[PATCH v2 3/3] KVM: SVM: Add support for MPK feature on AMD

[Babu Moger]

The Memory Protection Key (MPK) feature provides a way for applications
to impose page-based data access protections (read/write, read-only or
no access), without requiring modification of page tables and subsequent
TLB invalidations when the application changes protection domains.

This feature is already available in Intel platforms. Now enable the
feature on AMD platforms.

AMD documentation for MPK feature is available at "AMD64 Architecture
Programmerâs Manual Volume 2: System Programming, Pub. 24593 Rev. 3.34,
Section 5.6.6 Memory Protection Keys (MPK) Bit". Documentation can be
obtained at the link below.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
 arch/x86/kvm/svm/svm.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 2f379bacbb26..37fb41ad9149 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -818,6 +818,10 @@ static __init void svm_set_cpu_caps(void)
 	if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) ||
 	    boot_cpu_has(X86_FEATURE_AMD_SSBD))
 		kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
+
+	/* PKU is not yet implemented for shadow paging. */
+	if (npt_enabled && boot_cpu_has(X86_FEATURE_OSPKE))
+		kvm_cpu_cap_check_and_set(X86_FEATURE_PKU);
 }
 
 static __init int svm_hardware_setup(void)