[Qemu-devel] [PULL 0/2] Block patches

[Qemu-devel] [PULL 0/2] Block patches

[Stefan Hajnoczi]

The following changes since commit 577caa2672ccde7352fda3ef17e44993de862f0e:

  Merge remote-tracking branch 'remotes/edgar/tags/edgar/mmio-exec-v2.for-upstream' into staging (2017-06-27 16:56:55 +0100)

are available in the git repository at:

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

for you to fetch changes up to 439778e6b4a20c8fe6a6a92a17013b09c4ae55d0:

  virtio-pci: use ioeventfd even when KVM is disabled (2017-06-28 13:18:53 +0100)

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

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

Stefan Hajnoczi (2):
  virtio-blk: trace vdev so devices can be distinguished
  virtio-pci: use ioeventfd even when KVM is disabled

 hw/block/virtio-blk.c  | 12 +++++++-----
 hw/virtio/virtio-pci.c |  2 +-
 hw/block/trace-events  | 10 +++++-----
 3 files changed, 13 insertions(+), 11 deletions(-)

-- 
2.9.4

[Qemu-devel] [PULL 1/2] virtio-blk: trace vdev so devices can be distinguished

[Stefan Hajnoczi]

It is hard to analyze trace logs with multiple virtio-blk devices
because none of the trace events include the VirtIODevice *vdev.

This patch adds vdev so it's clear which device a request is associated
with.

I considered using VirtIOBlock *s instead but VirtIODevice *vdev is more
general and may be correlated with generic virtio trace events like
virtio_set_status.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170614092930.11234-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/virtio-blk.c | 12 +++++++-----
 hw/block/trace-events | 10 +++++-----
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 604d37d..c0bd247 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -50,7 +50,7 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status)
     VirtIOBlock *s = req->dev;
     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 
-    trace_virtio_blk_req_complete(req, status);
+    trace_virtio_blk_req_complete(vdev, req, status);
 
     stb_p(&req->in->status, status);
     virtqueue_push(req->vq, &req->elem, req->in_len);
@@ -88,12 +88,13 @@ static void virtio_blk_rw_complete(void *opaque, int ret)
 {
     VirtIOBlockReq *next = opaque;
     VirtIOBlock *s = next->dev;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
 
     aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
     while (next) {
         VirtIOBlockReq *req = next;
         next = req->mr_next;
-        trace_virtio_blk_rw_complete(req, ret);
+        trace_virtio_blk_rw_complete(vdev, req, ret);
 
         if (req->qiov.nalloc != -1) {
             /* If nalloc is != 1 req->qiov is a local copy of the original
@@ -355,7 +356,8 @@ static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
             mrb->reqs[i - 1]->mr_next = mrb->reqs[i];
         }
 
-        trace_virtio_blk_submit_multireq(mrb, start, num_reqs,
+        trace_virtio_blk_submit_multireq(VIRTIO_DEVICE(mrb->reqs[start]->dev),
+                                         mrb, start, num_reqs,
                                          sector_num << BDRV_SECTOR_BITS,
                                          qiov->size, is_write);
         block_acct_merge_done(blk_get_stats(blk),
@@ -526,11 +528,11 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
 
         if (is_write) {
             qemu_iovec_init_external(&req->qiov, iov, out_num);
-            trace_virtio_blk_handle_write(req, req->sector_num,
+            trace_virtio_blk_handle_write(vdev, req, req->sector_num,
                                           req->qiov.size / BDRV_SECTOR_SIZE);
         } else {
             qemu_iovec_init_external(&req->qiov, in_iov, in_num);
-            trace_virtio_blk_handle_read(req, req->sector_num,
+            trace_virtio_blk_handle_read(vdev, req, req->sector_num,
                                          req->qiov.size / BDRV_SECTOR_SIZE);
         }
 
diff --git a/hw/block/trace-events b/hw/block/trace-events
index 65e83dc..c332c01 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -1,11 +1,11 @@
 # See docs/tracing.txt for syntax documentation.
 
 # hw/block/virtio-blk.c
-virtio_blk_req_complete(void *req, int status) "req %p status %d"
-virtio_blk_rw_complete(void *req, int ret) "req %p ret %d"
-virtio_blk_handle_write(void *req, uint64_t sector, size_t nsectors) "req %p sector %"PRIu64" nsectors %zu"
-virtio_blk_handle_read(void *req, uint64_t sector, size_t nsectors) "req %p sector %"PRIu64" nsectors %zu"
-virtio_blk_submit_multireq(void *mrb, int start, int num_reqs, uint64_t offset, size_t size, bool is_write) "mrb %p start %d num_reqs %d offset %"PRIu64" size %zu is_write %d"
+virtio_blk_req_complete(void *vdev, void *req, int status) "vdev %p req %p status %d"
+virtio_blk_rw_complete(void *vdev, void *req, int ret) "vdev %p req %p ret %d"
+virtio_blk_handle_write(void *vdev, void *req, uint64_t sector, size_t nsectors) "vdev %p req %p sector %"PRIu64" nsectors %zu"
+virtio_blk_handle_read(void *vdev, void *req, uint64_t sector, size_t nsectors) "vdev %p req %p sector %"PRIu64" nsectors %zu"
+virtio_blk_submit_multireq(void *vdev, void *mrb, int start, int num_reqs, uint64_t offset, size_t size, bool is_write) "vdev %p mrb %p start %d num_reqs %d offset %"PRIu64" size %zu is_write %d"
 
 # hw/block/hd-geometry.c
 hd_geometry_lchs_guess(void *blk, int cyls, int heads, int secs) "blk %p LCHS %d %d %d"
-- 
2.9.4

[Qemu-devel] [PULL 2/2] virtio-pci: use ioeventfd even when KVM is disabled

[Stefan Hajnoczi]

Old kvm.ko versions only supported a tiny number of ioeventfds so
virtio-pci avoids ioeventfds when kvm_has_many_ioeventfds() returns 0.

Do not check kvm_has_many_ioeventfds() when KVM is disabled since it
always returns 0.  Since commit 8c56c1a592b5092d91da8d8943c17777d6462a6f
("memory: emulate ioeventfd") it has been possible to use ioeventfds in
qtest or TCG mode.

This patch makes -device virtio-blk-pci,iothread=iothread0 work even
when KVM is disabled.

I have tested that virtio-blk-pci works under TCG both with and without
iothread.

This patch fixes qemu-iotests 068, which was accidentally merged early
despite the dependency on ioeventfd.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20170615163813.7255-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/virtio/virtio-pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 20d6a08..301920e 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1740,7 +1740,7 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
     bool pcie_port = pci_bus_is_express(pci_dev->bus) &&
                      !pci_bus_is_root(pci_dev->bus);
 
-    if (!kvm_has_many_ioeventfds()) {
+    if (kvm_enabled() && !kvm_has_many_ioeventfds()) {
         proxy->flags &= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
     }
 
-- 
2.9.4

Re: [Qemu-devel] [PULL 0/2] Block patches

[Stefan Hajnoczi]

On Wed, Jun 28, 2017 at 1:20 PM, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> The following changes since commit 577caa2672ccde7352fda3ef17e44993de862f0e:
>
>   Merge remote-tracking branch 'remotes/edgar/tags/edgar/mmio-exec-v2.for-upstream' into staging (2017-06-27 16:56:55 +0100)
>
> are available in the git repository at:
>
>   git://github.com/stefanha/qemu.git tags/block-pull-request
>
> for you to fetch changes up to 439778e6b4a20c8fe6a6a92a17013b09c4ae55d0:
>
>   virtio-pci: use ioeventfd even when KVM is disabled (2017-06-28 13:18:53 +0100)
>
> ----------------------------------------------------------------
>
> ----------------------------------------------------------------
>
> Stefan Hajnoczi (2):
>   virtio-blk: trace vdev so devices can be distinguished
>   virtio-pci: use ioeventfd even when KVM is disabled

NACK

I missed the mail discussing the virtio-scsi-test assertion failure
caused by "virtio-pci: use ioeventfd even when KVM is disabled".

Stefan