On Tue, 15 Aug 2017, Mike Larkin wrote:
> On Tue, Aug 15, 2017 at 08:46:59AM -0700, Mike Larkin wrote:
> > On Tue, Aug 15, 2017 at 05:39:29PM +0200, Stefan Fritsch wrote:
> > > I have got a report that openbsd panics on boot with qemu -cpu Opteron_G3
> > > (but Opteron_G2 works).
> > >
> > > kernel: protection fault trap, code=0
> > > Stopped at amd64_errata_setmsr+0x14: rdmsr
> > > ddb{0}> >> OpenBSD/amd64 BOOT 3.33
> > > boot>
> > >
> > > Qemu does not implement all the secret errata MSRs. Does it make sense to
> > > simply skip all errata processing if we detect a hypervisor?
> > >
> > >
> > > diff --git a/sys/arch/amd64/amd64/identcpu.c
> > > b/sys/arch/amd64/amd64/identcpu.c
> > > index a448b885ba7..371c0c8ff48 100644
> > > --- a/sys/arch/amd64/amd64/identcpu.c
> > > +++ b/sys/arch/amd64/amd64/identcpu.c
> > > @@ -708,7 +708,7 @@ identifycpu(struct cpu_info *ci)
> > > }
> > > #endif
> > >
> > > - if (!strcmp(cpu_vendor, "AuthenticAMD"))
> > > + if (!strcmp(cpu_vendor, "AuthenticAMD") && !ISSET(cpu_ecxfeature,
> > > CPUIDECX_HV))
> > > amd64_errata(ci);
> > >
> > > if (CPU_IS_PRIMARY(ci) && !strcmp(cpu_vendor, "CentaurHauls")) {
> > >
> >
> > I think this is an upstream bug. If they claim to emulate a G3 Opteron, they
> > should be faithfully emulating it.
True. But I could imagine that this is difficult if there is no hint that
a specific MSR exists until AMD releases an erratum that uses it as a
work-around. At the very least, there will be old qemu/kvm versions around
that don't implement it, yet. Not sure if that is the problem, here,
though.
> Also, is this only an error in TCG?
The panic above is from qemu+kvm+linux. Not sure what happens with TCG.
