Re: [Qemu-devel] [PATCH 3/9] virtio-blk: fix disabled mode

[tu bo]

Hi Paolo:

On 03/30/2016 08:48 PM, Paolo Bonzini wrote:

The missing check on dataplane_disabled caused a segmentation
fault in notify_guest_bh, because s->guest_notifier was NULL.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
  hw/block/dataplane/virtio-blk.c | 7 +++----
  hw/block/virtio-blk.c           | 2 +-
  include/hw/virtio/virtio-blk.h  | 1 +
  3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 0d76110..378feb3 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -28,7 +28,6 @@
  struct VirtIOBlockDataPlane {
      bool starting;
      bool stopping;
-    bool disabled;

      VirtIOBlkConf *conf;

@@ -233,7 +232,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
    fail_host_notifier:
      k->set_guest_notifiers(qbus->parent, 1, false);
    fail_guest_notifiers:
-    s->disabled = true;
+    vblk->dataplane_disabled = true;
      s->starting = false;
      vblk->dataplane_started = true;
  }
@@ -250,8 +249,8 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
      }

      /* Better luck next time. */
-    if (s->disabled) {
-        s->disabled = false;
+    if (vblk->dataplane_disabled) {
+        vblk->dataplane_disabled = false;
          vblk->dataplane_started = false;
          return;
      }
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index d0b8248..77221c1 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -53,7 +53,7 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, 
unsigned char status)

      stb_p(&req->in->status, status);
      virtqueue_push(s->vq, &req->elem, req->in_len);
-    if (s->dataplane) {
+    if (s->dataplane_started && !s->dataplane_disabled) {
          virtio_blk_data_plane_notify(s->dataplane);
      } else {
          virtio_notify(vdev, s->vq);
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 5cb66cd..073c632 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -53,6 +53,7 @@ typedef struct VirtIOBlock {
      unsigned short sector_mask;
      bool original_wce;
      VMChangeStateEntry *change;
+    bool dataplane_disabled;
      bool dataplane_started;
      int reentrancy_test;

There is no "int reentrancy_test;" in the latest qemu master. thx

      struct VirtIOBlockDataPlane *dataplane;