On Tue, 2020-05-26 at 18:21 -0700, Sean Christopherson wrote: > On Sat, May 23, 2020 at 07:14:55PM +0300, Maxim Levitsky wrote: > > This msr is only available when the host supports WAITPKG feature. > > > > This breaks a nested guest, if the L1 hypervisor is set to ignore > > unknown msrs, because the only other safety check that the > > kernel does is that it attempts to read the msr and > > rejects it if it gets an exception. > > > > Fixes: 6e3ba4abce KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL > > Same comments on the line wraps and Fixes tag. I rewrote the commit message and I hope that the new version is better. I fixed the 'fixes' message as well. > > For the code: > > Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Thank you! Best regards, Maxim Levitsky > > > Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> > > --- > > arch/x86/kvm/x86.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index b226fb8abe41b..4752293312947 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -5316,6 +5316,10 @@ static void kvm_init_msr_list(void) > > min(INTEL_PMC_MAX_GENERIC, > > x86_pmu.num_counters_gp)) > > continue; > > break; > > + case MSR_IA32_UMWAIT_CONTROL: > > + if (!kvm_cpu_cap_has(X86_FEATURE_WAITPKG)) > > + continue; > > + break; > > default: > > break; > > } > > -- > > 2.26.2 > >
