIx,
@ -206,6 +225,7 @@ static int get_desc(Vring *vring, VirtQueueElement *elem,
struct iovec *iov;
hwaddr *addr;
MemoryRegion *mr;
hwaddr len;
if (desc->flags & VRING_DESC_F_WRITE) {
num = &elem->in_num;
@ -224,26 +244,30 @@ static int get_desc(Vring *vring, VirtQueueElement *elem,
}
}
/* Stop for now if there are not enough iovecs available. */
if (*num >= VIRTQUEUE_MAX_SIZE) {
error_report("Invalid SG num: %u", *num);
return -EFAULT;
while (desc->len) {
/* Stop for now if there are not enough iovecs available. */
if (*num >= VIRTQUEUE_MAX_SIZE) {
error_report("Invalid SG num: %u", *num);
return -EFAULT;
}
iov->iov_base = vring_map(&mr, desc->addr, desc->len, &len,
desc->flags & VRING_DESC_F_WRITE);
if (!iov->iov_base) {
error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
(uint64_t)desc->addr, desc->len);
return -EFAULT;
}
/* The MemoryRegion is looked up again and unref'ed later, leave the
* ref in place. */
(iov++)->iov_len = len;
*addr++ = desc->addr;
desc->len -= len;
desc->addr += len;
*num += 1;
}
/* TODO handle non-contiguous memory across region boundaries */
iov->iov_base = vring_map(&mr, desc->addr, desc->len,
desc->flags & VRING_DESC_F_WRITE);
if (!iov->iov_base) {
error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
(uint64_t)desc->addr, desc->len);
return -EFAULT;
}
/* The MemoryRegion is looked up again and unref'ed later, leave the
* ref in place. */
iov->iov_len = desc->len;
*addr = desc->addr;
*num += 1;
return 0;
}
@ -257,6 +281,21 @@ static void copy_in_vring_desc(VirtIODevice *vdev,
host->next = virtio_lduw_p(vdev, &guest->next);
}
static bool read_vring_desc(VirtIODevice *vdev,
hwaddr guest,
struct vring_desc *host)
{
if (address_space_read(&address_space_memory, guest, MEMTXATTRS_UNSPECIFIED,
(uint8_t *)host, sizeof *host)) {
return false;
}
host->addr = virtio_tswap64(vdev, host->addr);
host->len = virtio_tswap32(vdev, host->len);
host->flags = virtio_tswap16(vdev, host->flags);
host->next = virtio_tswap16(vdev, host->next);
return true;
}
/* This is stolen from linux/drivers/vhost/vhost.c. */
static int get_indirect(VirtIODevice *vdev, Vring *vring,
VirtQueueElement *elem, struct vring_desc *indirect)
@ -284,23 +323,16 @@ static int get_indirect(VirtIODevice *vdev, Vring *vring,
}
do {
struct vring_desc *desc_ptr;
MemoryRegion *mr;
/* Translate indirect descriptor */
desc_ptr = vring_map(&mr,
indirect->addr + found * sizeof(desc),
sizeof(desc), false);
if (!desc_ptr) {
error_report("Failed to map indirect descriptor "
if (!read_vring_desc(vdev, indirect->addr + found * sizeof(desc),
&desc)) {
error_report("Failed to read indirect descriptor "
"addr %#" PRIx64 " len %zu",
(uint64_t)indirect->addr + found * sizeof(desc),
sizeof(desc));
vring->broken = true;
return -EFAULT;
}
copy_in_vring_desc(vdev, desc_ptr, &desc);
memory_region_unref(mr);
/* Ensure descriptor has been loaded before accessing fields */
barrier(); /* read_barrier_depends(); */

24
include/block/aio.h
View File

@ -124,6 +124,11 @@ struct AioContext {
QEMUTimerListGroup tlg;
int external_disable_cnt;
/* epoll(7) state used when built with CONFIG_EPOLL */
int epollfd;
bool epoll_enabled;
bool epoll_available;
};
/**
@ -405,6 +410,17 @@ static inline void aio_enable_external(AioContext *ctx)
atomic_dec(&ctx->external_disable_cnt);
}
/**
* aio_external_disabled:
* @ctx: the aio context
*
* Return true if the external clients are disabled.
*/
static inline bool aio_external_disabled(AioContext *ctx)
{
return atomic_read(&ctx->external_disable_cnt);
}
/**
* aio_node_check:
* @ctx: the aio context
@ -418,4 +434,12 @@ static inline bool aio_node_check(AioContext *ctx, bool is_external)
return !is_external || !atomic_read(&ctx->external_disable_cnt);
}
/**
* aio_context_setup:
* @ctx: the aio context
*
* Initialize the aio context.
*/
void aio_context_setup(AioContext *ctx, Error **errp);
#endif

13
monitor.c
View File

@ -3408,13 +3408,18 @@ static void vm_completion(ReadLineState *rs, const char *str)
readline_set_completion_index(rs, len);
while ((bs = bdrv_next(bs))) {
SnapshotInfoList *snapshots, *snapshot;
AioContext *ctx = bdrv_get_aio_context(bs);
bool ok = false;
if (!bdrv_can_snapshot(bs)) {
continue;
}
if (bdrv_query_snapshot_info_list(bs, &snapshots, NULL)) {
aio_context_acquire(ctx);
if (bdrv_can_snapshot(bs)) {
ok = bdrv_query_snapshot_info_list(bs, &snapshots, NULL) == 0;
}
aio_context_release(ctx);
if (!ok) {
continue;
}
snapshot = snapshots;
while (snapshot) {
char *completion = snapshot->value->name;