On Wed, Aug 24, 2022, Chang S. Bae wrote: > On 8/24/2022 2:42 PM, Sean Christopherson wrote: > Maybe this is a policy decision. I don't think that > ARCH_REQ_XCOMP_GUEST_PERM goes away with this. Userspace may still use the > arch_prctl() set. But then it makes more sense and consistent to use > ARCH_GET_XCOMP_SUPP in first place, instead of KVM_X86_XCOMP_GUEST_SUPP, no? KVM_X86_XCOMP_GUEST_SUPP is needed so that userspace understands what _KVM_ supports. > > If QEMU wants to assert that it didn't misconfigure itself, it can assert on the > > config in any number of ways, e.g. assert that ARCH_GET_XCOMP_GUEST_PERM is a > > subset of KVM_X86_XCOMP_GUEST_SUPP at the end of kvm_request_xsave_components(). > > Yes, but I guess the new attribute can make it simple. Adding new uAPI and new exports to eliminate one line of userspace code is not a good tradeoff. Am I missing something? This really seems like solution looking for a problem.
