[PATCH v2] KVM: x86: Advertise SUCCOR and OVERFLOW_RECOV cpuid bits

John Allen
2024-07-31T14:37:39Z

Handling deferred, uncorrected MCEs on AMD guests is now possible with
additional support in qemu. Ensure that the SUCCOR and OVERFLOW_RECOV
bits are advertised to the guest in KVM.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Allen <john.allen@amd.com>
---
v2:
- Add cpuid_entry_override for CPUID_8000_0007_EBX.
- Handle masking bits in arch/x86/kvm/cpuid.c
---
arch/x86/kvm/cpuid.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 2617be544480..f8e1fd409cee 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -743,6 +743,11 @@ void kvm_set_cpu_caps(void)
if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64))
kvm_cpu_cap_set(X86_FEATURE_GBPAGES);

+ kvm_cpu_cap_mask(CPUID_8000_0007_EBX,
+ F(OVERFLOW_RECOV) |
+ F(SUCCOR)
+ );
+
kvm_cpu_cap_init_kvm_defined(CPUID_8000_0007_EDX,
SF(CONSTANT_TSC)
);
@@ -1237,11 +1242,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->edx &= ~GENMASK(17, 16);
break;
case 0x80000007: /* Advanced power management */
+ cpuid_entry_override(entry, CPUID_8000_0007_EBX);
cpuid_entry_override(entry, CPUID_8000_0007_EDX);

/* mask against host */
entry->edx &= boot_cpu_data.x86_power;
- entry->eax = entry->ebx = entry->ecx = 0;
+ entry->eax = entry->ecx = 0;
break;
case 0x80000008: {
/*
--
2.34.1