Re: 5.18 vmwgfx seems to break booting VirtualBox VMs

[Zack Rusin <zackr@vmware.com>]

On Tue, 2022-05-10 at 15:49 +0200, Thorsten Leemhuis wrote:
> On 10.05.22 15:30, Zack Rusin wrote:
> > On Tue, 2022-05-10 at 14:44 +0200, Thorsten Leemhuis wrote:
> > > On 10.05.22 14:26, Zack Rusin wrote:
> > > > > On May 10, 2022, at 7:06 AM, Thorsten Leemhuis
> > > > > <regressions@leemhuis.info> wrote:
> > > > > On 10.05.22 02:12, Zack Rusin wrote:
> > > > > > > On May 9, 2022, at 6:57 AM, Hans de Goede
> > > > > > > <hdegoede@redhat.com>
> > > > > > > wrote: On 4/11/22 16:24, Zack Rusin wrote:
> > > > > > > > On Mon, 2022-04-11 at 10:52 +0200, Hans de Goede wrote:
> > > > > > > > > 
> > > > > > > > > Fedora has received a bug report here:
> > > > > > > > > 
> > > > > > > > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.redhat.com%2Fshow_bug.cgi%3Fid%3D2072556&amp;data=05%7C01%7Czackr%40vmware.com%7C1896f8be197a445e6a9608da328bec17%7Cb39138ca3cee4b4aa4d6cd83d9dd62f0%7C0%7C0%7C637877873804355302%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=Yo54IWpXj9XBu68FLO0IxG61oSCKkUnVD5nXA8sW1g8%3D&amp;reserved=0
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > That Fedora rawhide VMs no longer boot under the VirtualBox
> > > > > > > > > hypervisor after the VM has been updated to a 5.18-
> > > > > > > > > rc#
> > > > > > > > > kernel.
> > > > > > > > > 
> > > > > > > > > Switching the emulated GPU from vmwaregfx to
> > > > > > > > > VirtualBoxSVGA
> > > > > > > > > fixes this, so this seems to be a vmwgfx driver
> > > > > > > > > regression.
> > > > > > > > > 
> > > > > > > > > Note I've not investigated/reproduced this myself due
> > > > > > > > > to
> > > > > > > > > -ENOTIME.
> > > > > > > > 
> > > > > > > > Thanks for letting us know. Unfortunately we do not
> > > > > > > > support
> > > > > > > > vmwgfx on VirtualBox. I'd be happy to review patches
> > > > > > > > related to
> > > > > > > > this, but it's very unlikely we'd have to time to look
> > > > > > > > at
> > > > > > > > this
> > > > > > > > ourselves.
> > > > > > > 
> > > > > > > I somewhat understand where you are coming from, but this
> > > > > > > is
> > > > > > > not 
> > > > > > > how the kernels "no regressions" policy works.
> > > > > 
> > > > > Hans, many thx for writing your mail, I once intended to
> > > > > write
> > > > > something
> > > > > similar, but then forgot about it. :-/
> > > > > 
> > > > > > > For the end user a regression is a regression and as
> > > > > > > maintainers we
> > > > > > > are supposed to make sure any regressions noticed are
> > > > > > > fixed
> > > > > > > before
> > > > > > > a new kernel hits end user's systems.
> > > > > > 
> > > > > > I think there’s a misunderstanding here - the vmwgfx driver
> > > > > > never
> > > > > > supported VirtualBox. VirtualBox implementation of the svga
> > > > > > device
> > > > > > lacks a bunch of features,
> > > > > 
> > > > > Which from the kernel's point of view is irrelevant. If the
> > > > > Linux
> > > > > kernel's vmwgfx driver ever supported the VirtualBox
> > > > > implementation then
> > > > > things shouldn't regress with later versions.
> > > > It never did. vmwgfx is just a driver for VMware's SVGA device,
> > > > it
> > > > never supported anything else. 
> > > 
> > > Now I'm curious and would like to understand the issue properly,
> > > if
> > > you
> > > have a minute. :-D
> > > 
> > > I didn't mean "supported" as in "officially supported", I meant
> > > as in
> > > "it ran (as in automatically bonded) on VirtualBox in one of the
> > > modes
> > > one could configure in VirtualBox for virtual GPU". And the
> > > latter is
> > > the case here afaics, or isn't it?
> > 
> > I wouldn't know that. But if the claim is that anyone lying about
> > the
> > type of device they are can hijack development then we'll need
> > Linus to
> > clarify that,
> 
> Feel free to ask, I doubt that will work out, but yes, in the end
> it's
> Linus decision.
> 
> > i.e. if I create a PCI device that identifies itself as a
> > random AMD GPU
> 
> That's not the case and thus a misleading example afaics.

No, that's exactly the case. VirtualBox lies in its PCI ID and claims
that it's a VMware SVGA when it clearly isn't.

z