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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2018-04-25 22:04:25 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-22 18:54:02 +0200
commit97224b3da69810155b44f173cc8959eea565a98d (patch)
tree8216eadca1d1fd01fc296587d0996f773cbf1fed
parent716bfae3b3f40de8c0a6ae83f199d96fd152b3cc (diff)
x86/KVM/VMX: Expose SPEC_CTRL Bit(2) to the guest
commit da39556f66f5cfe8f9c989206974f1cb16ca5d7c upstream Expose the CPUID.7.EDX[31] bit to the guest, and also guard against various combinations of SPEC_CTRL MSR values. The handling of the MSR (to take into account the host value of SPEC_CTRL Bit(2)) is taken care of in patch: KVM/SVM/VMX/x86/spectre_v2: Support the combination of guest and host IBRS Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kvm/cpuid.c2
-rw-r--r--arch/x86/kvm/vmx.c8
2 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 4f544f2a7b06..69cdad1df3f2 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -394,7 +394,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* cpuid 7.0.edx*/
const u32 kvm_cpuid_7_0_edx_x86_features =
- F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
+ F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) | F(RDS) |
F(ARCH_CAPABILITIES);
/* all calls to cpuid_count() should be made on the same cpu */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 208b431244c1..7a00b5d3c645 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3294,7 +3294,8 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_SPEC_CTRL:
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_IBRS) &&
- !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
+ !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL) &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_RDS))
return 1;
msr_info->data = to_vmx(vcpu)->spec_ctrl;
@@ -3415,11 +3416,12 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_SPEC_CTRL:
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_IBRS) &&
- !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
+ !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL) &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_RDS))
return 1;
/* The STIBP bit doesn't fault even if it's not advertised */
- if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP))
+ if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP | SPEC_CTRL_RDS))
return 1;
vmx->spec_ctrl = data;