KVM: selftests: x86: Cache host CPU vendor (AMD vs. Intel)

Cache the host CPU vendor for userspace and share it with guest code.

All the current callers of this_cpu* actually care about host cpu so
they are updated to check host_cpu_is*.

Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20230111004445.416840-3-vannapurve@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

tools/testing/selftests/kvm/include/x86_64/processor.h

@@ -19,6 +19,9 @@
 
 #include "../kvm_util.h"
 
+extern bool host_cpu_is_intel;
+extern bool host_cpu_is_amd;
+
 #define NMI_VECTOR		0x02
 
 #define X86_EFLAGS_FIXED	 (1u << 1)

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

@@ -19,6 +19,8 @@
 #define MAX_NR_CPUID_ENTRIES 100
 
 vm_vaddr_t exception_handlers;
+bool host_cpu_is_amd;
+bool host_cpu_is_intel;
 
 static void regs_dump(FILE *stream, struct kvm_regs *regs, uint8_t indent)
 {
@@ -113,7 +115,7 @@ static void sregs_dump(FILE *stream, struct kvm_sregs *sregs, uint8_t indent)
 
 bool kvm_is_tdp_enabled(void)
 {
-	if (this_cpu_is_intel())
+	if (host_cpu_is_intel)
 		return get_kvm_intel_param_bool("ept");
 	else
 		return get_kvm_amd_param_bool("npt");
@@ -555,6 +557,8 @@ static void vcpu_setup(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
 void kvm_arch_vm_post_create(struct kvm_vm *vm)
 {
 	vm_create_irqchip(vm);
+	sync_global_to_guest(vm, host_cpu_is_intel);
+	sync_global_to_guest(vm, host_cpu_is_amd);
 }
 
 struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id,
@@ -1214,7 +1218,7 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
 	max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1;
 
 	/* Avoid reserved HyperTransport region on AMD processors.  */
-	if (!this_cpu_is_amd())
+	if (!host_cpu_is_amd)
 		return max_gfn;
 
 	/* On parts with <40 physical address bits, the area is fully hidden */
@@ -1254,3 +1258,9 @@ bool vm_is_unrestricted_guest(struct kvm_vm *vm)
 
 	return get_kvm_intel_param_bool("unrestricted_guest");
 }
+
+void kvm_selftest_arch_init(void)
+{
+	host_cpu_is_intel = this_cpu_is_intel();
+	host_cpu_is_amd = this_cpu_is_amd();
+}

tools/testing/selftests/kvm/x86_64/fix_hypercall_test.c

@@ -48,10 +48,10 @@ static void guest_main(void)
 	const uint8_t *other_hypercall_insn;
 	uint64_t ret;
 
-	if (this_cpu_is_intel()) {
+	if (host_cpu_is_intel) {
 		native_hypercall_insn = vmx_vmcall;
 		other_hypercall_insn  = svm_vmmcall;
-	} else if (this_cpu_is_amd()) {
+	} else if (host_cpu_is_amd) {
 		native_hypercall_insn = svm_vmmcall;
 		other_hypercall_insn  = vmx_vmcall;
 	} else {

tools/testing/selftests/kvm/x86_64/mmio_warning_test.c

@@ -93,7 +93,7 @@ int main(void)
 {
 	int warnings_before, warnings_after;
 
-	TEST_REQUIRE(this_cpu_is_intel());
+	TEST_REQUIRE(host_cpu_is_intel);
 
 	TEST_REQUIRE(!vm_is_unrestricted_guest(NULL));
 

tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c

@@ -363,7 +363,7 @@ static void test_pmu_config_disable(void (*guest_code)(void))
  */
 static bool use_intel_pmu(void)
 {
-	return this_cpu_is_intel() &&
+	return host_cpu_is_intel &&
 	       kvm_cpu_property(X86_PROPERTY_PMU_VERSION) &&
 	       kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS) &&
 	       kvm_pmu_has(X86_PMU_FEATURE_BRANCH_INSNS_RETIRED);
@@ -397,7 +397,7 @@ static bool use_amd_pmu(void)
 	uint32_t family = kvm_cpu_family();
 	uint32_t model = kvm_cpu_model();
 
-	return this_cpu_is_amd() &&
+	return host_cpu_is_amd &&
 		(is_zen1(family, model) ||
 		 is_zen2(family, model) ||
 		 is_zen3(family, model));

tools/testing/selftests/kvm/x86_64/vmx_exception_with_invalid_guest_state.c

@@ -111,7 +111,7 @@ int main(int argc, char *argv[])
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
 
-	TEST_REQUIRE(this_cpu_is_intel());
+	TEST_REQUIRE(host_cpu_is_intel);
 	TEST_REQUIRE(!vm_is_unrestricted_guest(NULL));
 
 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);