* [PATCH V2] virtio-pci: fix queue_enable write
@ 2020-06-10 5:43 Jason Wang
2020-06-10 8:57 ` Stefano Garzarella
2020-06-11 8:41 ` Stefan Hajnoczi
0 siblings, 2 replies; 6+ messages in thread
From: Jason Wang @ 2020-06-10 5:43 UTC (permalink / raw)
To: mst, qemu-devel; +Cc: Jason Wang, stefanha
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 spec, we should not
assume that the value is 1.
Fix this by ignore the write value other than 1.
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
Changes from V1:
- fix typo
- warn wrong value through virtio_error
---
hw/virtio/virtio-pci.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index d028c17c24..7bc8c1c056 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1273,16 +1273,20 @@ 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;
+ } else {
+ virtio_error(vdev, "wrong value for queue_enable %"PRIx64, val);
+ }
break;
case VIRTIO_PCI_COMMON_Q_DESCLO:
proxy->vqs[vdev->queue_sel].desc[0] = val;
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH V2] virtio-pci: fix queue_enable write
2020-06-10 5:43 [PATCH V2] virtio-pci: fix queue_enable write Jason Wang
@ 2020-06-10 8:57 ` Stefano Garzarella
2020-06-10 9:42 ` Michael S. Tsirkin
2020-06-11 8:41 ` Stefan Hajnoczi
1 sibling, 1 reply; 6+ messages in thread
From: Stefano Garzarella @ 2020-06-10 8:57 UTC (permalink / raw)
To: Jason Wang; +Cc: qemu-devel, stefanha, mst
On Wed, Jun 10, 2020 at 01:43:51PM +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 spec, we should not
> assume that the value is 1.
>
> Fix this by ignore the write value other than 1.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> Changes from V1:
> - fix typo
> - warn wrong value through virtio_error
> ---
> hw/virtio/virtio-pci.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index d028c17c24..7bc8c1c056 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1273,16 +1273,20 @@ 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) {
Does it have to be 1 or can it be any value other than 0?
Thanks,
Stefano
> + 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;
> + } else {
> + virtio_error(vdev, "wrong value for queue_enable %"PRIx64, val);
> + }
> break;
> case VIRTIO_PCI_COMMON_Q_DESCLO:
> proxy->vqs[vdev->queue_sel].desc[0] = val;
> --
> 2.20.1
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] virtio-pci: fix queue_enable write
2020-06-10 8:57 ` Stefano Garzarella
@ 2020-06-10 9:42 ` Michael S. Tsirkin
2020-06-10 9:52 ` Stefano Garzarella
0 siblings, 1 reply; 6+ messages in thread
From: Michael S. Tsirkin @ 2020-06-10 9:42 UTC (permalink / raw)
To: Stefano Garzarella; +Cc: Jason Wang, qemu-devel, stefanha
On Wed, Jun 10, 2020 at 10:57:26AM +0200, Stefano Garzarella wrote:
> On Wed, Jun 10, 2020 at 01:43:51PM +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 spec, we should not
> > assume that the value is 1.
> >
> > Fix this by ignore the write value other than 1.
> >
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> > Changes from V1:
> > - fix typo
> > - warn wrong value through virtio_error
> > ---
> > hw/virtio/virtio-pci.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index d028c17c24..7bc8c1c056 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -1273,16 +1273,20 @@ 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) {
>
> Does it have to be 1 or can it be any value other than 0?
>
> Thanks,
> Stefano
spec says 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;
> > + } else {
> > + virtio_error(vdev, "wrong value for queue_enable %"PRIx64, val);
> > + }
> > break;
> > case VIRTIO_PCI_COMMON_Q_DESCLO:
> > proxy->vqs[vdev->queue_sel].desc[0] = val;
> > --
> > 2.20.1
> >
> >
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] virtio-pci: fix queue_enable write
2020-06-10 9:42 ` Michael S. Tsirkin
@ 2020-06-10 9:52 ` Stefano Garzarella
2020-06-11 3:05 ` Jason Wang
0 siblings, 1 reply; 6+ messages in thread
From: Stefano Garzarella @ 2020-06-10 9:52 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: Jason Wang, qemu-devel, stefanha
On Wed, Jun 10, 2020 at 05:42:54AM -0400, Michael S. Tsirkin wrote:
> On Wed, Jun 10, 2020 at 10:57:26AM +0200, Stefano Garzarella wrote:
> > On Wed, Jun 10, 2020 at 01:43:51PM +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 spec, we should not
> > > assume that the value is 1.
> > >
> > > Fix this by ignore the write value other than 1.
> > >
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > > ---
> > > Changes from V1:
> > > - fix typo
> > > - warn wrong value through virtio_error
> > > ---
> > > hw/virtio/virtio-pci.c | 12 ++++++++----
> > > 1 file changed, 8 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > > index d028c17c24..7bc8c1c056 100644
> > > --- a/hw/virtio/virtio-pci.c
> > > +++ b/hw/virtio/virtio-pci.c
> > > @@ -1273,16 +1273,20 @@ 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) {
> >
> > Does it have to be 1 or can it be any value other than 0?
> >
> > Thanks,
> > Stefano
>
> spec says 1
I was confused by "The driver MUST NOT write a 0 to queue_enable.",
interpreting it as "can write anything other than 0".
But as Jason also wrote in the commit message, the driver should write
1 to enable, so
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Thanks,
Stefano
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2] virtio-pci: fix queue_enable write
2020-06-10 9:52 ` Stefano Garzarella
@ 2020-06-11 3:05 ` Jason Wang
0 siblings, 0 replies; 6+ messages in thread
From: Jason Wang @ 2020-06-11 3:05 UTC (permalink / raw)
To: Stefano Garzarella, Michael S. Tsirkin; +Cc: qemu-devel, stefanha
On 2020/6/10 下午5:52, Stefano Garzarella wrote:
> On Wed, Jun 10, 2020 at 05:42:54AM -0400, Michael S. Tsirkin wrote:
>> On Wed, Jun 10, 2020 at 10:57:26AM +0200, Stefano Garzarella wrote:
>>> On Wed, Jun 10, 2020 at 01:43:51PM +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 spec, we should not
>>>> assume that the value is 1.
>>>>
>>>> Fix this by ignore the write value other than 1.
>>>>
>>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>>> ---
>>>> Changes from V1:
>>>> - fix typo
>>>> - warn wrong value through virtio_error
>>>> ---
>>>> hw/virtio/virtio-pci.c | 12 ++++++++----
>>>> 1 file changed, 8 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
>>>> index d028c17c24..7bc8c1c056 100644
>>>> --- a/hw/virtio/virtio-pci.c
>>>> +++ b/hw/virtio/virtio-pci.c
>>>> @@ -1273,16 +1273,20 @@ 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) {
>>> Does it have to be 1 or can it be any value other than 0?
>>>
>>> Thanks,
>>> Stefano
>> spec says 1
> I was confused by "The driver MUST NOT write a 0 to queue_enable.",
> interpreting it as "can write anything other than 0".
Yes, the spec is unclear about what happens if we write a value other
than 0 or 1.
Maybe we should clarify that only 1 is allowed. Or writing value other
than 1 may cause unexpected result.
>
> But as Jason also wrote in the commit message, the driver should write
> 1 to enable, so
>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Thanks
>
> Thanks,
> Stefano
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] virtio-pci: fix queue_enable write
2020-06-10 5:43 [PATCH V2] virtio-pci: fix queue_enable write Jason Wang
2020-06-10 8:57 ` Stefano Garzarella
@ 2020-06-11 8:41 ` Stefan Hajnoczi
1 sibling, 0 replies; 6+ messages in thread
From: Stefan Hajnoczi @ 2020-06-11 8:41 UTC (permalink / raw)
To: Jason Wang; +Cc: qemu-devel, mst
[-- Attachment #1: Type: text/plain, Size: 667 bytes --]
On Wed, Jun 10, 2020 at 01:43:51PM +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 spec, we should not
> assume that the value is 1.
>
> Fix this by ignore the write value other than 1.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> Changes from V1:
> - fix typo
> - warn wrong value through virtio_error
> ---
> hw/virtio/virtio-pci.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2020-06-10 5:43 [PATCH V2] virtio-pci: fix queue_enable write Jason Wang
2020-06-10 8:57 ` Stefano Garzarella
2020-06-10 9:42 ` Michael S. Tsirkin
2020-06-10 9:52 ` Stefano Garzarella
2020-06-11 3:05 ` Jason Wang
2020-06-11 8:41 ` Stefan Hajnoczi
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