[PATCH 10/12] KVM: selftests: Add dedicated helpers for getting x86 Family and Model

From: Sean Christopherson
Date: Wed Oct 05 2022 - 20:52:47 EST


Add dedicated helpers for getting x86's Family and Model, which are the
last holdouts that "need" raw access to CPUID information. FMS info is
a mess and requires not only splicing together multiple values, but
requires doing so conditional in the Family case.

Provide wrappers to reduce the odds of copy+paste errors, but mostly to
allow for the eventual removal of kvm_get_supported_cpuid_entry().

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/include/x86_64/processor.h | 52 +++++++++++++------
.../selftests/kvm/lib/x86_64/processor.c | 4 +-
2 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index acad7184d1b6..a1dafd4e8f43 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -247,6 +247,23 @@ struct kvm_x86_pmu_feature {

#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED KVM_X86_PMU_FEATURE(BRANCH_INSNS_RETIRED, 5)

+static inline unsigned int x86_family(unsigned int eax)
+{
+ unsigned int x86;
+
+ x86 = (eax >> 8) & 0xf;
+
+ if (x86 == 0xf)
+ x86 += (eax >> 20) & 0xff;
+
+ return x86;
+}
+
+static inline unsigned int x86_model(unsigned int eax)
+{
+ return ((eax >> 12) & 0xf0) | ((eax >> 4) & 0x0f);
+}
+
/* Page table bitfield declarations */
#define PTE_PRESENT_MASK BIT_ULL(0)
#define PTE_WRITABLE_MASK BIT_ULL(1)
@@ -510,6 +527,24 @@ static inline void cpuid(uint32_t function,
return __cpuid(function, 0, eax, ebx, ecx, edx);
}

+static inline uint32_t this_cpu_fms(void)
+{
+ uint32_t eax, ebx, ecx, edx;
+
+ cpuid(1, &eax, &ebx, &ecx, &edx);
+ return eax;
+}
+
+static inline uint32_t this_cpu_family(void)
+{
+ return x86_family(this_cpu_fms());
+}
+
+static inline uint32_t this_cpu_model(void)
+{
+ return x86_model(this_cpu_fms());
+}
+
static inline uint32_t __this_cpu_has(uint32_t function, uint32_t index,
uint8_t reg, uint8_t lo, uint8_t hi)
{
@@ -652,23 +687,6 @@ static inline void cpu_relax(void)
bool is_intel_cpu(void);
bool is_amd_cpu(void);

-static inline unsigned int x86_family(unsigned int eax)
-{
- unsigned int x86;
-
- x86 = (eax >> 8) & 0xf;
-
- if (x86 == 0xf)
- x86 += (eax >> 20) & 0xff;
-
- return x86;
-}
-
-static inline unsigned int x86_model(unsigned int eax)
-{
- return ((eax >> 12) & 0xf0) | ((eax >> 4) & 0x0f);
-}
-
struct kvm_x86_state *vcpu_save_state(struct kvm_vcpu *vcpu);
void vcpu_load_state(struct kvm_vcpu *vcpu, struct kvm_x86_state *state);
void kvm_x86_state_cleanup(struct kvm_x86_state *state);
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 99c309595c99..9fb949d63305 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1286,7 +1286,6 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
{
const unsigned long num_ht_pages = 12 << (30 - vm->page_shift); /* 12 GiB */
unsigned long ht_gfn, max_gfn, max_pfn;
- uint32_t eax, ebx, ecx, edx;
uint8_t maxphyaddr;

max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1;
@@ -1301,8 +1300,7 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)

/* Before family 17h, the HyperTransport area is just below 1T. */
ht_gfn = (1 << 28) - num_ht_pages;
- cpuid(1, &eax, &ebx, &ecx, &edx);
- if (x86_family(eax) < 0x17)
+ if (this_cpu_family() < 0x17)
goto done;

/*
--
2.38.0.rc1.362.ged0d419d3c-goog