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authorPaolo Bonzini <pbonzini@redhat.com>2013-10-17 16:50:46 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2013-10-31 11:30:46 +0100
commit46c34cb059d519601fb567b55cf45c300fea2928 (patch)
tree7714d9f5073951ce554a417a0fb246ed5d424c39 /arch/x86
parente0f0bbc527f6e9c0261f1d16b2a0b47612b7f235 (diff)
downloadop-kernel-dev-46c34cb059d519601fb567b55cf45c300fea2928.zip
op-kernel-dev-46c34cb059d519601fb567b55cf45c300fea2928.tar.gz
KVM: x86: fix KVM_SET_XCRS for CPUs that do not support XSAVE
The KVM_SET_XCRS ioctl must accept anything that KVM_GET_XCRS could return. XCR0's bit 0 is always 1 in real processors with XSAVE, and KVM_GET_XCRS will always leave bit 0 set even if the emulated processor does not have XSAVE. So, KVM_SET_XCRS must ignore that bit when checking for attempts to enable unsupported save states. Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/x86.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ec35d09..2961549 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -577,6 +577,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
u64 xcr0;
+ u64 valid_bits;
/* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now */
if (index != XCR_XFEATURE_ENABLED_MASK)
@@ -586,8 +587,16 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
return 1;
if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
return 1;
- if (xcr0 & ~vcpu->arch.guest_supported_xcr0)
+
+ /*
+ * Do not allow the guest to set bits that we do not support
+ * saving. However, xcr0 bit 0 is always set, even if the
+ * emulated CPU does not support XSAVE (see fx_init).
+ */
+ valid_bits = vcpu->arch.guest_supported_xcr0 | XSTATE_FP;
+ if (xcr0 & ~valid_bits)
return 1;
+
kvm_put_guest_xcr0(vcpu);
vcpu->arch.xcr0 = xcr0;
return 0;
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