[Bug] virtio-gpu broken with qemu/kvm on arm64 on kernel 5.5+

[Gurchetan Singh]

On Fri, Feb 21, 2020 at 10:41 AM Chia-I Wu <olvaffe at gmail.com> wrote:
>
> On Fri, Feb 21, 2020 at 2:06 AM Guillaume Gardet
> <Guillaume.Gardet at arm.com> wrote:
> >
> > Hi,
> >
> > > -----Original Message-----
> > > From: Chia-I Wu <olvaffe at gmail.com>
> > > Sent: 20 February 2020 19:41
> > > To: Guillaume Gardet <Guillaume.Gardet at arm.com>
> > > Cc: dri-devel at lists.freedesktop.org; Gerd Hoffmann <kraxel at redhat.com>;
> > > Daniel Vetter <daniel.vetter at ffwll.ch>; Catalin Marinas
> > > <Catalin.Marinas at arm.com>; nd <nd at arm.com>
> > > Subject: Re: [Bug] virtio-gpu broken with qemu/kvm on arm64 on kernel 5.5+
> > >
> > > On Thu, Feb 20, 2020 at 4:44 AM Guillaume Gardet <Guillaume.Gardet at arm.com>
> > > wrote:
> > > >
> > > > Hi,
> > > >
> > > > With (guest) kernel 5.5+ with qemu/kvm on arm64, I get lots of display
> > > corruptions leading to this kind of screen:
> > > > https://openqa.opensuse.org/tests/1174521#step/yast2_i/24
> > > Looking at the screenshot, it seems cacheline-related?
> >
> > It could be.
> >
> > >
> > > There was a change of memory type
> > >
> > >   https://lists.freedesktop.org/archives/dri-devel/2019-August/233456.html
> > >
> > > While the guest memory type is ignored on Intel, it is honored on ARM.
> > > This attempt to fix it
> > >
> > >   https://lists.freedesktop.org/archives/dri-devel/2019-December/248271.html
> > >
> > > does not seem to land.
> >
> > I applied this patch on top of 5.5.4, but it does not fix the problem.
> > Maybe more similar changes are required?
> The patch looks legit.  Maybe the memory type is not the root cause?

Perhaps try the entire series?

https://patchwork.kernel.org/cover/11300619/