kvm: x86: mask out XSAVES

This feature is not supported inside KVM guests yet, because we do not emulate
MSR_IA32_XSS.  Mask it out.

Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 20d8321..a4f5ac4 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -320,6 +320,10 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                F(ADX) | F(SMAP) | F(AVX512F) | F(AVX512PF) | F(AVX512ER) |
                F(AVX512CD);
 
+       /* cpuid 0xD.1.eax */
+       const u32 kvm_supported_word10_x86_features =
+               F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1);
+
        /* all calls to cpuid_count() should be made on the same cpu */
        get_cpu();
 
@@ -456,13 +460,18 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                entry->eax &= supported;
                entry->edx &= supported >> 32;
                entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+               if (!supported)
+                       break;
+
                for (idx = 1, i = 1; idx < 64; ++idx) {
                        u64 mask = ((u64)1 << idx);
                        if (*nent >= maxnent)
                                goto out;
 
                        do_cpuid_1_ent(&entry[i], function, idx);
-                       if (entry[i].eax == 0 || !(supported & mask))
+                       if (idx == 1)
+                               entry[i].eax &= kvm_supported_word10_x86_features;
+                       else if (entry[i].eax == 0 || !(supported & mask))
                                continue;
                        entry[i].flags |=
                               KVM_CPUID_FLAG_SIGNIFCANT_INDEX;