[PATCH v4 3/3] KVM: x86: Enable Intel MPX for guest

[Liu Jinsong]

This patch enable Intel MPX feature to guest.

Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
Signed-off-by: Liu Jinsong <jinsong.liu@xxxxxxxxx>
---
 arch/x86/kvm/cpuid.c |    2 +-
 arch/x86/kvm/x86.c   |    6 ++++++
 arch/x86/kvm/x86.h   |    3 ++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b241325..b377d83 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -303,7 +303,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 	/* cpuid 7.0.ebx */
 	const u32 kvm_supported_word9_x86_features =
 		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
-		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | F(RDSEED) |
+		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | F(MPX) | F(RDSEED) |
 		F(ADX);
 
 	/* all calls to cpuid_count() should be made on the same cpu */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 89e4e27..3570e71 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -599,6 +599,9 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 	u64 old_xcr0 = vcpu->arch.xcr0;
 	u64 valid_bits;
 
+	if (!kvm_x86_ops->mpx_supported || !kvm_x86_ops->mpx_supported())
+		xcr0 &= ~(XSTATE_BNDREGS | XSTATE_BNDCSR);
+
 	/* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now  */
 	if (index != XCR_XFEATURE_ENABLED_MASK)
 		return 1;
@@ -616,6 +619,9 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 	if (xcr0 & ~valid_bits)
 		return 1;
 
+	if ((!(xcr0 & XSTATE_BNDREGS)) != (!(xcr0 & XSTATE_BNDCSR)))
+		return 1;
+
 	kvm_put_guest_xcr0(vcpu);
 	vcpu->arch.xcr0 = xcr0;
 
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 8da5823..392ecbf 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -122,7 +122,8 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
 	gva_t addr, void *val, unsigned int bytes,
 	struct x86_exception *exception);
 
-#define KVM_SUPPORTED_XCR0	(XSTATE_FP | XSTATE_SSE | XSTATE_YMM)
+#define KVM_SUPPORTED_XCR0     (XSTATE_FP | XSTATE_SSE | XSTATE_YMM \
+				| XSTATE_BNDREGS | XSTATE_BNDCSR)
 extern u64 host_xcr0;
 
 extern unsigned int min_timer_period_us;
-- 
1.7.1
--
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