[RFC PATCH v3 15/31] KVM: selftests: TDX: Add TDX IO reads test

[Ackerley Tng <ackerleytng@xxxxxxxxxx>]

From: Sagi Shahar <sagis@xxxxxxxxxx>

The test verifies IO reads of various sizes from the host to the guest.

Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
 .../selftests/kvm/x86_64/tdx_vm_tests.c       | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
index ac23d1ad1e687..71aa4e5907a05 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -428,6 +428,92 @@ void verify_guest_writes(void)
 	printf("\t ... PASSED\n");
 }
 
+#define TDX_IO_READS_TEST_PORT 0x52
+
+/*
+ * Verifies IO functionality by reading values of different sizes
+ * from the host.
+ */
+void guest_io_reads(void)
+{
+	uint64_t data;
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_instruction_io(TDX_IO_READS_TEST_PORT, 1,
+					TDG_VP_VMCALL_INSTRUCTION_IO_READ,
+					&data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0xAB)
+		tdx_test_fatal(1);
+
+	ret = tdg_vp_vmcall_instruction_io(TDX_IO_READS_TEST_PORT, 2,
+					TDG_VP_VMCALL_INSTRUCTION_IO_READ,
+					&data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0xABCD)
+		tdx_test_fatal(2);
+
+	ret = tdg_vp_vmcall_instruction_io(TDX_IO_READS_TEST_PORT, 4,
+					TDG_VP_VMCALL_INSTRUCTION_IO_READ,
+					&data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0xFFABCDEF)
+		tdx_test_fatal(4);
+
+	// Read an invalid number of bytes.
+	ret = tdg_vp_vmcall_instruction_io(TDX_IO_READS_TEST_PORT, 5,
+					TDG_VP_VMCALL_INSTRUCTION_IO_READ,
+					&data);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	tdx_test_success();
+}
+
+void verify_guest_reads(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_io_reads);
+	td_finalize(vm);
+
+	printf("Verifying guest reads:\n");
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_IO(vcpu, TDX_IO_READS_TEST_PORT, 1,
+			TDG_VP_VMCALL_INSTRUCTION_IO_READ);
+	*(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset) = 0xAB;
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_IO(vcpu, TDX_IO_READS_TEST_PORT, 2,
+			TDG_VP_VMCALL_INSTRUCTION_IO_READ);
+	*(uint16_t *)((void *)vcpu->run + vcpu->run->io.data_offset) = 0xABCD;
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_IO(vcpu, TDX_IO_READS_TEST_PORT, 4,
+			TDG_VP_VMCALL_INSTRUCTION_IO_READ);
+	*(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset) = 0xFFABCDEF;
+
+	vcpu_run(vcpu);
+	ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
+	ASSERT_EQ(vcpu->run->system_event.data[1], TDG_VP_VMCALL_INVALID_OPERAND);
+
+	vcpu_run(vcpu);
+	TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
 int main(int argc, char **argv)
 {
 	setbuf(stdout, NULL);
@@ -443,6 +529,7 @@ int main(int argc, char **argv)
 	run_in_new_process(&verify_td_cpuid);
 	run_in_new_process(&verify_get_td_vmcall_info);
 	run_in_new_process(&verify_guest_writes);
+	run_in_new_process(&verify_guest_reads);
 
 	return 0;
 }
-- 
2.39.0.246.g2a6d74b583-goog