On Mon, Aug 15, 2022 at 01:34:41AM -0700, Andres Freund wrote:
> Hi,
>
> On August 15, 2022 1:28:29 AM PDT, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> >On Mon, Aug 15, 2022 at 01:15:27AM -0700, Andres Freund wrote:
> >> Hi,
> >>
> >> On 2022-08-15 03:51:34 -0400, Michael S. Tsirkin wrote:
> >> > It is possible that GCP gets confused if ring size is smaller than the
> >> > device maximum simply because no one did it in the past.
> >> >
> >> > So I pushed just the revert of 762faee5a267 to the test branch.
> >> > Could you give it a spin?
> >>
> >> Seems to fix the issue, at least to the extent I can determine at 1am... :)
> >>
> >> Greetings,
> >>
> >> Andres Freund
> >
> >So you tested this:
> >
> >commit 13df5a7eaeb22561d39354b576bc98a7e2c389f9 (HEAD, kernel.org/test)
> >Author: Michael S. Tsirkin <mst@xxxxxxxxxx>
> >Date: Mon Aug 15 03:44:38 2022 -0400
> >
> > Revert "virtio_net: set the default max ring size by find_vqs()"
> >
> > This reverts commit 762faee5a2678559d3dc09d95f8f2c54cd0466a7.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> >
> >and it fixes both issues right? No crashes no networking issue?
>
> Correct. I only did limited testing, but it's survived far longer / more reboots than anything since the commit.
>
> Andres
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
OK so this gives us a quick revert as a solution for now.
Next, I would appreciate it if you just try this simple hack.
If it crashes we either have a long standing problem in virtio
code or more likely a gcp bug where it can't handle smaller
rings than what device requestes.
Thanks!
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index f7965c5dd36b..bdd5f481570b 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -314,6 +314,9 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
if (!size || size > num)
size = num;
+ if (size > 1024)
+ size = 1024;
+
if (size & (size - 1)) {
dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", size);
return ERR_PTR(-EINVAL);
--
MST
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