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kvm/svm: PKU not currently supported

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Current SVM implementation does not have support for handling PKU. Guests
running on a host with future AMD cpus that support the feature will read
garbage from the PKRU register and will hit segmentation faults on boot as
memory is getting marked as protected that should not be. Ensure that cpuid
from SVM does not advertise the feature.

Signed-off-by: John Allen <john.allen@amd.com>
Cc: stable@vger.kernel.org
Fixes: 0556cbdc2f ("x86/pkeys: Don't check if PKRU is zero before writing it")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
John Allen
2019-12-19 14:17:59 -06:00
committed by Paolo Bonzini
parent 8bd826d629
commit a47970ed74
5 changed files with 16 additions and 1 deletions
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4
arch/x86/kvm/cpuid.c
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@@ -353,6 +353,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index)
unsigned f_umip = kvm_x86_ops->umip_emulated() ? F(UMIP) : 0;
unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
unsigned f_la57;
unsigned f_pku = kvm_x86_ops->pku_supported() ? F(PKU) : 0;
/* cpuid 7.0.ebx */
const u32 kvm_cpuid_7_0_ebx_x86_features =
@@ -364,7 +365,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index)
/* cpuid 7.0.ecx*/
const u32 kvm_cpuid_7_0_ecx_x86_features =
F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) |
F(AVX512VBMI) | F(LA57) | 0 /*PKU*/ | 0 /*OSPKE*/ | F(RDPID) |
F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/;
@@ -393,6 +394,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index)
/* Set LA57 based on hardware capability. */
entry->ecx |= f_la57;
entry->ecx |= f_umip;
entry->ecx |= f_pku;
/* PKU is not yet implemented for shadow paging. */
if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
entry->ecx &= ~F(PKU);