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kvm: x86: Guest BNDCFGS requires guest MPX support

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commit 4439af9f911ae0243ffe4e2dfc12bace49605d8b upstream.

The BNDCFGS MSR should only be exposed to the guest if the guest
supports MPX. (cf. the TSC_AUX MSR and RDTSCP.)

Fixes: 0dd376e709975779 ("KVM: x86: add MSR_IA32_BNDCFGS to msrs_to_save")
Change-Id: I3ad7c01bda616715137ceac878f3fa7e66b6b387
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jim Mattson 2017-05-24 10:49:25 -07:00 committed by Greg Kroah-Hartman
parent bf7c215356
commit fab777e70c
2 changed files with 10 additions and 2 deletions
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8
arch/x86/kvm/cpuid.h
View File

@ -144,6 +144,14 @@ static inline bool guest_cpuid_has_rtm(struct kvm_vcpu *vcpu)
return best && (best->ebx & bit(X86_FEATURE_RTM));
}
static inline bool guest_cpuid_has_mpx(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 7, 0);
return best && (best->ebx & bit(X86_FEATURE_MPX));
}
static inline bool guest_cpuid_has_rdtscp(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;

4
arch/x86/kvm/vmx.c
View File

@ -2987,7 +2987,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
msr_info->data = vmcs_readl(GUEST_SYSENTER_ESP);
break;
case MSR_IA32_BNDCFGS:
if (!kvm_mpx_supported())
if (!kvm_mpx_supported() || !guest_cpuid_has_mpx(vcpu))
return 1;
msr_info->data = vmcs_read64(GUEST_BNDCFGS);
break;
@ -3069,7 +3069,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
vmcs_writel(GUEST_SYSENTER_ESP, data);
break;
case MSR_IA32_BNDCFGS:
if (!kvm_mpx_supported())
if (!kvm_mpx_supported() || !guest_cpuid_has_mpx(vcpu))
return 1;
vmcs_write64(GUEST_BNDCFGS, data);
break;