KVM: X86: Extend CPUID range to include new leaf

This CPUID leaf provides the memory encryption support information on
AMD Platform. Its complete description is available in APM volume 2,
Section 15.34

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NBrijesh Singh <brijesh.singh@amd.com>

arch/x86/kvm/cpuid.c

@@ -604,7 +604,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		entry->edx = 0;
 		break;
 	case 0x80000000:
-		entry->eax = min(entry->eax, 0x8000001a);
+		entry->eax = min(entry->eax, 0x8000001f);
 		break;
 	case 0x80000001:
 		entry->edx &= kvm_cpuid_8000_0001_edx_x86_features;

arch/x86/kvm/svm.c

@@ -5170,6 +5170,12 @@ static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
 			entry->edx |= SVM_FEATURE_NPT;
 
 		break;
+	case 0x8000001F:
+		/* Support memory encryption cpuid if host supports it */
+		if (boot_cpu_has(X86_FEATURE_SEV))
+			cpuid(0x8000001f, &entry->eax, &entry->ebx,
+				&entry->ecx, &entry->edx);
+
 	}
 }