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

[Jason Wang <jasowang@redhat.com>]

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.

"


>
>> 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
>