On Mon, Nov 9, 2020 at 2:09 PM Luck, Tony <tony.luck@xxxxxxxxx> wrote: > > What does KVM do with model specific MSRs? "Model specific model-specific registers?" :-) KVM only implements a small subset of MSRs. By default, any access to the rest raises #GP. > Looks like you let the guest believe it was running on one of Sandy Bridge, Ivy Bridge, Haswell (Xeon). > > So, the core MCE code tried to enable extended error reporting. > > If there is a mode to have KVM let the guest think that it read/wrote MSR 0x17F, > but actually, doesn't do it ... that would seem to be a reasonable thing to do here. There is an 'ignore_msrs' module parameter, to sink writes and return zero on reads for unknown MSRs, but I don't think it's commonly used. I thought Linux had long ago gone the route of turning rdmsr/wrmsr into rdmsr_safe/wrmsr_safe, so that the guest would ignore the #GPs on writes and return zero to the caller for #GPs on reads.