[RFC PATCH v3 19/31] KVM: selftests: TDX: Add TDX MMIO writes test

[Ackerley Tng]

From: Sagi Shahar <sagis@xxxxxxxxxx>

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

Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
 .../selftests/kvm/include/x86_64/tdx/tdx.h    |  2 +
 .../selftests/kvm/lib/x86_64/tdx/tdx.c        | 14 +++
 .../selftests/kvm/x86_64/tdx_vm_tests.c       | 85 +++++++++++++++++++
 3 files changed, 101 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
index 8dd6a65485260..f2a90ad8a55c6 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
@@ -24,5 +24,7 @@ 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_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
index dcdacf08bcd60..8b12ac7049572 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -122,3 +122,17 @@ 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 = TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE,
+		.r14 = address,
+		.r15 = data_in,
+	};
+
+	return __tdx_hypercall(&args, 0);
+}
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 88f0429db0176..dcc0940a74e92 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -892,6 +892,90 @@ void verify_mmio_reads(void)
 	printf("\t ... PASSED\n");
 }
 
+void guest_mmio_writes(void)
+{
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(TDX_MMIO_TEST_ADDR, 1, 0x12);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(TDX_MMIO_TEST_ADDR, 2, 0x1234);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(TDX_MMIO_TEST_ADDR, 4, 0x12345678);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_write(TDX_MMIO_TEST_ADDR, 8, 0x1234567890ABCDEF);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	// Write across page boundary.
+	ret = tdg_vp_vmcall_ve_request_mmio_write(PAGE_SIZE - 1, 8, 0);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	tdx_test_success();
+}
+
+/*
+ * Varifies guest MMIO writes.
+ */
+void verify_mmio_writes(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+
+	uint8_t byte_1;
+	uint16_t byte_2;
+	uint32_t byte_4;
+	uint64_t byte_8;
+
+	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");
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 1, TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE);
+	byte_1 = *(uint8_t *)(vcpu->run->mmio.data);
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 2, TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE);
+	byte_2 = *(uint16_t *)(vcpu->run->mmio.data);
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 4, TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE);
+	byte_4 = *(uint32_t *)(vcpu->run->mmio.data);
+
+	vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 8, TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE);
+	byte_8 = *(uint64_t *)(vcpu->run->mmio.data);
+
+	ASSERT_EQ(byte_1, 0x12);
+	ASSERT_EQ(byte_2, 0x1234);
+	ASSERT_EQ(byte_4, 0x12345678);
+	ASSERT_EQ(byte_8, 0x1234567890ABCDEF);
+
+	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);
@@ -912,6 +996,7 @@ int main(int argc, char **argv)
 	run_in_new_process(&verify_guest_msr_reads);
 	run_in_new_process(&verify_guest_hlt);
 	run_in_new_process(&verify_mmio_reads);
+	run_in_new_process(&verify_mmio_writes);
 
 	return 0;
 }
-- 
2.39.0.246.g2a6d74b583-goog