[PATCH v3 4/7] x86/cpu, kvm: Move CPUID 0x80000021 EAX feature bits propagation to kvm_set_cpu_caps

Kim Phillips
2022-11-29T23:59:46Z

Since they're now all scattered, group CPUID 0x80000021 EAX feature bits
propagation to kvm_set_cpu_caps instead of open-coding them in
__do_cpuid_func().

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/kvm/cpuid.c | 35 ++++++++++++++++++++---------------
arch/x86/kvm/reverse_cpuid.h | 22 ++++++++++++++++------
2 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index c92c49a0b35b..8e37760cea1b 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -730,6 +730,25 @@ void kvm_set_cpu_caps(void)
0 /* SME */ | F(SEV) | 0 /* VM_PAGE_FLUSH */ | F(SEV_ES) |
F(SME_COHERENT));

+ /*
+ * 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
+ * EAX 8 Automatic IBRS
+ *
+ * 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_cpu_cap_init_scattered(CPUID_8000_0021_EAX,
+ SF(NO_NESTED_DATA_BP) | SF(LFENCE_RDTSC) |
+ SF(NULL_SEL_CLR_BASE));
+ if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
+ kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC);
+ if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
+ kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE);
+
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) |
@@ -1211,21 +1230,7 @@ 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
- */
- entry->eax &= BIT(0) | BIT(2) | BIT(6);
- 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:
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index 4e5b8444f161..184614e27d5b 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -13,6 +13,7 @@
*/
enum kvm_only_cpuid_leafs {
CPUID_12_EAX = NCAPINTS,
+ CPUID_8000_0021_EAX,
NR_KVM_CPU_CAPS,

NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
@@ -25,6 +26,11 @@ enum kvm_only_cpuid_leafs {
#define KVM_X86_FEATURE_SGX2 KVM_X86_FEATURE(CPUID_12_EAX, 1)
#define KVM_X86_FEATURE_SGX_EDECCSSA KVM_X86_FEATURE(CPUID_12_EAX, 11)

+/* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX) */
+#define KVM_X86_FEATURE_NO_NESTED_DATA_BP KVM_X86_FEATURE(CPUID_8000_0021_EAX, 0)
+#define KVM_X86_FEATURE_LFENCE_RDTSC KVM_X86_FEATURE(CPUID_8000_0021_EAX, 2)
+#define KVM_X86_FEATURE_NULL_SEL_CLR_BASE KVM_X86_FEATURE(CPUID_8000_0021_EAX, 6)
+
struct cpuid_reg {
u32 function;
u32 index;
@@ -49,6 +55,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
[CPUID_7_1_EAX] = { 7, 1, CPUID_EAX},
[CPUID_12_EAX] = {0x00000012, 0, CPUID_EAX},
[CPUID_8000_001F_EAX] = {0x8000001f, 0, CPUID_EAX},
+ [CPUID_8000_0021_EAX] = {0x80000021, 0, CPUID_EAX},
};

/*
@@ -75,12 +82,15 @@ static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
*/
static __always_inline u32 __feature_translate(int x86_feature)
{
- if (x86_feature == X86_FEATURE_SGX1)
- return KVM_X86_FEATURE_SGX1;
- else if (x86_feature == X86_FEATURE_SGX2)
- return KVM_X86_FEATURE_SGX2;
- else if (x86_feature == X86_FEATURE_SGX_EDECCSSA)
- return KVM_X86_FEATURE_SGX_EDECCSSA;
+ switch (x86_feature) {
+ case X86_FEATURE_SGX1: return KVM_X86_FEATURE_SGX1;
+ case X86_FEATURE_SGX2: return KVM_X86_FEATURE_SGX2;
+ case X86_FEATURE_SGX_EDECCSSA: return KVM_X86_FEATURE_SGX_EDECCSSA;
+ case X86_FEATURE_NO_NESTED_DATA_BP: return KVM_X86_FEATURE_NO_NESTED_DATA_BP;
+ case X86_FEATURE_LFENCE_RDTSC: return KVM_X86_FEATURE_LFENCE_RDTSC;
+ case X86_FEATURE_NULL_SEL_CLR_BASE: return KVM_X86_FEATURE_NULL_SEL_CLR_BASE;
+ default: break;
+ }

return x86_feature;
}
--
2.34.1