[PATCH v8 11/30] KVM: selftests: TDX: Adding test case for TDX port IO

[Sagi Shahar <sagis@google.com>]

Verifies TDVMCALL<INSTRUCTION.IO> READ and WRITE operations.

Signed-off-by: Sagi Shahar <sagis@google.com>
---
 .../selftests/kvm/include/x86/tdx/test_util.h | 20 +++++
 .../selftests/kvm/lib/x86/tdx/test_util.c     | 35 +++++++++
 tools/testing/selftests/kvm/x86/tdx_vm_test.c | 78 ++++++++++++++++++-
 3 files changed, 130 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
index dafeee9af1dc..cf11955d56d6 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
@@ -13,6 +13,19 @@
 #define PORT_READ	0
 #define PORT_WRITE	1
 
+/*
+ * Assert that some IO operation involving tdg_vp_vmcall_instruction_io() was
+ * called in the guest.
+ */
+void tdx_test_assert_io(struct kvm_vcpu *vcpu, uint16_t port, uint8_t size,
+			uint8_t direction);
+
+/*
+ * Run the tdx vcpu and check if there was some failure in the guest, either
+ * an exception like a triple fault, or if a tdx_test_fatal() was hit.
+ */
+void tdx_run(struct kvm_vcpu *vcpu);
+
 /*
  * Run a test in a new process.
  *
@@ -57,4 +70,11 @@ void tdx_test_fatal(uint64_t error_code);
  */
 void tdx_test_fatal_with_data(uint64_t error_code, uint64_t data_gpa);
 
+/*
+ * Assert on @error and report the @error to userspace.
+ * Return value from tdg_vp_vmcall_report_fatal_error() is ignored since execution
+ * is not expected to continue beyond this point.
+ */
+void tdx_assert_error(uint64_t error);
+
 #endif // SELFTEST_TDX_TEST_UTIL_H
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
index 6c82a0c3bd37..4ccc5298ba25 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
@@ -8,8 +8,37 @@
 
 #include "kvm_util.h"
 #include "tdx/tdx.h"
+#include "tdx/tdx_util.h"
 #include "tdx/test_util.h"
 
+void tdx_test_assert_io(struct kvm_vcpu *vcpu, uint16_t port, uint8_t size,
+			uint8_t direction)
+{
+	TEST_ASSERT(vcpu->run->exit_reason == KVM_EXIT_IO,
+		    "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
+		    vcpu->run->exit_reason,
+		    exit_reason_str(vcpu->run->exit_reason));
+
+	TEST_ASSERT(vcpu->run->exit_reason == KVM_EXIT_IO &&
+		    vcpu->run->io.port == port &&
+		    vcpu->run->io.size == size &&
+		    vcpu->run->io.direction == direction,
+		    "Got unexpected IO exit values: %u (%s) %u %u %u\n",
+		    vcpu->run->exit_reason,
+		    exit_reason_str(vcpu->run->exit_reason),
+		    vcpu->run->io.port, vcpu->run->io.size,
+		    vcpu->run->io.direction);
+}
+
+void tdx_run(struct kvm_vcpu *vcpu)
+{
+	td_vcpu_run(vcpu);
+	if (vcpu->run->exit_reason == KVM_EXIT_SYSTEM_EVENT)
+		TEST_FAIL("Guest reported error. error code: %lld (0x%llx)\n",
+			  vcpu->run->system_event.data[12],
+			  vcpu->run->system_event.data[13]);
+}
+
 int run_in_new_process(void (*func)(void))
 {
 	int wstatus;
@@ -69,3 +98,9 @@ void tdx_test_fatal(uint64_t error_code)
 {
 	tdx_test_fatal_with_data(error_code, 0);
 }
+
+void tdx_assert_error(uint64_t error)
+{
+	if (error)
+		tdx_test_fatal(error);
+}
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
index 7d6d71602761..97330e28f236 100644
--- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c
+++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
@@ -3,6 +3,7 @@
 #include <signal.h>
 
 #include "kvm_util.h"
+#include "tdx/tdcall.h"
 #include "tdx/tdx.h"
 #include "tdx/tdx_util.h"
 #include "tdx/test_util.h"
@@ -25,7 +26,7 @@ static void verify_td_lifecycle(void)
 
 	printf("Verifying TD lifecycle:\n");
 
-	td_vcpu_run(vcpu);
+	tdx_run(vcpu);
 	tdx_test_assert_success(vcpu);
 
 	kvm_vm_free(vm);
@@ -69,9 +70,78 @@ void verify_report_fatal_error(void)
 	TEST_ASSERT_EQ(vcpu->run->system_event.data[12], 0x0BAAAAAD00000000);
 	TEST_ASSERT_EQ(vcpu->run->system_event.data[13], 0);
 
-	td_vcpu_run(vcpu);
+	tdx_run(vcpu);
+	tdx_test_assert_success(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
+#define TDX_IOEXIT_TEST_PORT 0x50
+
+/*
+ * Verifies IO functionality by writing a |value| to a predefined port.
+ * Verifies that the read value is |value| + 1 from the same port.
+ * If all the tests are passed then write a value to port TDX_TEST_PORT
+ */
+void guest_ioexit(void)
+{
+	uint64_t data_out, data_in;
+	uint64_t ret;
+
+	data_out = 0xAB;
+	ret = tdg_vp_vmcall_instruction_io(TDX_IOEXIT_TEST_PORT, 1,
+					   PORT_WRITE, &data_out);
+	tdx_assert_error(ret);
+
+	ret = tdg_vp_vmcall_instruction_io(TDX_IOEXIT_TEST_PORT, 1,
+					   PORT_READ, &data_in);
+	tdx_assert_error(ret);
+
+	if (data_in != 0xAC)
+		tdx_test_fatal(data_in);
+
+	tdx_test_success();
+}
+
+void verify_td_ioexit(void)
+{
+	struct kvm_vcpu *vcpu;
+	uint32_t port_data;
+	struct kvm_vm *vm;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_ioexit);
+	td_finalize(vm);
+
+	printf("Verifying TD IO Exit:\n");
+
+	/* Wait for guest to do a IO write */
+	tdx_run(vcpu);
+	tdx_test_assert_io(vcpu, TDX_IOEXIT_TEST_PORT, 1, PORT_WRITE);
+	port_data = *(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+	printf("\t ... IO WRITE: DONE\n");
+
+	/*
+	 * Wait for the guest to do a IO read. Provide the previous written data
+	 * + 1 back to the guest
+	 */
+	tdx_run(vcpu);
+	tdx_test_assert_io(vcpu, TDX_IOEXIT_TEST_PORT, 1, PORT_READ);
+	*(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset) = port_data + 1;
+
+	printf("\t ... IO READ: DONE\n");
+
+	/*
+	 * Wait for the guest to complete execution successfully. The read
+	 * value is checked within the guest.
+	 */
+	tdx_run(vcpu);
 	tdx_test_assert_success(vcpu);
 
+	printf("\t ... IO verify read/write values: OK\n");
 	kvm_vm_free(vm);
 	printf("\t ... PASSED\n");
 }
@@ -83,11 +153,13 @@ 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(2);
+	ksft_set_plan(3);
 	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),
 			 "verify_report_fatal_error\n");
+	ksft_test_result(!run_in_new_process(&verify_td_ioexit),
+			 "verify_td_ioexit\n");
 
 	ksft_finished();
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog