Messages in this thread | | | From | Wei Huang <> | Subject | Re: [PATCH v3 3/4] KVM: SVM: Add support for SVM instruction address check change | Date | Tue, 26 Jan 2021 09:39:17 -0600 |
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On 1/26/21 5:52 AM, Maxim Levitsky wrote: > On Tue, 2021-01-26 at 03:18 -0500, Wei Huang wrote: >> 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@redhat.com> >> Signed-off-by: Bandan Das <bsd@redhat.com> >> Signed-off-by: Wei Huang <wei.huang2@amd.com> >> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> >> --- >> arch/x86/include/asm/cpufeatures.h | 1 + >> arch/x86/kvm/svm/svm.c | 3 +++ >> 2 files changed, 4 insertions(+) >> >> 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 e5ca01e25e89..f9233c79265b 100644 >> --- a/arch/x86/kvm/svm/svm.c >> +++ b/arch/x86/kvm/svm/svm.c >> @@ -1036,6 +1036,9 @@ static __init int svm_hardware_setup(void) >> } >> } >> >> + if (boot_cpu_has(X86_FEATURE_SVME_ADDR_CHK)) >> + svm_gp_erratum_intercept = false; >> + > Again, I would make svm_gp_erratum_intercept a tri-state module param, > and here if it is in 'auto' state do this. >
I will try to craft a param patch and see if it flies...
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