Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > On 27/01/20 16:38, Vitaly Kuznetsov wrote: >>>> If there are no objections and if we still think it would be beneficial >>>> to minimize the list of controls we filter out (and not go with the full >>>> set like my RFC suggests), I'll prepare v2. (v1, actually, this was RFC). >>> One last idea, can we keep the MSR filtering as is and add the hack in >>> vmx_restore_control_msr()? That way the (userspace) host and guest see >>> the same values when reading the affected MSRs, and eVMCS wouldn't need >>> it's own hook to do consistency checks. >> Yes but (if I'm not mistaken) we'll have then to keep the filtering we >> currently do in nested_enable_evmcs(): if userspace doesn't do >> KVM_SET_MSR for VMX MSRs (QEMU<4.2) then the filtering in >> vmx_restore_control_msr() won't happen and the guest will see the >> unfiltered set of controls... >> > > Indeed. The place you used in the RFC is the best we can do, I am afraid. > In case we decide to filter out the full set of unsupported stuff there's basically nothing to change, feel free to just treat the RFC as non-RFC :-) (and personally, I'd prefer to keep the 'full set' in the filter as it is less fragile; the 'short list' I came up with is the result of my experiments on one hardware host only and I'm not sure what may make Hyper-V behave differently). I can re-submit, of course, if needed. -- Vitaly
