Re: [qemu64,+smep,+smap] WARNING: CPU: 1 PID: 0 at arch/x86/kernel/cpu/amd.c:220 init_amd()

From: H. Peter Anvin
Date: Fri Mar 07 2014 - 16:01:45 EST


On 03/07/2014 11:10 AM, Dave Jones wrote:
> On Fri, Mar 07, 2014 at 10:56:11AM -0800, H. Peter Anvin wrote:
> > On 03/06/2014 09:50 PM, Fengguang Wu wrote:
> > >>
> > >> Unfortunately these things are hard to fix in Qemu.
> > >
> > > OK. As an alternative, is it possible to pass one of the below CPUID flags in
> > > the Qemu command line, so as to quiet the warning?
> > >
> >
> > I don't see the AMD SMP CPUID flag in there.
> >
> > Boris, could you help? The problem is that "qemu -cpu
> > qemu64,+smep,+smap" identifies as an AMD CPU which triggers a
> > warning/taint because the SMP flag isn't set.
>
> qemu64 triggers this ? That spew comes from amd_k7_smp_check()
> which should only run on family 6, which was all 32bit.
>

[ 0.152749] smpboot: CPU0: AMD QEMU Virtual CPU version 1.6.0 (fam:
06, model: 02, stepping: 03)

Seems they are using a really odd CPUID combination, then.

-hpa

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