On Thu, Dec 12, 2024, Xin Li wrote: > On 10/24/2024 12:18 AM, Chao Gao wrote: > > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > > > index 03f42b218554..bfdd10773136 100644 > > > --- a/arch/x86/kvm/vmx/vmx.c > > > +++ b/arch/x86/kvm/vmx/vmx.c > > > @@ -8009,6 +8009,10 @@ void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) > > > kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_LAM); > > > kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_FRED); > > > > > > + /* Don't allow CR4.FRED=1 before all of FRED KVM support is in place. */ > > > + if (!guest_can_use(vcpu, X86_FEATURE_FRED)) > > > + vcpu->arch.cr4_guest_rsvd_bits |= X86_CR4_FRED; > > > > is this necessary? __kvm_is_valid_cr4() ensures that guests cannot set any bit > > which isn't supported by the hardware. > > > > To account for hardware/KVM caps, I think the following changes will work. This > > will fix all other bits besides X86_CR4_FRED. > > This seems a generic infra improvement, maybe it's better for you to > send it as an individual patch to Sean and the KVM mailing list? Already ahead of y'all :-) (I think, I didn't look closely at this). https://lore.kernel.org/all/20241128013424.4096668-6-seanjc@xxxxxxxxxx
