4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
commit c469268cd523245cc58255f6696e0c295485cb0b upstream.
If the host has protection keys disabled, we cannot read and write the
guest PKRU---RDPKRU and WRPKRU fail with #GP(0) if CR4.PKE=0. Block
the PKU cpuid bit in that case.
This ensures that guest_CR4.PKE=1 implies host_CR4.PKE=1.
Fixes: 1be0e61c1f255faaeab04a390e00c8b9b9042870
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -456,7 +456,7 @@ static inline int __do_cpuid_ent(struct
entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
cpuid_mask(&entry->ecx, CPUID_7_ECX);
/* PKU is not yet implemented for shadow paging. */
- if (!tdp_enabled)
+ if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
entry->ecx &= ~F(PKU);
} else {
entry->ebx = 0;