[PATCH 3.18 063/150] kvm: x86: mask out XSAVES

Greg Kroah-Hartman
2015-01-14T08:36:50Z

From: Paolo Bonzini <pbonzini@redhat.com>

commit b65d6e17fe2239c9b2051727903955d922083fbf upstream.

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

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kvm/cpuid.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -319,6 +319,10 @@ static inline int __do_cpuid_ent(struct
F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
F(ADX) | F(SMAP);

+ /* 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();

@@ -455,13 +459,18 @@ static inline int __do_cpuid_ent(struct
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;