> From: Paolo Bonzini > Sent: Wednesday, December 15, 2021 6:41 PM > > There's also another important thing that hasn't been mentioned so far: > KVM_GET_SUPPORTED_CPUID should _not_ include the dynamic bits in > CPUID[0xD] if they have not been requested with prctl. It's okay to > return the AMX bit, but not the bit in CPUID[0xD]. There is no vcpu in this ioctl, thus we cannot check vcpu->arch.guest_fpu.perm. This then requires exposing xstate_get_guest_group_perm() to KVM. Thomas, are you OK with this change given Paolo's ask? v1 included this change but it was not necessary at the moment: https://lore.kernel.org/lkml/87lf0ot50q.ffs@tglx/ and Paolo, do we want to document that prctl() must be done before calling KVM_GET_SUPPORTED_CPUID? If yes, where is the proper location? Thanks Kevin
