On Wed, 2023-05-24 at 15:53 +0000, John Allen wrote: > If the CPU supports CET, add CET XSAVES feature bits to the > supported_xss mask. > > Signed-off-by: John Allen <john.allen@xxxxxxx> > --- > v2: > - Remove curly braces around if statement > --- > arch/x86/kvm/svm/svm.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 6afd2c44fdb6..cee496bee0a9 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -5070,6 +5070,10 @@ static __init void svm_set_cpu_caps(void) > boot_cpu_has(X86_FEATURE_AMD_SSBD)) > kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD); > > + if (kvm_cpu_cap_has(X86_FEATURE_SHSTK)) > + kvm_caps.supported_xss |= XFEATURE_MASK_CET_USER | > + XFEATURE_MASK_CET_KERNEL; > + Is setting XFEATURE_MASK_CET_KERNEL here ok? The host kernel will not support XFEATURE_MASK_CET_KERNEL. I guess after this there is a small window of time where host IA32_XSS could have non-host supported supervisor state. Sort of separately, how does SVM work with respect to saving and restoring guest supervisor CET state (I mean the CET_S stuff)? I'm not sure there is any problem, but just wondering how it all works. Thanks.
