@@ -1226,8 +1226,22 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->eax = entry->ebx = entry->ecx = 0;
break;
case 0x80000008: {
+ /*
+ * 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;
+ unsigned int phys_as, g_phys_as;
/*
* If TDP (NPT) is disabled use the adjusted host MAXPHYADDR as
@@ -1236,15 +1250,23 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
* paging, too.
*
* If TDP is enabled, use the raw bare metal MAXPHYADDR as
- * reductions to the HPAs do not affect GPAs.
+ * 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) {
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 = 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);
@@ -100,6 +100,8 @@ static inline u8 kvm_get_shadow_phys_bits(void)
return boot_cpu_data.x86_phys_bits;
}
+u8 kvm_mmu_get_max_tdp_level(void);
+
void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask);
void kvm_mmu_set_mmio_spte_value(struct kvm *kvm, u64 mmio_value);
void kvm_mmu_set_me_spte_mask(u64 me_value, u64 me_mask);
@@ -5419,6 +5419,11 @@ static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
return max_tdp_level;
}
+u8 kvm_mmu_get_max_tdp_level(void)
+{
+ return tdp_root_level ? tdp_root_level : max_tdp_level;
+}
+
static union kvm_mmu_page_role
kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
union kvm_cpu_role cpu_role)