On Thu, Jul 04, 2024, Maxim Levitsky wrote:
> On Fri, 2024-05-17 at 10:38 -0700, Sean Christopherson wrote:
> > +/*
> > + * Raw Feature - For features that KVM supports based purely on raw host CPUID,
> > + * i.e. that KVM virtualizes even if the host kernel doesn't use the feature.
> > + * Simply force set the feature in KVM's capabilities, raw CPUID support will
> > + * be factored in by kvm_cpu_cap_mask().
> > + */
> > +#define RAW_F(name) \
> > +({ \
> > + kvm_cpu_cap_set(X86_FEATURE_##name); \
> > + F(name); \
> > +})
> > +
> > /*
> > * Magic value used by KVM when querying userspace-provided CPUID entries and
> > * doesn't care about the CPIUD index because the index of the function in
> > @@ -682,15 +694,12 @@ void kvm_set_cpu_caps(void)
> > F(AVX512VL));
> >
> > kvm_cpu_cap_mask(CPUID_7_ECX,
> > - F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) |
> > + F(AVX512VBMI) | RAW_F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) |
> > F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
> > F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
> > F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/ |
> > F(SGX_LC) | F(BUS_LOCK_DETECT)
> > );
> > - /* Set LA57 based on hardware capability. */
> > - if (cpuid_ecx(7) & F(LA57))
> > - kvm_cpu_cap_set(X86_FEATURE_LA57);
> >
> > /*
> > * PKU not yet implemented for shadow paging and requires OSPKE
>
> Putting a function call into a macro which evaluates into a bitmask is somewhat misleading,
> but let it be...
And weird. Rather than abuse kvm_cpu_cap_set(), what about adding another variable
scoped to kvm_cpu_cap_init()?
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 0e64a6332052..b8bc8713a0ec 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -87,12 +87,10 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted)
/*
* Raw Feature - For features that KVM supports based purely on raw host CPUID,
* i.e. that KVM virtualizes even if the host kernel doesn't use the feature.
- * Simply force set the feature in KVM's capabilities, raw CPUID support will
- * be factored in by __kvm_cpu_cap_mask().
*/
#define RAW_F(name) \
({ \
- kvm_cpu_cap_set(X86_FEATURE_##name); \
+ kvm_cpu_cap_passthrough |= F(name); \
F(name); \
})
@@ -737,6 +735,7 @@ do { \
do { \
const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); \
const u32 __maybe_unused kvm_cpu_cap_init_in_progress = leaf; \
+ u32 kvm_cpu_cap_passthrough = 0; \
u32 kvm_cpu_cap_emulated = 0; \
u32 kvm_cpu_cap_synthesized = 0; \
\
@@ -745,6 +744,7 @@ do { \
else \
kvm_cpu_caps[leaf] = (mask); \
\
+ kvm_cpu_caps[leaf] |= kvm_cpu_cap_passthrough; \
kvm_cpu_caps[leaf] &= (raw_cpuid_get(cpuid) | \
kvm_cpu_cap_synthesized); \
kvm_cpu_caps[leaf] |= kvm_cpu_cap_emulated; \
