KVM: VMX: Check KVM CPU caps, not just VMX MSR support, for XSAVE enabling

Check KVM CPU capabilities instead of raw VMX support for XSAVES when
determining whether or not XSAVER can/should be exposed to the guest.
Practically speaking, it's nonsensical/impossible for a CPU to support
"enable XSAVES" without XSAVES being supported natively.  The real
motivation for checking kvm_cpu_cap_has() is to allow using the governed
feature's standard check-and-set logic.

Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230815203653.519297-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 159a58c..968401b 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7743,7 +7743,7 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
         * to the guest.  XSAVES depends on CR4.OSXSAVE, and CR4.OSXSAVE can be
         * set if and only if XSAVE is supported.
         */
-       vcpu->arch.xsaves_enabled = cpu_has_vmx_xsaves() &&
+       vcpu->arch.xsaves_enabled = kvm_cpu_cap_has(X86_FEATURE_XSAVES) &&
                                    boot_cpu_has(X86_FEATURE_XSAVE) &&
                                    guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
                                    guest_cpuid_has(vcpu, X86_FEATURE_XSAVES);