On Thu, 2023-05-04 at 09:20 +0800, Yang, Weijiang wrote: > > On 5/4/2023 1:07 AM, Edgecombe, Rick P wrote: > > On Fri, 2023-04-21 at 09:46 -0400, Yang Weijiang wrote: > > > + > > > + incpt = !is_cet_state_supported(vcpu, > > > XFEATURE_MASK_CET_KERNEL); > > > + incpt |= !guest_cpuid_has(vcpu, X86_FEATURE_SHSTK); > > > + > > > + vmx_set_intercept_for_msr(vcpu, MSR_IA32_INT_SSP_TAB, > > > MSR_TYPE_RW, incpt); > > > + vmx_set_intercept_for_msr(vcpu, MSR_IA32_PL0_SSP, > > > MSR_TYPE_RW, incpt); > > > + vmx_set_intercept_for_msr(vcpu, MSR_IA32_PL1_SSP, > > > MSR_TYPE_RW, incpt); > > > + vmx_set_intercept_for_msr(vcpu, MSR_IA32_PL2_SSP, > > > MSR_TYPE_RW, incpt); > > > } > > Why is this tied to XFEATURE_MASK_CET_KERNEL? I don't know how the > > SVM > > side works, but the host kernel doesn't use this xfeature. Just not > > clear on what the intention is. Why not use > > kvm_cet_kernel_shstk_supported() again? > > I don't know how SVM supports supervisor SHSTK either, here just > follows > the spec. What aspect of the spec is this? > > to add the dependency check. Maybe you're right, I need to use > kvm_cet_kernel_shstk_supported() > > in my patch set and leave the work to SVM enabling patches. I'll > change > it, thanks! Oh, I see the the SVM patch [0] is adding XFEATURE_MASK_CET_KERNEL to kvm_caps.supported_xss as long as kvm_cpu_cap_has(X86_FEATURE_SHSTK). And it does not look to be checking XSS host support like how kvm_caps.supported_xss is set in your patch. It should depend on host support, right? Is that the intent of kvm_caps.supported_xss? Separate from all that, the code above is in VMX, so not sure how it affects SVM in any case. I might be confused here. The code just looked suspicious. [0] https://lore.kernel.org/kvm/20221012203910.204793-8-john.allen@xxxxxxx/
