Re: [RFC PATCH v5 18/29] KVM: selftests: TDX: Add TDX MMIO writes test

Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> · Sat, 2 Mar 2024 15:58:07 +0800

On 12/13/2023 4:46 AM, Sagi Shahar wrote:
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>
Signed-off-by: Ryan Afranji <afranji@xxxxxxxxxx>

Patch 17 and 18 test the part that guest has received the #VE caused by
MMIO access, so calls the td vmcall to kvm to do the emulation.

Should the generation of #VE due to MMIO access be covered as well?

---
  .../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 13ce60df5684..502b670ea699 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/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_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
index b19f07ebc0e7..f4afa09f7e3d 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -143,3 +143,17 @@ 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 48902b69d13e..5e28ba828a92 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -885,6 +885,90 @@ 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");
+
+	td_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);
+
+	td_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);
+
+	td_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);
+
+	td_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);
+
+	TEST_ASSERT_EQ(byte_1, 0x12);
+	TEST_ASSERT_EQ(byte_2, 0x1234);
+	TEST_ASSERT_EQ(byte_4, 0x12345678);
+	TEST_ASSERT_EQ(byte_8, 0x1234567890ABCDEF);
+
+	td_vcpu_run(vcpu);
+	TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
+	TEST_ASSERT_EQ(vcpu->run->system_event.data[1], TDG_VP_VMCALL_INVALID_OPERAND);
+
+	td_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);
@@ -905,6 +989,7 @@ 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;
  }








