On Tue, Aug 30, 2022 at 03:37:06PM +0200, Vitaly Kuznetsov wrote: > Updated Hyper-V Enlightened VMCS specification lists several new > fields for the following features: > > - PerfGlobalCtrl > - EnclsExitingBitmap > - Tsc Scaling > - GuestLbrCtl > - CET > - SSP > > Update the definition. > > Note, the updated spec also provides an additional CPUID feature flag, > CPUIDD.0x4000000A.EBX BIT(0), for PerfGlobalCtrl to workaround a Windows > 11 quirk. Despite what the TLFS says: > > Indicates support for the GuestPerfGlobalCtrl and HostPerfGlobalCtrl > fields in the enlightened VMCS. > > guests can safely use the fields if they are enumerated in the > architectural VMX MSRs. I.e. KVM-on-HyperV doesn't need to check the > CPUID bit, but KVM-as-HyperV must ensure the bit is set if PerfGlobalCtrl > fields are exposed to L1. > > https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/tlfs > > Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > [sean: tweak CPUID name to make it PerfGlobalCtrl only] > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Acked-by: Wei Liu <wei.liu@xxxxxxxxxx>
