1 files changed, 33 insertions, 11 deletions

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index bfc0bfcb2bc6..f2f2be5d1141 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -376,6 +376,7 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 
 	kvm_update_pv_runtime(vcpu);
 
+	vcpu->arch.is_amd_compatible = guest_cpuid_is_amd_or_hygon(vcpu);
 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
 	vcpu->arch.reserved_gpa_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
 
@@ -771,7 +772,7 @@ void kvm_set_cpu_caps(void)
 	kvm_cpu_cap_mask(CPUID_8000_000A_EDX, 0);
 
 	kvm_cpu_cap_mask(CPUID_8000_001F_EAX,
-		0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) |
+		0 /* SME */ | 0 /* SEV */ | 0 /* VM_PAGE_FLUSH */ | 0 /* SEV_ES */ |
 		F(SME_COHERENT));
 
 	kvm_cpu_cap_mask(CPUID_8000_0021_EAX,
@@ -1231,9 +1232,22 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = entry->ebx = entry->ecx = 0;
 		break;
 	case 0x80000008: {
-		unsigned g_phys_as = (entry->eax >> 16) & 0xff;
-		unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
-		unsigned phys_as = entry->eax & 0xff;
+		/*
+		 * GuestPhysAddrSize (EAX[23:16]) is intended for software
+		 * use.
+		 *
+		 * KVM's ABI is to report the effective MAXPHYADDR for the
+		 * guest in PhysAddrSize (phys_as), and the maximum
+		 * *addressable* GPA in GuestPhysAddrSize (g_phys_as).
+		 *
+		 * GuestPhysAddrSize is valid if and only if TDP is enabled,
+		 * in which case the max GPA that can be addressed by KVM may
+		 * be less than the max GPA that can be legally generated by
+		 * the guest, e.g. if MAXPHYADDR>48 but the CPU doesn't
+		 * support 5-level TDP.
+		 */
+		unsigned int virt_as = max((entry->eax >> 8) & 0xff, 48U);
+		unsigned int phys_as, g_phys_as;
 
 		/*
 		 * If TDP (NPT) is disabled use the adjusted host MAXPHYADDR as
@@ -1241,16 +1255,24 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		 * reductions in MAXPHYADDR for memory encryption affect shadow
 		 * paging, too.
 		 *
-		 * If TDP is enabled but an explicit guest MAXPHYADDR is not
-		 * provided, use the raw bare metal MAXPHYADDR as reductions to
-		 * the HPAs do not affect GPAs.
+		 * If TDP is enabled, use the raw bare metal MAXPHYADDR as
+		 * reductions to the HPAs do not affect GPAs.  The max
+		 * addressable GPA is the same as the max effective GPA, except
+		 * that it's capped at 48 bits if 5-level TDP isn't supported
+		 * (hardware processes bits 51:48 only when walking the fifth
+		 * level page table).
 		 */
-		if (!tdp_enabled)
-			g_phys_as = boot_cpu_data.x86_phys_bits;
-		else if (!g_phys_as)
+		if (!tdp_enabled) {
+			phys_as = boot_cpu_data.x86_phys_bits;
+			g_phys_as = 0;
+		} else {
+			phys_as = entry->eax & 0xff;
 			g_phys_as = phys_as;
+			if (kvm_mmu_get_max_tdp_level() < 5)
+				g_phys_as = min(g_phys_as, 48);
+		}
 
-		entry->eax = g_phys_as | (virt_as << 8);
+		entry->eax = phys_as | (virt_as << 8) | (g_phys_as << 16);
 		entry->ecx &= ~(GENMASK(31, 16) | GENMASK(11, 8));
 		entry->edx = 0;
 		cpuid_entry_override(entry, CPUID_8000_0008_EBX);