[PATCH v8 19/30] KVM: selftests: TDX: Add TDX MMIO writes test

[Sagi Shahar <sagis@google.com>]

The test verifies MMIO writes of various sizes from the guest to the host.

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       |  2 +
 tools/testing/selftests/kvm/lib/x86/tdx/tdx.c | 14 +++
 tools/testing/selftests/kvm/x86/tdx_vm_test.c | 85 ++++++++++++++++++-
 3 files changed, 100 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 fa0b24873a8f..2fd67c3e5128 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
@@ -25,5 +25,7 @@ uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value);
 uint64_t tdg_vp_vmcall_instruction_hlt(uint64_t interrupt_blocked_flag);
 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);
 
 #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 8bf41e667fc1..d61940fe7df4 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
@@ -123,3 +123,17 @@ uint64_t tdg_vp_vmcall_ve_request_mmio_read(uint64_t address, uint64_t size,
 
 	return ret;
 }
+
+uint64_t tdg_vp_vmcall_ve_request_mmio_write(uint64_t address, uint64_t size,
+					     uint64_t data_in)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_VE_REQUEST_MMIO,
+		.r12 = size,
+		.r13 = MMIO_WRITE,
+		.r14 = address,
+		.r15 = data_in,
+	};
+
+	return __tdx_hypercall(&args, 0);
+}
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
index 563f1025c8a3..6ad675a93eeb 100644
--- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c
+++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
@@ -804,6 +804,87 @@ void verify_mmio_reads(void)
 	printf("\t ... PASSED\n");
 }
 
+void guest_mmio_writes(void)
+{
+	uint64_t mmio_test_addr = TDX_MMIO_TEST_ADDR | tdx_s_bit;
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(mmio_test_addr, 1, 0x12);
+	tdx_assert_error(ret);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(mmio_test_addr, 2, 0x1234);
+	tdx_assert_error(ret);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(mmio_test_addr, 4, 0x12345678);
+	tdx_assert_error(ret);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(mmio_test_addr, 8, 0x1234567890ABCDEF);
+	tdx_assert_error(ret);
+
+	/* Make sure host and guest are synced to the same point of execution */
+	tdx_test_report_to_user_space(MMIO_SYNC_VALUE);
+
+	/* Write across page boundary. */
+	ret = tdg_vp_vmcall_ve_request_mmio_write(PAGE_SIZE - 1, 8, 0);
+	tdx_assert_error(ret);
+
+	tdx_test_success();
+}
+
+/*
+ * Verifies guest MMIO writes.
+ */
+void verify_mmio_writes(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	uint64_t byte_8;
+	uint32_t byte_4;
+	uint16_t byte_2;
+	uint8_t byte_1;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_mmio_writes);
+	td_finalize(vm);
+
+	printf("Verifying TD MMIO writes:\n");
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 1, MMIO_WRITE);
+	byte_1 = *(uint8_t *)(vcpu->run->mmio.data);
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 2, MMIO_WRITE);
+	byte_2 = *(uint16_t *)(vcpu->run->mmio.data);
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 4, MMIO_WRITE);
+	byte_4 = *(uint32_t *)(vcpu->run->mmio.data);
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 8, MMIO_WRITE);
+	byte_8 = *(uint64_t *)(vcpu->run->mmio.data);
+
+	TEST_ASSERT_EQ(byte_1, 0x12);
+	TEST_ASSERT_EQ(byte_2, 0x1234);
+	TEST_ASSERT_EQ(byte_4, 0x12345678);
+	TEST_ASSERT_EQ(byte_8, 0x1234567890ABCDEF);
+
+	tdx_run(vcpu);
+	TEST_ASSERT_EQ(tdx_test_read_report_from_guest(vcpu), MMIO_SYNC_VALUE);
+
+	td_vcpu_run(vcpu);
+	TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
+	TEST_ASSERT_EQ(vcpu->run->system_event.data[12], TDG_VP_VMCALL_INVALID_OPERAND);
+
+	tdx_run(vcpu);
+	tdx_test_assert_success(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
 int main(int argc, char **argv)
 {
 	ksft_print_header();
@@ -811,7 +892,7 @@ 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(11);
+	ksft_set_plan(12);
 	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),
@@ -834,6 +915,8 @@ int main(int argc, char **argv)
 			 "verify_guest_hlt\n");
 	ksft_test_result(!run_in_new_process(&verify_mmio_reads),
 			 "verify_mmio_reads\n");
+	ksft_test_result(!run_in_new_process(&verify_mmio_writes),
+			 "verify_mmio_writes\n");
 
 	ksft_finished();
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog