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

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Message-ID: <20241203092721.j473dthkbq6wzez7@altlinux.org>
Date: Tue, 3 Dec 2024 12:27:21 +0300
From: Vitaly Chikunov <vt@...linux.org>
To: Marc Zyngier <maz@...nel.org>
Cc: Will Deacon <will@...nel.org>, james.morse@....com,
	linux-arm-kernel@...ts.infradead.org,
	Catalin Marinas <catalin.marinas@....com>,
	linux-kernel@...r.kernel.org, oliver.upton@...ux.dev,
	mark.rutland@....com
Subject: Re: v6.13-rc1: Internal error: Oops - Undefined instruction:
 0000000002000000 [#1] SMP

Marc,

On Tue, Dec 03, 2024 at 01:31:19AM +0300, Vitaly Chikunov wrote:
> 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@...linux.org> 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.
> 
> > 
> > - you get a nastygram in the host log telling you that the guest has
> >   executed something it shouldn't (you'll get the encoding of the
> >   instruction)
> 
> I requested admins of the box for dmesg output since I don't have root
> access myself and nowadays dmesg is not accessible for a user.

This is what they reported:

  kvm [2502822]: Unsupported guest sys_reg access at: ffff80008003e9f0 [000000c5]
                   { Op0( 3), Op1( 0), CRn(10), CRm( 4), Op2( 4), func_read },

Thanks,

> 
> > 
> > Can you confirm these two things?
> 
> Also, I tried to reproduce on another Kunpeng box with slightly
> different HiSilicon CPU (presenting to the system as Cortex-A72) and the
> problem is not reproducible there.
> 
> While things are not resolved, is it possible to workaround the problem
> with some QEMU option, kernel command line, config option, or a patch?
> 
> Thanks,
> 
> > 
> > 	M.
> > 
> > -- 
> > Without deviation from the norm, progress is not possible.