On Tue, May 4, 2021 at 2:57 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 04/05/21 23:53, Sean Christopherson wrote: > >> Does the right thing happen here if the vCPU is in guest mode when > >> userspace decides to toggle the CPUID.80000001H:EDX.RDTSCP bit on or > >> off? > > I hate our terminology. By "guest mode", do you mean running the vCPU, or do > > you specifically mean running in L2? > > > > Guest mode should mean L2. > > (I wonder if we should have a capability that says "KVM_SET_CPUID2 can > only be called prior to KVM_RUN"). It would certainly make it easier to reason about potential security issues.