[Qemu-devel] [PULL 0/6] Block patches

[Qemu-devel] [PULL 0/6] Block patches

[Kevin Wolf]

The following changes since commit 63fb2590839162afdf14d7c0ee02d460766c0956:

  Merge branch 'target-arm.next' of git://git.linaro.org/people/pmaydell/qemu-arm (2013-01-12 12:47:07 +0000)

are available in the git repository at:

  git://repo.or.cz/qemu/kevin.git for-anthony

Liu Yuan (1):
      sheepdog: implement direct write semantics

Paolo Bonzini (2):
      block: do not probe zero-sized disks
      raw-posix: fix bdrv_aio_ioctl

Stefan Hajnoczi (3):
      block: make qiov_is_aligned() public
      dataplane: extract virtio-blk read/write processing into do_rdwr_cmd()
      dataplane: handle misaligned virtio-blk requests

 block.c                   |   18 +++++++++++-
 block/raw-posix.c         |   28 +----------------
 block/sheepdog.c          |   70 +++++++++++++++++++++++++-------------------
 hw/dataplane/virtio-blk.c |   71 ++++++++++++++++++++++++++++++++++++++-------
 include/block/block.h     |    1 +
 5 files changed, 120 insertions(+), 68 deletions(-)

[Qemu-devel] [PATCH 1/6] block: do not probe zero-sized disks

[Kevin Wolf]

From: Paolo Bonzini <pbonzini@redhat.com>

A blank CD or DVD is visible as a zero-sized disks.  Probing such
disks will lead to an EIO and a failure to start the VM.  Treating
them as raw is a better solution.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c
index 60873ea..14f8202 100644
--- a/block.c
+++ b/block.c
@@ -527,7 +527,7 @@ static int find_image_format(BlockDriverState *bs, const char *filename,
     int ret = 0;
 
     /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
-    if (bs->sg || !bdrv_is_inserted(bs)) {
+    if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
         drv = bdrv_find_format("raw");
         if (!drv) {
             ret = -ENOENT;
-- 
1.7.6.5

[Qemu-devel] [PATCH 2/6] sheepdog: implement direct write semantics

[Kevin Wolf]

From: Liu Yuan <tailai.ly@taobao.com>

Sheepdog supports both writeback/writethrough write but has not yet supported
DIRECTIO semantics which bypass the cache completely even if Sheepdog daemon is
set up with cache enabled.

Suppose cache is enabled on Sheepdog daemon size, the new cache control is

cache=writeback # enable the writeback semantics for write
cache=writethrough # enable the emulated writethrough semantics for write
cache=directsync # disable cache competely

Guest WCE toggling on the run time to toggle writeback/writethrough is also
supported.

Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/sheepdog.c |   70 ++++++++++++++++++++++++++++++-----------------------
 1 files changed, 40 insertions(+), 30 deletions(-)

diff --git a/block/sheepdog.c b/block/sheepdog.c
index e821746..462c4b2 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -36,7 +36,8 @@
 
 #define SD_FLAG_CMD_WRITE    0x01
 #define SD_FLAG_CMD_COW      0x02
-#define SD_FLAG_CMD_CACHE    0x04
+#define SD_FLAG_CMD_CACHE    0x04 /* Writeback mode for cache */
+#define SD_FLAG_CMD_DIRECT   0x08 /* Don't use cache */
 
 #define SD_RES_SUCCESS       0x00 /* Success */
 #define SD_RES_UNKNOWN       0x01 /* Unknown error */
@@ -293,7 +294,7 @@ typedef struct BDRVSheepdogState {
 
     char name[SD_MAX_VDI_LEN];
     bool is_snapshot;
-    bool cache_enabled;
+    uint32_t cache_flags;
 
     char *addr;
     char *port;
@@ -977,8 +978,8 @@ static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
         hdr.flags = SD_FLAG_CMD_WRITE | flags;
     }
 
-    if (s->cache_enabled) {
-        hdr.flags |= SD_FLAG_CMD_CACHE;
+    if (s->cache_flags) {
+        hdr.flags |= s->cache_flags;
     }
 
     hdr.oid = oid;
@@ -1023,7 +1024,7 @@ static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
 
 static int read_write_object(int fd, char *buf, uint64_t oid, int copies,
                              unsigned int datalen, uint64_t offset,
-                             bool write, bool create, bool cache)
+                             bool write, bool create, uint32_t cache_flags)
 {
     SheepdogObjReq hdr;
     SheepdogObjRsp *rsp = (SheepdogObjRsp *)&hdr;
@@ -1047,9 +1048,7 @@ static int read_write_object(int fd, char *buf, uint64_t oid, int copies,
         hdr.opcode = SD_OP_READ_OBJ;
     }
 
-    if (cache) {
-        hdr.flags |= SD_FLAG_CMD_CACHE;
-    }
+    hdr.flags |= cache_flags;
 
     hdr.oid = oid;
     hdr.data_length = datalen;
@@ -1072,18 +1071,19 @@ static int read_write_object(int fd, char *buf, uint64_t oid, int copies,
 }
 
 static int read_object(int fd, char *buf, uint64_t oid, int copies,
-                       unsigned int datalen, uint64_t offset, bool cache)
+                       unsigned int datalen, uint64_t offset,
+                       uint32_t cache_flags)
 {
     return read_write_object(fd, buf, oid, copies, datalen, offset, false,
-                             false, cache);
+                             false, cache_flags);
 }
 
 static int write_object(int fd, char *buf, uint64_t oid, int copies,
                         unsigned int datalen, uint64_t offset, bool create,
-                        bool cache)
+                        uint32_t cache_flags)
 {
     return read_write_object(fd, buf, oid, copies, datalen, offset, true,
-                             create, cache);
+                             create, cache_flags);
 }
 
 static int sd_open(BlockDriverState *bs, const char *filename, int flags)
@@ -1118,12 +1118,22 @@ static int sd_open(BlockDriverState *bs, const char *filename, int flags)
         goto out;
     }
 
-    s->cache_enabled = true;
-    s->flush_fd = connect_to_sdog(s->addr, s->port);
-    if (s->flush_fd < 0) {
-        error_report("failed to connect");
-        ret = s->flush_fd;
-        goto out;
+    /*
+     * QEMU block layer emulates writethrough cache as 'writeback + flush', so
+     * we always set SD_FLAG_CMD_CACHE (writeback cache) as default.
+     */
+    s->cache_flags = SD_FLAG_CMD_CACHE;
+    if (flags & BDRV_O_NOCACHE) {
+        s->cache_flags = SD_FLAG_CMD_DIRECT;
+    }
+
+    if (s->cache_flags == SD_FLAG_CMD_CACHE) {
+        s->flush_fd = connect_to_sdog(s->addr, s->port);
+        if (s->flush_fd < 0) {
+            error_report("failed to connect");
+            ret = s->flush_fd;
+            goto out;
+        }
     }
 
     if (snapid || tag[0] != '\0') {
@@ -1140,7 +1150,7 @@ static int sd_open(BlockDriverState *bs, const char *filename, int flags)
 
     buf = g_malloc(SD_INODE_SIZE);
     ret = read_object(fd, buf, vid_to_vdi_oid(vid), 0, SD_INODE_SIZE, 0,
-                      s->cache_enabled);
+                      s->cache_flags);
 
     closesocket(fd);
 
@@ -1387,7 +1397,7 @@ static void sd_close(BlockDriverState *bs)
 
     qemu_aio_set_fd_handler(s->fd, NULL, NULL, NULL, NULL);
     closesocket(s->fd);
-    if (s->cache_enabled) {
+    if (s->cache_flags) {
         closesocket(s->flush_fd);
     }
     g_free(s->addr);
@@ -1423,7 +1433,7 @@ static int sd_truncate(BlockDriverState *bs, int64_t offset)
     datalen = SD_INODE_SIZE - sizeof(s->inode.data_vdi_id);
     s->inode.vdi_size = offset;
     ret = write_object(fd, (char *)&s->inode, vid_to_vdi_oid(s->inode.vdi_id),
-                       s->inode.nr_copies, datalen, 0, false, s->cache_enabled);
+                       s->inode.nr_copies, datalen, 0, false, s->cache_flags);
     close(fd);
 
     if (ret < 0) {
@@ -1506,7 +1516,7 @@ static int sd_create_branch(BDRVSheepdogState *s)
     }
 
     ret = read_object(fd, buf, vid_to_vdi_oid(vid), s->inode.nr_copies,
-                      SD_INODE_SIZE, 0, s->cache_enabled);
+                      SD_INODE_SIZE, 0, s->cache_flags);
 
     closesocket(fd);
 
@@ -1707,7 +1717,7 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
     int ret;
     unsigned int wlen = 0, rlen = 0;
 
-    if (!s->cache_enabled) {
+    if (s->cache_flags != SD_FLAG_CMD_CACHE) {
         return 0;
     }
 
@@ -1723,7 +1733,7 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
     if (rsp->result == SD_RES_INVALID_PARMS) {
         dprintf("disable write cache since the server doesn't support it\n");
 
-        s->cache_enabled = false;
+        s->cache_flags = SD_FLAG_CMD_DIRECT;
         closesocket(s->flush_fd);
         return 0;
     }
@@ -1774,7 +1784,7 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     }
 
     ret = write_object(fd, (char *)&s->inode, vid_to_vdi_oid(s->inode.vdi_id),
-                       s->inode.nr_copies, datalen, 0, false, s->cache_enabled);
+                       s->inode.nr_copies, datalen, 0, false, s->cache_flags);
     if (ret < 0) {
         error_report("failed to write snapshot's inode.");
         goto cleanup;
@@ -1791,7 +1801,7 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     inode = (SheepdogInode *)g_malloc(datalen);
 
     ret = read_object(fd, (char *)inode, vid_to_vdi_oid(new_vid),
-                      s->inode.nr_copies, datalen, 0, s->cache_enabled);
+                      s->inode.nr_copies, datalen, 0, s->cache_flags);
 
     if (ret < 0) {
         error_report("failed to read new inode info. %s", strerror(errno));
@@ -1845,7 +1855,7 @@ static int sd_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
 
     buf = g_malloc(SD_INODE_SIZE);
     ret = read_object(fd, buf, vid_to_vdi_oid(vid), s->inode.nr_copies,
-                      SD_INODE_SIZE, 0, s->cache_enabled);
+                      SD_INODE_SIZE, 0, s->cache_flags);
 
     closesocket(fd);
 
@@ -1942,7 +1952,7 @@ static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
         /* we don't need to read entire object */
         ret = read_object(fd, (char *)&inode, vid_to_vdi_oid(vid),
                           0, SD_INODE_SIZE - sizeof(inode.data_vdi_id), 0,
-                          s->cache_enabled);
+                          s->cache_flags);
 
         if (ret) {
             continue;
@@ -2003,11 +2013,11 @@ static int do_load_save_vmstate(BDRVSheepdogState *s, uint8_t *data,
         if (load) {
             ret = read_object(fd, (char *)data, vmstate_oid,
                               s->inode.nr_copies, data_len, offset,
-                              s->cache_enabled);
+                              s->cache_flags);
         } else {
             ret = write_object(fd, (char *)data, vmstate_oid,
                                s->inode.nr_copies, data_len, offset, create,
-                               s->cache_enabled);
+                               s->cache_flags);
         }
 
         if (ret < 0) {
-- 
1.7.6.5

[Qemu-devel] [PATCH 3/6] raw-posix: fix bdrv_aio_ioctl

[Kevin Wolf]

From: Paolo Bonzini <pbonzini@redhat.com>

When the raw-posix aio=thread code was moved from posix-aio-compat.c
to block/raw-posix.c, there was an unintended change to the ioctl code.
The code used to return the ioctl command, which posix_aio_read()
would later morph into a zero.  This hack is not necessary anymore,
and in fact breaks scsi-generic (which expects a zero return code).
Remove it.

Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/raw-posix.c |   10 +---------
 1 files changed, 1 insertions(+), 9 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 87d888e..0e705ba 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -455,15 +455,7 @@ static ssize_t handle_aiocb_ioctl(RawPosixAIOData *aiocb)
         return -errno;
     }
 
-    /*
-     * This looks weird, but the aio code only considers a request
-     * successful if it has written the full number of bytes.
-     *
-     * Now we overload aio_nbytes as aio_ioctl_cmd for the ioctl command,
-     * so in fact we return the ioctl command here to make posix_aio_read()
-     * happy..
-     */
-    return aiocb->aio_nbytes;
+    return 0;
 }
 
 static ssize_t handle_aiocb_flush(RawPosixAIOData *aiocb)
-- 
1.7.6.5

[Qemu-devel] [PATCH 4/6] block: make qiov_is_aligned() public

[Kevin Wolf]

From: Stefan Hajnoczi <stefanha@redhat.com>

The qiov_is_aligned() function checks whether a QEMUIOVector meets a
BlockDriverState's alignment requirements.  This is needed by
virtio-blk-data-plane so:

1. Move the function from block/raw-posix.c to block/block.c.
2. Make it public in block/block.h.
3. Rename to bdrv_qiov_is_aligned().
4. Change return type from int to bool.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c               |   16 ++++++++++++++++
 block/raw-posix.c     |   18 +-----------------
 include/block/block.h |    1 +
 3 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/block.c b/block.c
index 14f8202..b5e64ec 100644
--- a/block.c
+++ b/block.c
@@ -4313,6 +4313,22 @@ void *qemu_blockalign(BlockDriverState *bs, size_t size)
     return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size);
 }
 
+/*
+ * Check if all memory in this vector is sector aligned.
+ */
+bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
+{
+    int i;
+
+    for (i = 0; i < qiov->niov; i++) {
+        if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable)
 {
     int64_t bitmap_size;
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 0e705ba..c3d7fda 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -430,22 +430,6 @@ static void raw_reopen_abort(BDRVReopenState *state)
 #endif
 */
 
-/*
- * Check if all memory in this vector is sector aligned.
- */
-static int qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
-{
-    int i;
-
-    for (i = 0; i < qiov->niov; i++) {
-        if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) {
-            return 0;
-        }
-    }
-
-    return 1;
-}
-
 static ssize_t handle_aiocb_ioctl(RawPosixAIOData *aiocb)
 {
     int ret;
@@ -714,7 +698,7 @@ static BlockDriverAIOCB *raw_aio_submit(BlockDriverState *bs,
      * driver that it needs to copy the buffer.
      */
     if ((bs->open_flags & BDRV_O_NOCACHE)) {
-        if (!qiov_is_aligned(bs, qiov)) {
+        if (!bdrv_qiov_is_aligned(bs, qiov)) {
             type |= QEMU_AIO_MISALIGNED;
 #ifdef CONFIG_LINUX_AIO
         } else if (s->use_aio) {
diff --git a/include/block/block.h b/include/block/block.h
index 0719339..ffd1936 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -349,6 +349,7 @@ void bdrv_img_create(const char *filename, const char *fmt,
 
 void bdrv_set_buffer_alignment(BlockDriverState *bs, int align);
 void *qemu_blockalign(BlockDriverState *bs, size_t size);
+bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 
 #define BDRV_SECTORS_PER_DIRTY_CHUNK 2048
 
-- 
1.7.6.5

[Qemu-devel] [PATCH 5/6] dataplane: extract virtio-blk read/write processing into do_rdwr_cmd()

[Kevin Wolf]

From: Stefan Hajnoczi <stefanha@redhat.com>

Extract code for read/write command processing into do_rdwr_cmd().  This
brings together pieces that are spread across process_request().

The real motivation is to set the stage for handling misaligned
requests, which the next patch tackles.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/dataplane/virtio-blk.c |   31 ++++++++++++++++++++-----------
 1 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/hw/dataplane/virtio-blk.c b/hw/dataplane/virtio-blk.c
index 4c4ad84..a6696b8 100644
--- a/hw/dataplane/virtio-blk.c
+++ b/hw/dataplane/virtio-blk.c
@@ -130,6 +130,22 @@ static void do_get_id_cmd(VirtIOBlockDataPlane *s,
     complete_request_early(s, head, inhdr, VIRTIO_BLK_S_OK);
 }
 
+static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
+                       struct iovec *iov, unsigned int iov_cnt,
+                       long long offset, unsigned int head,
+                       QEMUIOVector *inhdr)
+{
+    struct iocb *iocb;
+
+    iocb = ioq_rdwr(&s->ioqueue, read, iov, iov_cnt, offset);
+
+    /* Fill in virtio block metadata needed for completion */
+    VirtIOBlockRequest *req = container_of(iocb, VirtIOBlockRequest, iocb);
+    req->head = head;
+    req->inhdr = inhdr;
+    return 0;
+}
+
 static int process_request(IOQueue *ioq, struct iovec iov[],
                            unsigned int out_num, unsigned int in_num,
                            unsigned int head)
@@ -139,7 +155,6 @@ static int process_request(IOQueue *ioq, struct iovec iov[],
     struct virtio_blk_outhdr outhdr;
     QEMUIOVector *inhdr;
     size_t in_size;
-    struct iocb *iocb;
 
     /* Copy in outhdr */
     if (unlikely(iov_to_buf(iov, out_num, 0, &outhdr,
@@ -167,12 +182,12 @@ static int process_request(IOQueue *ioq, struct iovec iov[],
 
     switch (outhdr.type) {
     case VIRTIO_BLK_T_IN:
-        iocb = ioq_rdwr(ioq, true, in_iov, in_num, outhdr.sector * 512);
-        break;
+        do_rdwr_cmd(s, true, in_iov, in_num, outhdr.sector * 512, head, inhdr);
+        return 0;
 
     case VIRTIO_BLK_T_OUT:
-        iocb = ioq_rdwr(ioq, false, iov, out_num, outhdr.sector * 512);
-        break;
+        do_rdwr_cmd(s, false, iov, out_num, outhdr.sector * 512, head, inhdr);
+        return 0;
 
     case VIRTIO_BLK_T_SCSI_CMD:
         /* TODO support SCSI commands */
@@ -198,12 +213,6 @@ static int process_request(IOQueue *ioq, struct iovec iov[],
         g_slice_free(QEMUIOVector, inhdr);
         return -EFAULT;
     }
-
-    /* Fill in virtio block metadata needed for completion */
-    VirtIOBlockRequest *req = container_of(iocb, VirtIOBlockRequest, iocb);
-    req->head = head;
-    req->inhdr = inhdr;
-    return 0;
 }
 
 static void handle_notify(EventHandler *handler)
-- 
1.7.6.5

[Qemu-devel] [PATCH 6/6] dataplane: handle misaligned virtio-blk requests

[Kevin Wolf]

From: Stefan Hajnoczi <stefanha@redhat.com>

O_DIRECT on Linux has alignment requirements on I/O buffers and
misaligned requests result in -EINVAL.  The Linux virtio_blk guest
driver usually submits aligned requests so I forgot to handle misaligned
requests.

It turns out that virtio-win guest drivers submit misaligned requests.
Handle them using a bounce buffer that meets alignment requirements.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/dataplane/virtio-blk.c |   40 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/hw/dataplane/virtio-blk.c b/hw/dataplane/virtio-blk.c
index a6696b8..1f7346e 100644
--- a/hw/dataplane/virtio-blk.c
+++ b/hw/dataplane/virtio-blk.c
@@ -34,6 +34,8 @@ typedef struct {
     struct iocb iocb;               /* Linux AIO control block */
     QEMUIOVector *inhdr;            /* iovecs for virtio_blk_inhdr */
     unsigned int head;              /* vring descriptor index */
+    struct iovec *bounce_iov;       /* used if guest buffers are unaligned */
+    QEMUIOVector *read_qiov;        /* for read completion /w bounce buffer */
 } VirtIOBlockRequest;
 
 struct VirtIOBlockDataPlane {
@@ -89,6 +91,18 @@ static void complete_request(struct iocb *iocb, ssize_t ret, void *opaque)
 
     trace_virtio_blk_data_plane_complete_request(s, req->head, ret);
 
+    if (req->read_qiov) {
+        assert(req->bounce_iov);
+        qemu_iovec_from_buf(req->read_qiov, 0, req->bounce_iov->iov_base, len);
+        qemu_iovec_destroy(req->read_qiov);
+        g_slice_free(QEMUIOVector, req->read_qiov);
+    }
+
+    if (req->bounce_iov) {
+        qemu_vfree(req->bounce_iov->iov_base);
+        g_slice_free(struct iovec, req->bounce_iov);
+    }
+
     qemu_iovec_from_buf(req->inhdr, 0, &hdr, sizeof(hdr));
     qemu_iovec_destroy(req->inhdr);
     g_slice_free(QEMUIOVector, req->inhdr);
@@ -136,6 +150,30 @@ static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
                        QEMUIOVector *inhdr)
 {
     struct iocb *iocb;
+    QEMUIOVector qiov;
+    struct iovec *bounce_iov = NULL;
+    QEMUIOVector *read_qiov = NULL;
+
+    qemu_iovec_init_external(&qiov, iov, iov_cnt);
+    if (!bdrv_qiov_is_aligned(s->blk->conf.bs, &qiov)) {
+        void *bounce_buffer = qemu_blockalign(s->blk->conf.bs, qiov.size);
+
+        if (read) {
+            /* Need to copy back from bounce buffer on completion */
+            read_qiov = g_slice_new(QEMUIOVector);
+            qemu_iovec_init(read_qiov, iov_cnt);
+            qemu_iovec_concat_iov(read_qiov, iov, iov_cnt, 0, qiov.size);
+        } else {
+            qemu_iovec_to_buf(&qiov, 0, bounce_buffer, qiov.size);
+        }
+
+        /* Redirect I/O to aligned bounce buffer */
+        bounce_iov = g_slice_new(struct iovec);
+        bounce_iov->iov_base = bounce_buffer;
+        bounce_iov->iov_len = qiov.size;
+        iov = bounce_iov;
+        iov_cnt = 1;
+    }
 
     iocb = ioq_rdwr(&s->ioqueue, read, iov, iov_cnt, offset);
 
@@ -143,6 +181,8 @@ static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
     VirtIOBlockRequest *req = container_of(iocb, VirtIOBlockRequest, iocb);
     req->head = head;
     req->inhdr = inhdr;
+    req->bounce_iov = bounce_iov;
+    req->read_qiov = read_qiov;
     return 0;
 }
 
-- 
1.7.6.5

Re: [Qemu-devel] [PULL 0/6] Block patches

[Anthony Liguori]

Pulled.  Thanks.

Regards,

Anthony Liguori