[PATCH v8 20/30] KVM: selftests: TDX: Add TDX CPUID TDVMCALL test

[Sagi Shahar <sagis@google.com>]

This test issues a CPUID TDVMCALL from inside the guest to get the CPUID
values as seen by KVM.

Co-developed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
---
 .../selftests/kvm/include/x86/tdx/tdx.h       |  4 +
 tools/testing/selftests/kvm/lib/x86/tdx/tdx.c | 25 ++++++
 tools/testing/selftests/kvm/x86/tdx_vm_test.c | 78 ++++++++++++++++++-
 3 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
index 2fd67c3e5128..060158cb046b 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
@@ -9,6 +9,7 @@
 #define TDG_VP_VMCALL_GET_TD_VM_CALL_INFO 0x10000
 #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
 
+#define TDG_VP_VMCALL_INSTRUCTION_CPUID 10
 #define TDG_VP_VMCALL_INSTRUCTION_HLT 12
 #define TDG_VP_VMCALL_INSTRUCTION_IO 30
 #define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
@@ -27,5 +28,8 @@ uint64_t tdg_vp_vmcall_ve_request_mmio_read(uint64_t address, uint64_t size,
 					    uint64_t *data_out);
 uint64_t tdg_vp_vmcall_ve_request_mmio_write(uint64_t address, uint64_t size,
 					     uint64_t data_in);
+uint64_t tdg_vp_vmcall_instruction_cpuid(uint32_t eax, uint32_t ecx,
+					 uint32_t *ret_eax, uint32_t *ret_ebx,
+					 uint32_t *ret_ecx, uint32_t *ret_edx);
 
 #endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
index d61940fe7df4..fb391483d2fa 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
@@ -137,3 +137,28 @@ uint64_t tdg_vp_vmcall_ve_request_mmio_write(uint64_t address, uint64_t size,
 
 	return __tdx_hypercall(&args, 0);
 }
+
+uint64_t tdg_vp_vmcall_instruction_cpuid(uint32_t eax, uint32_t ecx,
+					 uint32_t *ret_eax, uint32_t *ret_ebx,
+					 uint32_t *ret_ecx, uint32_t *ret_edx)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_INSTRUCTION_CPUID,
+		.r12 = eax,
+		.r13 = ecx,
+	};
+	uint64_t ret;
+
+	ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+	if (ret_eax)
+		*ret_eax = args.r12;
+	if (ret_ebx)
+		*ret_ebx = args.r13;
+	if (ret_ecx)
+		*ret_ecx = args.r14;
+	if (ret_edx)
+		*ret_edx = args.r15;
+
+	return ret;
+}
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
index 6ad675a93eeb..2f75f12d2a44 100644
--- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c
+++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
@@ -885,6 +885,80 @@ void verify_mmio_writes(void)
 	printf("\t ... PASSED\n");
 }
 
+/*
+ * Verifies CPUID TDVMCALL functionality.
+ * The guest will then send the values to userspace using an IO write to be
+ * checked against the expected values.
+ */
+void guest_code_cpuid_tdcall(void)
+{
+	uint32_t eax, ebx, ecx, edx;
+	uint64_t err;
+
+	/* Read CPUID leaf 0x1 from host. */
+	err = tdg_vp_vmcall_instruction_cpuid(/*eax=*/1, /*ecx=*/0,
+					      &eax, &ebx, &ecx, &edx);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_to_user_space(eax);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_to_user_space(ebx);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_to_user_space(ecx);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_to_user_space(edx);
+	tdx_assert_error(err);
+
+	tdx_test_success();
+}
+
+void verify_td_cpuid_tdcall(void)
+{
+	struct kvm_cpuid_entry2 *cpuid_entry;
+	uint32_t eax, ebx, ecx, edx;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_code_cpuid_tdcall);
+	td_finalize(vm);
+
+	printf("Verifying TD CPUID TDVMCALL:\n");
+
+	/* Wait for guest to report CPUID values */
+	tdx_run(vcpu);
+	eax = tdx_test_read_report_from_guest(vcpu);
+
+	tdx_run(vcpu);
+	ebx = tdx_test_read_report_from_guest(vcpu);
+
+	tdx_run(vcpu);
+	ecx = tdx_test_read_report_from_guest(vcpu);
+
+	tdx_run(vcpu);
+	edx = tdx_test_read_report_from_guest(vcpu);
+
+	tdx_run(vcpu);
+	tdx_test_assert_success(vcpu);
+
+	/* Get KVM CPUIDs for reference */
+	cpuid_entry = vcpu_get_cpuid_entry(vcpu, 1);
+	TEST_ASSERT(cpuid_entry, "CPUID entry missing\n");
+
+	TEST_ASSERT_EQ(cpuid_entry->eax, eax);
+	/* Mask lapic ID when comparing ebx. */
+	TEST_ASSERT_EQ(cpuid_entry->ebx & ~0xFF000000, ebx & ~0xFF000000);
+	TEST_ASSERT_EQ(cpuid_entry->ecx, ecx);
+	TEST_ASSERT_EQ(cpuid_entry->edx, edx);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
 int main(int argc, char **argv)
 {
 	ksft_print_header();
@@ -892,7 +966,7 @@ int main(int argc, char **argv)
 	if (!is_tdx_enabled())
 		ksft_exit_skip("TDX is not supported by the KVM. Exiting.\n");
 
-	ksft_set_plan(12);
+	ksft_set_plan(13);
 	ksft_test_result(!run_in_new_process(&verify_td_lifecycle),
 			 "verify_td_lifecycle\n");
 	ksft_test_result(!run_in_new_process(&verify_report_fatal_error),
@@ -917,6 +991,8 @@ int main(int argc, char **argv)
 			 "verify_mmio_reads\n");
 	ksft_test_result(!run_in_new_process(&verify_mmio_writes),
 			 "verify_mmio_writes\n");
+	ksft_test_result(!run_in_new_process(&verify_td_cpuid_tdcall),
+			 "verify_td_cpuid_tdcall\n");
 
 	ksft_finished();
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog