Re: v6.13-rc1: Internal error: Oops - Undefined instruction: 0000000002000000 [#1] SMP

From: Oliver Upton
Date: Mon Dec 02 2024 - 20:20:16 EST


On Tue, Dec 03, 2024 at 01:31:19AM +0300, Vitaly Chikunov wrote:
> Marc,
>
> On Mon, Dec 02, 2024 at 04:07:03PM +0000, Marc Zyngier wrote:
> > On Mon, 02 Dec 2024 15:59:40 +0000,
> > Vitaly Chikunov <vt@xxxxxxxxxxxx> wrote:
> > >
> > > Marc,
> > >
> > > On Mon, Dec 02, 2024 at 03:53:59PM +0000, Marc Zyngier wrote:
> > > >
> > > > What the log doesn't say is what the host is. Is it 6.13-rc1 as well?
> > >
> > > No, host is 6.6.60.
> >
> > Right. I wouldn't be surprised if:
> >
> > - this v6.6 kernel doesn't hide the MPAM feature as it should (and
> > that's proably something we should backport)
>
> How to confirm this? Currently I cannot find any (case-insensitive)
> "MPAM" files in /sys, nor mpam string in /proc/cpuinfo, nor MPAM strings
> in `strace -v` (as it decodes some KVM ioctls) of qemu process.

If you can attach to the QEMU gdbstub of the VM, info registers will
dump ~everything.

If the value of ID_AA64PFR0_EL1.MPAM (bits 43:40) is nonzero then the
host KVM is erroneously advertising MPAM to the guest.

--
Thanks,
Oliver