Re: [Qemu-devel] [PATCH V3 6/6] virtio-pci: unbreak queue_enable read

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Fri,  6 Nov 2015 16:02:49 +0800
Jason Wang <jasowang@redhat.com> wrote:

> Guest always get zero when reading queue_enable. This violates
> spec. Fixing this by setting the queue_enable to true during any guest
> writing and setting it to zero during reset.
> 
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  hw/virtio/virtio-pci.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index e4449da..52a9e33 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1384,6 +1384,7 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
>                         proxy->vqs[vdev->queue_sel].avail[0],
>                         ((uint64_t)proxy->vqs[vdev->queue_sel].used[1]) << 32 |
>                         proxy->vqs[vdev->queue_sel].used[0]);
> +        proxy->vqs[vdev->queue_sel].enabled = 1;

Hm. Spec says that the driver MUST NOT write 0 here. Does this need a
check?

<Also, I think you can remove the 'TODO' comment - this should be
handled now.>

>          break;
>      case VIRTIO_PCI_COMMON_Q_DESCLO:
>          proxy->vqs[vdev->queue_sel].desc[0] = val;
> @@ -1831,9 +1832,15 @@ static void virtio_pci_reset(DeviceState *qdev)
>  {
>      VirtIOPCIProxy *proxy = VIRTIO_PCI(qdev);
>      VirtioBusState *bus = VIRTIO_BUS(&proxy->bus);
> +    int i;
> +
>      virtio_pci_stop_ioeventfd(proxy);
>      virtio_bus_reset(bus);
>      msix_unuse_all_vectors(&proxy->pci_dev);
> +
> +    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
> +        proxy->vqs[i].enabled = 0;
> +    }
>  }
> 
>  static Property virtio_pci_properties[] = {

Otherwise, this looks good to me.