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Diffstat (limited to 'arch/x86/kvm/cpuid.c')
-rw-r--r--arch/x86/kvm/cpuid.c30
1 files changed, 26 insertions, 4 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b1002b7988..f2f2be5d11 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -772,7 +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,
@@ -1232,8 +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: {
+ /*
+ * 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
@@ -1242,15 +1256,23 @@ 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);