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 <bsd@xxxxxxxxxx> Signed-off-by: Bandan Das <bsd@xxxxxxxxxx> Signed-off-by: Wei Huang <wei.huang2@xxxxxxx> --- 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
