Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

[Filip Hejsek]

Hi,

I would like to request backporting 5326ab737a47 ("virtio_console: fix
order of fields cols and rows") to all LTS kernels.

I'm working on QEMU patches that add virtio console size support.
Without the fix, rows and columns will be swapped.

As far as I know, there are no device implementations that use the
wrong order and would by broken by the fix.

Note: A previous version [1] of the patch contained "Cc: stable" and
"Fixes:" tags, but they seem to have been accidentally left out from
the final version.

[1]: https://lore.kernel.org/all/20250320172654.624657-1-maxbr@linux.ibm.com/

Thanks,
Filip Hejsek

Re: Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

[Filip Hejsek]

On Thu, 2025-09-18 at 01:13 +0200, Filip Hejsek wrote:
> Hi,
> 
> I would like to request backporting 5326ab737a47 ("virtio_console: fix
> order of fields cols and rows") to all LTS kernels.
> 
> I'm working on QEMU patches that add virtio console size support.
> Without the fix, rows and columns will be swapped.
> 
> As far as I know, there are no device implementations that use the
> wrong order and would by broken by the fix.
> 
> Note: A previous version [1] of the patch contained "Cc: stable" and
> "Fixes:" tags, but they seem to have been accidentally left out from
> the final version.
> 
> [1]: https://lore.kernel.org/all/20250320172654.624657-1-maxbr@linux.ibm.com/
> 
> Thanks,
> Filip Hejsek

Sorry, that patch might actually end up being reverted, so please wait
until this clears up. We are still debating whether the Linux
implementation or the spec should be changed.

Best regards,
Filip Hejsek

Re: Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

[Michael S. Tsirkin]

On Thu, Sep 18, 2025 at 05:58:55PM +0200, Filip Hejsek wrote:
> On Thu, 2025-09-18 at 01:13 +0200, Filip Hejsek wrote:
> > Hi,
> > 
> > I would like to request backporting 5326ab737a47 ("virtio_console: fix
> > order of fields cols and rows") to all LTS kernels.
> > 
> > I'm working on QEMU patches that add virtio console size support.
> > Without the fix, rows and columns will be swapped.
> > 
> > As far as I know, there are no device implementations that use the
> > wrong order and would by broken by the fix.
> > 
> > Note: A previous version [1] of the patch contained "Cc: stable" and
> > "Fixes:" tags, but they seem to have been accidentally left out from
> > the final version.
> > 
> > [1]: https://lore.kernel.org/all/20250320172654.624657-1-maxbr@linux.ibm.com/
> > 
> > Thanks,
> > Filip Hejsek
> 
> Sorry, that patch might actually end up being reverted, so please wait
> until this clears up. We are still debating whether the Linux
> implementation or the spec should be changed.
> 
> Best regards,
> Filip Hejsek


OK I sent a spec patch to make it match Linux. Let's see what is
happening.

-- 
MST

Re: Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

[Michael S. Tsirkin]

On Thu, Sep 18, 2025 at 01:13:24AM +0200, Filip Hejsek wrote:
> Hi,
> 
> I would like to request backporting 5326ab737a47 ("virtio_console: fix
> order of fields cols and rows") to all LTS kernels.
> 
> I'm working on QEMU patches that add virtio console size support.
> Without the fix, rows and columns will be swapped.
> 
> As far as I know, there are no device implementations that use the
> wrong order and would by broken by the fix.
> 
> Note: A previous version [1] of the patch contained "Cc: stable" and
> "Fixes:" tags, but they seem to have been accidentally left out from
> the final version.
> 
> [1]: https://lore.kernel.org/all/20250320172654.624657-1-maxbr@linux.ibm.com/
> 
> Thanks,
> Filip Hejsek

But I thought we are reverting it?

-- 
MST

Re: Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

[Filip Hejsek]

On Mon, 2025-10-06 at 06:29 -0400, Michael S. Tsirkin wrote:
> On Thu, Sep 18, 2025 at 01:13:24AM +0200, Filip Hejsek wrote:
> > Hi,
> > 
> > I would like to request backporting 5326ab737a47 ("virtio_console: fix
> > order of fields cols and rows") to all LTS kernels.
> > 
> > I'm working on QEMU patches that add virtio console size support.
> > Without the fix, rows and columns will be swapped.
> > 
> > As far as I know, there are no device implementations that use the
> > wrong order and would by broken by the fix.
> > 
> > Note: A previous version [1] of the patch contained "Cc: stable" and
> > "Fixes:" tags, but they seem to have been accidentally left out from
> > the final version.
> > 
> > [1]: https://lore.kernel.org/all/20250320172654.624657-1-maxbr@linux.ibm.com/
> > 
> > Thanks,
> > Filip Hejsek
> 
> But I thought we are reverting it?

I'm kinda confused by this question, because I thought you already
understood the situation.

I sent this backport request after a discussion with Max in the revert
thread, from which I got the impression that the virtio spec
maintainers were unwilling to change the spec to match the Linux
implementation. That impression might have been wrong though.

When you sent Linus a pull request containing the revert, I realized
that there was no consensus about which side should be fixed (spec or
Linux) and told you that I think it should be reverted only if the spec
is also changed. You then sent a spec change patch [1] to the virtio
mailing list.

I'm not familiar with how decisions about the virtio spec are made, so
I don't know if that change is going to be accepted or not.

[1]: https://lore.kernel.org/virtio-comment/7b939d85ec0b532bae4c16bb927edddcf663bb48.1758212319.git.mst@redhat.com/t/

Best regards,
Filip Hejsek

Re: Backport request for commit 5326ab737a47 ("virtio_console: fix order of fields cols and rows")

[Michael S. Tsirkin]

On Mon, Oct 06, 2025 at 04:15:10PM +0200, Filip Hejsek wrote:
> On Mon, 2025-10-06 at 06:29 -0400, Michael S. Tsirkin wrote:
> > On Thu, Sep 18, 2025 at 01:13:24AM +0200, Filip Hejsek wrote:
> > > Hi,
> > > 
> > > I would like to request backporting 5326ab737a47 ("virtio_console: fix
> > > order of fields cols and rows") to all LTS kernels.
> > > 
> > > I'm working on QEMU patches that add virtio console size support.
> > > Without the fix, rows and columns will be swapped.
> > > 
> > > As far as I know, there are no device implementations that use the
> > > wrong order and would by broken by the fix.
> > > 
> > > Note: A previous version [1] of the patch contained "Cc: stable" and
> > > "Fixes:" tags, but they seem to have been accidentally left out from
> > > the final version.
> > > 
> > > [1]: https://lore.kernel.org/all/20250320172654.624657-1-maxbr@linux.ibm.com/
> > > 
> > > Thanks,
> > > Filip Hejsek
> > 
> > But I thought we are reverting it?
> 
> I'm kinda confused by this question, because I thought you already
> understood the situation.

Yes - I just noticed this backport request stood unanswered and
I thought it's a good idea to make stable maintainers know it's
not yet the time to do the backport.

Sorry if I did it in a confusing way.


> I sent this backport request after a discussion with Max in the revert
> thread, from which I got the impression that the virtio spec
> maintainers were unwilling to change the spec to match the Linux
> implementation. That impression might have been wrong though.
> 
> When you sent Linus a pull request containing the revert, I realized
> that there was no consensus about which side should be fixed (spec or
> Linux) and told you that I think it should be reverted only if the spec
> is also changed. You then sent a spec change patch [1] to the virtio
> mailing list.
> 
> I'm not familiar with how decisions about the virtio spec are made, so
> I don't know if that change is going to be accepted or not.
> 
> [1]: https://lore.kernel.org/virtio-comment/7b939d85ec0b532bae4c16bb927edddcf663bb48.1758212319.git.mst@redhat.com/t/
> 
> Best regards,
> Filip Hejsek