[RFC PATCH v3 14/31] KVM: selftests: TDX: Add TDX IO writes test

Ackerley Tng
2023-01-21T00:17:55Z

From: Sagi Shahar <sagis@google.com>

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

Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
.../selftests/kvm/include/x86_64/tdx/tdcall.h | 3 +
.../selftests/kvm/x86_64/tdx_vm_tests.c | 91 +++++++++++++++++++
2 files changed, 94 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
index 78001bfec9c8d..b5e94b7c48fa5 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
@@ -10,6 +10,9 @@
#define TDG_VP_VMCALL_INSTRUCTION_IO_READ 0
#define TDG_VP_VMCALL_INSTRUCTION_IO_WRITE 1

+#define TDG_VP_VMCALL_SUCCESS 0x0000000000000000
+#define TDG_VP_VMCALL_INVALID_OPERAND 0x8000000000000000
+
#define TDX_HCALL_HAS_OUTPUT BIT(0)

#define TDX_HYPERCALL_STANDARD 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 188442a734dca..ac23d1ad1e687 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -338,6 +338,96 @@ void verify_get_td_vmcall_info(void)
printf("\t ... PASSED\n");
}

+#define TDX_IO_WRITES_TEST_PORT 0x51
+
+/*
+ * Verifies IO functionality by writing values of different sizes
+ * to the host.
+ */
+void guest_io_writes(void)
+{
+ uint64_t byte_1 = 0xAB;
+ uint64_t byte_2 = 0xABCD;
+ uint64_t byte_4 = 0xFFABCDEF;
+ uint64_t ret;
+
+ ret = tdg_vp_vmcall_instruction_io(TDX_IO_WRITES_TEST_PORT, 1,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+ &byte_1);
+ if (ret)
+ tdx_test_fatal(ret);
+
+ ret = tdg_vp_vmcall_instruction_io(TDX_IO_WRITES_TEST_PORT, 2,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+ &byte_2);
+ if (ret)
+ tdx_test_fatal(ret);
+
+ ret = tdg_vp_vmcall_instruction_io(TDX_IO_WRITES_TEST_PORT, 4,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+ &byte_4);
+ if (ret)
+ tdx_test_fatal(ret);
+
+ // Write an invalid number of bytes.
+ ret = tdg_vp_vmcall_instruction_io(TDX_IO_WRITES_TEST_PORT, 5,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+ &byte_4);
+ if (ret)
+ tdx_test_fatal(ret);
+
+ tdx_test_success();
+}
+
+void verify_guest_writes(void)
+{
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+
+ uint8_t byte_1;
+ uint16_t byte_2;
+ uint32_t byte_4;
+
+ vm = td_create();
+ td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+ vcpu = td_vcpu_add(vm, 0, guest_io_writes);
+ td_finalize(vm);
+
+ printf("Verifying guest writes:\n");
+
+ vcpu_run(vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_IO_WRITES_TEST_PORT, 1,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ byte_1 = *(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+ vcpu_run(vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_IO_WRITES_TEST_PORT, 2,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ byte_2 = *(uint16_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+ vcpu_run(vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_IO_WRITES_TEST_PORT, 4,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ byte_4 = *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+ ASSERT_EQ(byte_1, 0xAB);
+ ASSERT_EQ(byte_2, 0xABCD);
+ ASSERT_EQ(byte_4, 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);
@@ -352,6 +442,7 @@ int main(int argc, char **argv)
run_in_new_process(&verify_td_ioexit);
run_in_new_process(&verify_td_cpuid);
run_in_new_process(&verify_get_td_vmcall_info);
+ run_in_new_process(&verify_guest_writes);

return 0;
}
--
2.39.0.246.g2a6d74b583-goog