KVM: selftests: Extend vmx_nested_tsc_scaling_test to cover SVM

Add SVM L1 code to run the nested guest, and allow the test to run with
SVM as well as VMX.

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20251021074736.1324328-5-yosry.ahmed@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: yosrym93

tools/testing/selftests/kvm/Makefile.kvm

@@ -91,6 +91,7 @@ TEST_GEN_PROGS_x86 += x86/msrs_test
 TEST_GEN_PROGS_x86 += x86/nested_close_kvm_test
 TEST_GEN_PROGS_x86 += x86/nested_emulation_test
 TEST_GEN_PROGS_x86 += x86/nested_exceptions_test
+TEST_GEN_PROGS_x86 += x86/nested_tsc_scaling_test
 TEST_GEN_PROGS_x86 += x86/platform_info_test
 TEST_GEN_PROGS_x86 += x86/pmu_counters_test
 TEST_GEN_PROGS_x86 += x86/pmu_event_filter_test
@@ -118,7 +119,6 @@ TEST_GEN_PROGS_x86 += x86/vmx_msrs_test
 TEST_GEN_PROGS_x86 += x86/vmx_invalid_nested_guest_state
 TEST_GEN_PROGS_x86 += x86/vmx_set_nested_state_test
 TEST_GEN_PROGS_x86 += x86/vmx_tsc_adjust_test
-TEST_GEN_PROGS_x86 += x86/vmx_nested_tsc_scaling_test
 TEST_GEN_PROGS_x86 += x86/apic_bus_clock_test
 TEST_GEN_PROGS_x86 += x86/xapic_ipi_test
 TEST_GEN_PROGS_x86 += x86/xapic_state_test

tools/testing/selftests/kvm/x86/vmx_nested_tsc_scaling_test.c renamed to tools/testing/selftests/kvm/x86/nested_tsc_scaling_test.c

@@ -13,6 +13,7 @@
 
 #include "kvm_util.h"
 #include "vmx.h"
+#include "svm_util.h"
 #include "kselftest.h"
 
 /* L2 is scaled up (from L1's perspective) by this factor */
@@ -79,7 +80,30 @@ static void l2_guest_code(void)
 	__asm__ __volatile__("vmcall");
 }
 
-static void l1_guest_code(struct vmx_pages *vmx_pages)
+static void l1_svm_code(struct svm_test_data *svm)
+{
+	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+
+	/* check that L1's frequency looks alright before launching L2 */
+	check_tsc_freq(UCHECK_L1);
+
+	generic_svm_setup(svm, l2_guest_code,
+			  &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+
+	/* enable TSC scaling for L2 */
+	wrmsr(MSR_AMD64_TSC_RATIO, L2_SCALE_FACTOR << 32);
+
+	/* launch L2 */
+	run_guest(svm->vmcb, svm->vmcb_gpa);
+	GUEST_ASSERT(svm->vmcb->control.exit_code == SVM_EXIT_VMMCALL);
+
+	/* check that L1's frequency still looks good */
+	check_tsc_freq(UCHECK_L1);
+
+	GUEST_DONE();
+}
+
+static void l1_vmx_code(struct vmx_pages *vmx_pages)
 {
 	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
 	uint32_t control;
@@ -116,11 +140,19 @@ static void l1_guest_code(struct vmx_pages *vmx_pages)
 	GUEST_DONE();
 }
 
+static void l1_guest_code(void *data)
+{
+	if (this_cpu_has(X86_FEATURE_VMX))
+		l1_vmx_code(data);
+	else
+		l1_svm_code(data);
+}
+
 int main(int argc, char *argv[])
 {
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
-	vm_vaddr_t vmx_pages_gva;
+	vm_vaddr_t guest_gva = 0;
 
 	uint64_t tsc_start, tsc_end;
 	uint64_t tsc_khz;
@@ -129,7 +161,8 @@ int main(int argc, char *argv[])
 	uint64_t l1_tsc_freq = 0;
 	uint64_t l2_tsc_freq = 0;
 
-	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
+	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX) ||
+		     kvm_cpu_has(X86_FEATURE_SVM));
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_TSC_CONTROL));
 	TEST_REQUIRE(sys_clocksource_is_based_on_tsc());
 
@@ -152,8 +185,13 @@ int main(int argc, char *argv[])
 	printf("real TSC frequency is around: %"PRIu64"\n", l0_tsc_freq);
 
 	vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
-	vcpu_alloc_vmx(vm, &vmx_pages_gva);
-	vcpu_args_set(vcpu, 1, vmx_pages_gva);
+
+	if (kvm_cpu_has(X86_FEATURE_VMX))
+		vcpu_alloc_vmx(vm, &guest_gva);
+	else
+		vcpu_alloc_svm(vm, &guest_gva);
+
+	vcpu_args_set(vcpu, 1, guest_gva);
 
 	tsc_khz = __vcpu_ioctl(vcpu, KVM_GET_TSC_KHZ, NULL);
 	TEST_ASSERT(tsc_khz != -1, "vcpu ioctl KVM_GET_TSC_KHZ failed");