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Subject[CFT PATCH 1/2] kvm: x86: mask out XSAVES
Date
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
Cc: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/cpuid.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 20d83217fb1d..a4f5ac46226c 100644
--- 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;
--
1.8.3.1



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