New AMD CPUs have a change that checks VMEXIT intercept on special SVM
instructions before checking their EAX against reserved memory region.
This change is indicated by CPUID_0x8000000A_EDX[28]. If it is 1, #VMEXIT
is triggered before #GP. KVM doesn't need to intercept and emulate #GP
faults as #GP is supposed to be triggered.
Co-developed-by: Bandan Das <b...@redhat.com>
Signed-off-by: Bandan Das <b...@redhat.com>
Signed-off-by: Wei Huang <wei.hua...@amd.com>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kvm/svm/svm.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/cpufeatures.h
b/arch/x86/include/asm/cpufeatures.h
index 84b887825f12..ea89d6fdd79a 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -337,6 +337,7 @@
#define X86_FEATURE_AVIC (15*32+13) /* Virtual Interrupt
Controller */
#define X86_FEATURE_V_VMSAVE_VMLOAD (15*32+15) /* Virtual VMSAVE VMLOAD */
#define X86_FEATURE_VGIF (15*32+16) /* Virtual GIF */
+#define X86_FEATURE_SVME_ADDR_CHK (15*32+28) /* "" SVME addr check */
/* Intel-defined CPU features, CPUID level 0x00000007:0 (ECX), word 16 */
#define X86_FEATURE_AVX512VBMI (16*32+ 1) /* AVX512 Vector Bit
Manipulation instructions*/
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 6ed523cab068..2a12870ac71a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -313,7 +313,8 @@ int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
svm->vmcb->save.efer = efer | EFER_SVME;
vmcb_mark_dirty(svm->vmcb, VMCB_CR);
/* Enable #GP interception for SVM instructions */
- set_exception_intercept(svm, GP_VECTOR);
+ if (!kvm_cpu_cap_has(X86_FEATURE_SVME_ADDR_CHK))
+ set_exception_intercept(svm, GP_VECTOR);
return 0;
}
@@ -933,6 +934,9 @@ static __init void svm_set_cpu_caps(void)
boot_cpu_has(X86_FEATURE_AMD_SSBD))
kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
+ if (boot_cpu_has(X86_FEATURE_SVME_ADDR_CHK))
+ kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);
+
/* Enable INVPCID feature */
kvm_cpu_cap_check_and_set(X86_FEATURE_INVPCID);
}
--
2.27.0
