[PATCH v8 2/8] x86/cpu, kvm: Move open-coded cpuid leaf 0x80000021 EAX bit propagation code

Kim Phillips
2023-01-23T22:58:15Z

Move code from __do_cpuid_func() to kvm_set_cpu_caps() in preparation
for adding the features in their native leaf.

Also drop the bit description comments as it will be more self-
describing once the individual features are added.

Whilst there, switch to using the more efficient cpu_feature_enabled()
instead of static_cpu_has().

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/kvm/cpuid.c | 30 +++++++++++-------------------
1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 596061c1610e..3930452bf06e 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -741,6 +741,16 @@ void kvm_set_cpu_caps(void)
0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) |
F(SME_COHERENT));

+ kvm_cpu_cap_mask(CPUID_8000_0021_EAX,
+ BIT(0) /* NO_NESTED_DATA_BP */ | 0 /* SmmPgCfgLock */ |
+ BIT(6) /* NULL_SEL_CLR_BASE */ | 0 /* PrefetchCtlMsr */
+ );
+ if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
+ kvm_cpu_caps[CPUID_8000_0021_EAX] |= BIT(2) /* LFENCE Always serializing */;
+ if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
+ kvm_cpu_caps[CPUID_8000_0021_EAX] |= BIT(6) /* NULL_SEL_CLR_BASE */;
+ kvm_cpu_caps[CPUID_8000_0021_EAX] |= BIT(9) /* NO_SMM_CTL_MSR */;
+
kvm_cpu_cap_mask(CPUID_C000_0001_EDX,
F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
@@ -1222,25 +1232,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
break;
case 0x80000021:
entry->ebx = entry->ecx = entry->edx = 0;
- /*
- * Pass down these bits:
- * EAX 0 NNDBP, Processor ignores nested data breakpoints
- * EAX 2 LAS, LFENCE always serializing
- * EAX 6 NSCB, Null selector clear base
- *
- * Other defined bits are for MSRs that KVM does not expose:
- * EAX 3 SPCL, SMM page configuration lock
- * EAX 13 PCMSR, Prefetch control MSR
- *
- * KVM doesn't support SMM_CTL.
- * EAX 9 SMM_CTL MSR is not supported
- */
- entry->eax &= BIT(0) | BIT(2) | BIT(6);
- entry->eax |= BIT(9);
- if (static_cpu_has(X86_FEATURE_LFENCE_RDTSC))
- entry->eax |= BIT(2);
- if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
- entry->eax |= BIT(6);
+ cpuid_entry_override(entry, CPUID_8000_0021_EAX);
break;
/*Add support for Centaur's CPUID instruction*/
case 0xC0000000:
--
2.34.1