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 <address@hidden>
> ---
>   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;