KVM: selftests: Add dedicated helpers for getting x86 Family and Model

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@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-11-seanjc@google.com

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)
@@ -516,6 +533,24 @@ 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)
 {
@@ -658,23 +693,6 @@ 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);

tools/testing/selftests/kvm/lib/x86_64/processor.c

@@ -1239,7 +1239,6 @@ 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;
@@ -1254,8 +1253,7 @@ 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;
 
 	/*