Re: [PATCH] virtio-pci: fix queue_enable write

[Jason Wang <jasowang@redhat.com>]

On 2020/6/10 下午12:16, Michael S. Tsirkin wrote:
> On Wed, Jun 10, 2020 at 10:03:28AM +0800, Jason Wang wrote:
>> On 2020/6/9 下午11:43, Michael S. Tsirkin wrote:
>>> On Fri, May 29, 2020 at 11:07:28AM +0800, Jason Wang wrote:
>>>> Spec said: The driver uses this to selectively prevent the device from
>>>> executing requests from this virtqueue. 1 - enabled; 0 - disabled.
>>>>
>>>> Though write 0 to queue_enable is forbidden by the sepc, we should not
>>> spec?
>>
>> Chapter 4.1.4.3.2 said:
>>
>> "
>>
>> The driver MUST NOT write a 0 to queue_enable.
>>
>> "
>>
>
> I mean you misspelled spec as sepc :)


Oh, right.

Will fix.

Thanks


>
>>>> assume that the value is 1.
>>>>
>>>> Fix this by ignoring the write value other than 1.
>>>>
>>>> Cc: Michael S. Tsirkin <mst@redhat.com>
>>>> Cc: Stefan Hajnoczi <stefanha@redhat.com>
>>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>> Do we want to call virtio_error here so we can figure out something's wrong?
>>
>> That looks better. Will do.
>>
>> Thanks
>>
>>
>>>
>>>
>>>> ---
>>>>    hw/virtio/virtio-pci.c | 10 ++++++----
>>>>    1 file changed, 6 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
>>>> index d028c17c24..b3558eeaee 100644
>>>> --- a/hw/virtio/virtio-pci.c
>>>> +++ b/hw/virtio/virtio-pci.c
>>>> @@ -1273,16 +1273,18 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
>>>>            virtio_queue_set_vector(vdev, vdev->queue_sel, val);
>>>>            break;
>>>>        case VIRTIO_PCI_COMMON_Q_ENABLE:
>>>> -        virtio_queue_set_num(vdev, vdev->queue_sel,
>>>> -                             proxy->vqs[vdev->queue_sel].num);
>>>> -        virtio_queue_set_rings(vdev, vdev->queue_sel,
>>>> +        if (val == 1) {
>>>> +            virtio_queue_set_num(vdev, vdev->queue_sel,
>>>> +                                 proxy->vqs[vdev->queue_sel].num);
>>>> +            virtio_queue_set_rings(vdev, vdev->queue_sel,
>>>>                           ((uint64_t)proxy->vqs[vdev->queue_sel].desc[1]) << 32 |
>>>>                           proxy->vqs[vdev->queue_sel].desc[0],
>>>>                           ((uint64_t)proxy->vqs[vdev->queue_sel].avail[1]) << 32 |
>>>>                           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;
>>>> +            proxy->vqs[vdev->queue_sel].enabled = 1;
>>>> +        }
>>>>            break;
>>>>        case VIRTIO_PCI_COMMON_Q_DESCLO:
>>>>            proxy->vqs[vdev->queue_sel].desc[0] = val;
>>>> -- 
>>>> 2.20.1