[Qemu-devel] [PULL 0/7] Block patches

[Qemu-devel] [PULL 0/7] Block patches

[Stefan Hajnoczi]

The following changes since commit 4b59f39bc9a03afcc74b2fa28da7c3189fca507c:

  Merge remote-tracking branch 'remotes/mjt/tags/pull-trivial-patches-2015-11-06' into staging (2015-11-06 12:50:24 +0000)

are available in the git repository at:

  git://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to 6f707181b1bd6ccf2d2fd9397039c7ef6fa4a9fd:

  blockdev: acquire AioContext in hmp_commit() (2015-11-06 15:41:00 +0000)

----------------------------------------------------------------

----------------------------------------------------------------

Denis V. Lunev (1):
  monitor: add missed aio_context_acquire into vm_completion call

Fam Zheng (3):
  aio: Introduce aio_external_disabled
  aio: Introduce aio_context_setup
  aio: Introduce aio-epoll.c

Michael S. Tsirkin (2):
  dataplane: simplify indirect descriptor read
  dataplane: support non-contigious s/g

Stefan Hajnoczi (1):
  blockdev: acquire AioContext in hmp_commit()

 aio-posix.c                 | 188 +++++++++++++++++++++++++++++++++++++++++++-
 aio-win32.c                 |   4 +
 async.c                     |  13 ++-
 blockdev.c                  |  12 ++-
 hw/virtio/dataplane/vring.c |  96 ++++++++++++++--------
 include/block/aio.h         |  24 ++++++
 monitor.c                   |  11 ++-
 7 files changed, 309 insertions(+), 39 deletions(-)

-- 
2.5.0

[Qemu-devel] [PULL 1/7] dataplane: simplify indirect descriptor read

[Stefan Hajnoczi]

From: "Michael S. Tsirkin" <mst@redhat.com>

Use address_space_read to make sure we handle the case of an indirect
descriptor crossing DIMM boundary correctly.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 1446047243-3221-1-git-send-email-mst@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/virtio/dataplane/vring.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 68f1994..0b92fcf 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -257,6 +257,21 @@ 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 +299,16 @@ 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(); */
-- 
2.5.0

[Qemu-devel] [PULL 2/7] dataplane: support non-contigious s/g

[Stefan Hajnoczi]

From: "Michael S. Tsirkin" <mst@redhat.com>

bring_map currently fails if one of the entries it's mapping is
contigious in GPA but not HVA address space.  Introduce a mapped_len
parameter so it can handle this, returning the actual mapped length.

This will still fail if there's no space left in the sg, but luckily max
queue size in use is currently 256, while max sg size is 1024, so we
should be OK even is all entries happen to cross a single DIMM boundary.

Won't work well with very small DIMM sizes, unfortunately:
e.g. this will fail with 4K DIMMs where a single
request might span a large number of DIMMs.

Let's hope these are uncommon - at least we are not breaking things.

Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Reported-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 1446047243-3221-2-git-send-email-mst@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/virtio/dataplane/vring.c | 68 ++++++++++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 22 deletions(-)

diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 0b92fcf..23f667e 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -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;
+        }
 
-    /* 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 = len;
+        *addr++ = desc->addr;
+        desc->len -= len;
+        desc->addr += len;
+        *num += 1;
     }
 
-    /* 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;
 }
 
-- 
2.5.0

[Qemu-devel] [PULL 3/7] aio: Introduce aio_external_disabled

[Stefan Hajnoczi]

From: Fam Zheng <famz@redhat.com>

This allows AioContext users to check the enable/disable state of
external clients.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1446177989-6702-2-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/block/aio.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/block/aio.h b/include/block/aio.h
index 92efc5e..cab7c76 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -406,6 +406,17 @@ static inline void aio_enable_external(AioContext *ctx)
 }
 
 /**
+ * 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
  * @is_external: Whether or not the checked node is an external event source.
-- 
2.5.0

[Qemu-devel] [PULL 4/7] aio: Introduce aio_context_setup

[Stefan Hajnoczi]

From: Fam Zheng <famz@redhat.com>

This is the place to initialize platform specific bits of AioContext.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1446177989-6702-3-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 aio-posix.c         |  4 ++++
 aio-win32.c         |  4 ++++
 async.c             | 13 +++++++++++--
 include/block/aio.h |  8 ++++++++
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/aio-posix.c b/aio-posix.c
index 0467f23..5bff3cd 100644
--- a/aio-posix.c
+++ b/aio-posix.c
@@ -302,3 +302,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
 
     return progress;
 }
+
+void aio_context_setup(AioContext *ctx, Error **errp)
+{
+}
diff --git a/aio-win32.c b/aio-win32.c
index 43c4c79..cdc4456 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -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)
+{
+}
diff --git a/async.c b/async.c
index 9589e4b..e106072 100644
--- a/async.c
+++ b/async.c
@@ -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)
diff --git a/include/block/aio.h b/include/block/aio.h
index cab7c76..9ffecf7 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -429,4 +429,12 @@ 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
-- 
2.5.0

[Qemu-devel] [PULL 5/7] aio: Introduce aio-epoll.c

[Stefan Hajnoczi]

From: Fam Zheng <famz@redhat.com>

To minimize code duplication, epoll is hooked into aio-posix's
aio_poll() instead of rolling its own. This approach also has both
compile-time and run-time switchability.

1) When QEMU starts with a small number of fds in the event loop, ppoll
is used.

2) When QEMU starts with a big number of fds, or when more devices are
hot plugged, epoll kicks in when the number of fds hits the threshold.

3) Some fds may not support epoll, such as tty based stdio. In this
case, it falls back to ppoll.

A rough benchmark with scsi-disk on virtio-scsi dataplane (epoll gets
enabled from 64 onward). Numbers are in MB/s.

===============================================
             |     master     |     epoll
             |                |
scsi disks # | read    randrw | read    randrw
-------------|----------------|----------------
1            | 86      36     | 92      45
8            | 87      43     | 86      41
64           | 71      32     | 70      38
128          | 48      24     | 58      31
256          | 37      19     | 57      28
===============================================

To comply with aio_{disable,enable}_external, we always use ppoll when
aio_external_disabled() is true.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1446177989-6702-4-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 aio-posix.c         | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 include/block/aio.h |   5 ++
 2 files changed, 188 insertions(+), 1 deletion(-)

diff --git a/aio-posix.c b/aio-posix.c
index 5bff3cd..06148a9 100644
--- a/aio-posix.c
+++ b/aio-posix.c
@@ -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);
     }
@@ -305,4 +478,13 @@ bool aio_poll(AioContext *ctx, bool blocking)
 
 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
 }
diff --git a/include/block/aio.h b/include/block/aio.h
index 9ffecf7..7791200 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -124,6 +124,11 @@ struct AioContext {
     QEMUTimerListGroup tlg;
 
     int external_disable_cnt;
+#ifdef CONFIG_EPOLL
+    int epollfd;
+    bool epoll_enabled;
+    bool epoll_available;
+#endif
 };
 
 /**
-- 
2.5.0

[Qemu-devel] [PULL 6/7] monitor: add missed aio_context_acquire into vm_completion call

[Stefan Hajnoczi]

From: "Denis V. Lunev" <den@openvz.org>

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Luiz Capitulino <lcapitulino@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 monitor.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/monitor.c b/monitor.c
index 6cd747f..3295840 100644
--- a/monitor.c
+++ b/monitor.c
@@ -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;
+        aio_context_acquire(ctx);
+        if (bdrv_can_snapshot(bs)) {
+            ok = bdrv_query_snapshot_info_list(bs, &snapshots, NULL) == 0;
         }
-        if (bdrv_query_snapshot_info_list(bs, &snapshots, NULL)) {
+        aio_context_release(ctx);
+        if (!ok) {
             continue;
         }
+
         snapshot = snapshots;
         while (snapshot) {
             char *completion = snapshot->value->name;
-- 
2.5.0

[Qemu-devel] [PULL 7/7] blockdev: acquire AioContext in hmp_commit()

[Stefan Hajnoczi]

This one slipped through.  Although we acquire AioContext when
committing all devices we don't for just a single device.

AioContext must be acquired before calling bdrv_*() functions to
synchronize access with other threads that may be using the AioContext.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 blockdev.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index 8b8bfa9..97be42f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -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,
-- 
2.5.0

Re: [Qemu-devel] [PULL 0/7] Block patches

[Peter Maydell]

On 6 November 2015 at 17:52, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> The following changes since commit 4b59f39bc9a03afcc74b2fa28da7c3189fca507c:
>
>   Merge remote-tracking branch 'remotes/mjt/tags/pull-trivial-patches-2015-11-06' into staging (2015-11-06 12:50:24 +0000)
>
> are available in the git repository at:
>
>   git://github.com/stefanha/qemu.git tags/block-pull-request
>
> for you to fetch changes up to 6f707181b1bd6ccf2d2fd9397039c7ef6fa4a9fd:
>
>   blockdev: acquire AioContext in hmp_commit() (2015-11-06 15:41:00 +0000)
>
> ----------------------------------------------------------------

Build failure on OSX :-(

/Users/pm215/src/qemu-for-merges/aio-posix.c  CC    block/qcow.o
:442:37: error: no member named 'epollfd' in 'struct AioContext'
        epoll_handler.pfd.fd = ctx->epollfd;
                               ~~~  ^

thanks
-- PMM

Re: [Qemu-devel] [PULL 0/7] Block patches

[Fam Zheng]

On Fri, 11/06 18:07, Peter Maydell wrote:
> On 6 November 2015 at 17:52, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > The following changes since commit 4b59f39bc9a03afcc74b2fa28da7c3189fca507c:
> >
> >   Merge remote-tracking branch 'remotes/mjt/tags/pull-trivial-patches-2015-11-06' into staging (2015-11-06 12:50:24 +0000)
> >
> > are available in the git repository at:
> >
> >   git://github.com/stefanha/qemu.git tags/block-pull-request
> >
> > for you to fetch changes up to 6f707181b1bd6ccf2d2fd9397039c7ef6fa4a9fd:
> >
> >   blockdev: acquire AioContext in hmp_commit() (2015-11-06 15:41:00 +0000)
> >
> > ----------------------------------------------------------------
> 
> Build failure on OSX :-(
> 
> /Users/pm215/src/qemu-for-merges/aio-posix.c  CC    block/qcow.o
> :442:37: error: no member named 'epollfd' in 'struct AioContext'
>         epoll_handler.pfd.fd = ctx->epollfd;
>                                ~~~  ^
> 

:(

I think it is harmless to always include this member in AioContext. Stefan,
could you squash this into patch 5?  Thanks!

Fam

---

diff --git a/include/block/aio.h b/include/block/aio.h
index 91737d5..735f1f8 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -124,11 +124,9 @@ struct AioContext {
     QEMUTimerListGroup tlg;
 
     int external_disable_cnt;
-#ifdef CONFIG_EPOLL
     int epollfd;
     bool epoll_enabled;
     bool epoll_available;
-#endif
 };
                                                                               
 /**                                                                           

Re: [Qemu-devel] [PULL 0/7] Block patches

[Markus Armbruster]

Fam Zheng <famz@redhat.com> writes:

> On Fri, 11/06 18:07, Peter Maydell wrote:
>> On 6 November 2015 at 17:52, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>> > The following changes since commit 4b59f39bc9a03afcc74b2fa28da7c3189fca507c:
>> >
>> >   Merge remote-tracking branch
>> > 'remotes/mjt/tags/pull-trivial-patches-2015-11-06' into staging
>> > (2015-11-06 12:50:24 +0000)
>> >
>> > are available in the git repository at:
>> >
>> >   git://github.com/stefanha/qemu.git tags/block-pull-request
>> >
>> > for you to fetch changes up to 6f707181b1bd6ccf2d2fd9397039c7ef6fa4a9fd:
>> >
>> >   blockdev: acquire AioContext in hmp_commit() (2015-11-06 15:41:00 +0000)
>> >
>> > ----------------------------------------------------------------
>> 
>> Build failure on OSX :-(
>> 
>> /Users/pm215/src/qemu-for-merges/aio-posix.c  CC    block/qcow.o
>> :442:37: error: no member named 'epollfd' in 'struct AioContext'
>>         epoll_handler.pfd.fd = ctx->epollfd;
>>                                ~~~  ^
>> 
>
> :(
>
> I think it is harmless to always include this member in AioContext. Stefan,
> could you squash this into patch 5?  Thanks!
>
> Fam
>
> ---
>
> diff --git a/include/block/aio.h b/include/block/aio.h
> index 91737d5..735f1f8 100644
> --- a/include/block/aio.h
> +++ b/include/block/aio.h
> @@ -124,11 +124,9 @@ struct AioContext {
>      QEMUTimerListGroup tlg;
>  
>      int external_disable_cnt;
> -#ifdef CONFIG_EPOLL
>      int epollfd;
>      bool epoll_enabled;
>      bool epoll_available;
> -#endif
>  };

Replace by the ifdeffery by a comment pointing to CONFIG_EPOLL, perhaps?

Re: [Qemu-devel] [PULL 0/7] Block patches

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 1885 bytes --]

On Mon, Nov 09, 2015 at 08:35:56AM +0100, Markus Armbruster wrote:
> Fam Zheng <famz@redhat.com> writes:
> 
> > On Fri, 11/06 18:07, Peter Maydell wrote:
> >> On 6 November 2015 at 17:52, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >> > The following changes since commit 4b59f39bc9a03afcc74b2fa28da7c3189fca507c:
> >> >
> >> >   Merge remote-tracking branch
> >> > 'remotes/mjt/tags/pull-trivial-patches-2015-11-06' into staging
> >> > (2015-11-06 12:50:24 +0000)
> >> >
> >> > are available in the git repository at:
> >> >
> >> >   git://github.com/stefanha/qemu.git tags/block-pull-request
> >> >
> >> > for you to fetch changes up to 6f707181b1bd6ccf2d2fd9397039c7ef6fa4a9fd:
> >> >
> >> >   blockdev: acquire AioContext in hmp_commit() (2015-11-06 15:41:00 +0000)
> >> >
> >> > ----------------------------------------------------------------
> >> 
> >> Build failure on OSX :-(
> >> 
> >> /Users/pm215/src/qemu-for-merges/aio-posix.c  CC    block/qcow.o
> >> :442:37: error: no member named 'epollfd' in 'struct AioContext'
> >>         epoll_handler.pfd.fd = ctx->epollfd;
> >>                                ~~~  ^
> >> 
> >
> > :(
> >
> > I think it is harmless to always include this member in AioContext. Stefan,
> > could you squash this into patch 5?  Thanks!
> >
> > Fam
> >
> > ---
> >
> > diff --git a/include/block/aio.h b/include/block/aio.h
> > index 91737d5..735f1f8 100644
> > --- a/include/block/aio.h
> > +++ b/include/block/aio.h
> > @@ -124,11 +124,9 @@ struct AioContext {
> >      QEMUTimerListGroup tlg;
> >  
> >      int external_disable_cnt;
> > -#ifdef CONFIG_EPOLL
> >      int epollfd;
> >      bool epoll_enabled;
> >      bool epoll_available;
> > -#endif
> >  };
> 
> Replace by the ifdeffery by a comment pointing to CONFIG_EPOLL, perhaps?

Done.  Will send a v2 pull request.

Stefan

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