[PATCH v8 13/30] KVM: selftests: TDX: Add basic TDG.VP.VMCALL<GetTdVmCallInfo> test

[Sagi Shahar <sagis@google.com>]

The test calls TDG.VP.VMCALL<GetTdVmCallInfo> hypercall from the guest
and verifies the expected returned values.

TDG.VP.VMCALL<GetTdVmCallInfo> hypercall is a subleaf of TDG.VP.VMCALL to
enumerate which TDG.VP.VMCALL sub leaves are supported.  This hypercall is
for future enhancement of the Guest-Host-Communication Interface (GHCI)
specification. The GHCI version of 344426-001US defines it to require
input R12 to be zero and to return zero in output registers, R11, R12, R13,
and R14 so that guest TD enumerates no enhancement.

Signed-off-by: Sagi Shahar <sagis@google.com>
---
 .../selftests/kvm/include/x86/tdx/tdx.h       |  3 +
 .../selftests/kvm/include/x86/tdx/test_util.h | 27 +++++++
 tools/testing/selftests/kvm/lib/x86/tdx/tdx.c | 23 ++++++
 .../selftests/kvm/lib/x86/tdx/test_util.c     | 42 +++++++++++
 tools/testing/selftests/kvm/x86/tdx_vm_test.c | 72 ++++++++++++++++++-
 5 files changed, 166 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 2acccc9dccf9..97ceb90c8792 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
@@ -6,6 +6,7 @@
 
 #include "kvm_util.h"
 
+#define TDG_VP_VMCALL_GET_TD_VM_CALL_INFO 0x10000
 #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
 
 #define TDG_VP_VMCALL_INSTRUCTION_IO 30
@@ -13,4 +14,6 @@
 uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
 				      uint64_t write, uint64_t *data);
 void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa);
+uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
+					  uint64_t *r13, uint64_t *r14);
 #endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
index 2af6e810ef78..91031e956462 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
@@ -4,6 +4,7 @@
 
 #include <stdbool.h>
 
+#include "kvm_util.h"
 #include "tdcall.h"
 
 #define TDX_TEST_SUCCESS_PORT 0x30
@@ -92,4 +93,30 @@ uint64_t tdx_test_report_to_user_space(uint32_t data);
  */
 uint32_t tdx_test_read_report_from_guest(struct kvm_vcpu *vcpu);
 
+/*
+ * Report a 64 bit value from the guest to user space using TDG.VP.VMCALL
+ * <Instruction.IO> call.
+ *
+ * Data is sent to host in 2 calls. LSB is sent (and needs to be read) first.
+ */
+uint64_t tdx_test_send_64bit(uint64_t port, uint64_t data);
+
+/*
+ * Report a 64 bit value from the guest to user space using TDG.VP.VMCALL
+ * <Instruction.IO> call. Data is reported on port TDX_TEST_REPORT_PORT.
+ */
+uint64_t tdx_test_report_64bit_to_user_space(uint64_t data);
+
+/*
+ * Read a 64 bit value from the guest in user space, sent using
+ * tdx_test_send_64bit().
+ */
+uint64_t tdx_test_read_64bit(struct kvm_vcpu *vcpu, uint64_t port);
+
+/*
+ * Read a 64 bit value from the guest in user space, sent using
+ * tdx_test_report_64bit_to_user_space().
+ */
+uint64_t tdx_test_read_64bit_report_from_guest(struct kvm_vcpu *vcpu);
+
 #endif // SELFTEST_TDX_TEST_UTIL_H
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
index ba088bfc1e62..5105dfae0e9e 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
@@ -43,3 +43,26 @@ void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa)
 
 	__tdx_hypercall(&args, 0);
 }
+
+uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
+					  uint64_t *r13, uint64_t *r14)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_GET_TD_VM_CALL_INFO,
+		.r12 = 0,
+	};
+	uint64_t ret;
+
+	ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+	if (r11)
+		*r11 = args.r11;
+	if (r12)
+		*r12 = args.r12;
+	if (r13)
+		*r13 = args.r13;
+	if (r14)
+		*r14 = args.r14;
+
+	return ret;
+}
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
index f9bde114a8bc..8c3b6802c37e 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
@@ -7,6 +7,7 @@
 #include <unistd.h>
 
 #include "kvm_util.h"
+#include "tdx/tdcall.h"
 #include "tdx/tdx.h"
 #include "tdx/tdx_util.h"
 #include "tdx/test_util.h"
@@ -124,3 +125,44 @@ uint32_t tdx_test_read_report_from_guest(struct kvm_vcpu *vcpu)
 
 	return res;
 }
+
+uint64_t tdx_test_send_64bit(uint64_t port, uint64_t data)
+{
+	uint64_t data_hi = (data >> 32) & 0xFFFFFFFF;
+	uint64_t data_lo = data & 0xFFFFFFFF;
+	uint64_t err;
+
+	err = tdg_vp_vmcall_instruction_io(port, 4, PORT_WRITE, &data_lo);
+	if (err)
+		return err;
+
+	return tdg_vp_vmcall_instruction_io(port, 4, PORT_WRITE, &data_hi);
+}
+
+uint64_t tdx_test_report_64bit_to_user_space(uint64_t data)
+{
+	return tdx_test_send_64bit(TDX_TEST_REPORT_PORT, data);
+}
+
+uint64_t tdx_test_read_64bit(struct kvm_vcpu *vcpu, uint64_t port)
+{
+	uint32_t lo, hi;
+	uint64_t res;
+
+	tdx_test_assert_io(vcpu, port, 4, PORT_WRITE);
+	lo = *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+	vcpu_run(vcpu);
+
+	tdx_test_assert_io(vcpu, port, 4, PORT_WRITE);
+	hi = *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+	res = hi;
+	res = (res << 32) | lo;
+	return res;
+}
+
+uint64_t tdx_test_read_64bit_report_from_guest(struct kvm_vcpu *vcpu)
+{
+	return tdx_test_read_64bit(vcpu, TDX_TEST_REPORT_PORT);
+}
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
index bbdcca358d71..22143d16e0d1 100644
--- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c
+++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
@@ -240,6 +240,74 @@ void verify_td_cpuid(void)
 	printf("\t ... PASSED\n");
 }
 
+/*
+ * Verifies TDG.VP.VMCALL<GetTdVmCallInfo> hypercall functionality.
+ */
+void guest_code_get_td_vmcall_info(void)
+{
+	uint64_t r11, r12, r13, r14;
+	uint64_t err;
+
+	err = tdg_vp_vmcall_get_td_vmcall_info(&r11, &r12, &r13, &r14);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_64bit_to_user_space(r11);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_64bit_to_user_space(r12);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_64bit_to_user_space(r13);
+	tdx_assert_error(err);
+
+	err = tdx_test_report_64bit_to_user_space(r14);
+	tdx_assert_error(err);
+
+	tdx_test_success();
+}
+
+void verify_get_td_vmcall_info(void)
+{
+	uint64_t r11, r12, r13, r14;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_code_get_td_vmcall_info);
+	td_finalize(vm);
+
+	printf("Verifying TD get vmcall info:\n");
+
+	/* Wait for guest to report r11 value */
+	tdx_run(vcpu);
+	r11 = tdx_test_read_64bit_report_from_guest(vcpu);
+
+	/* Wait for guest to report r12 value */
+	tdx_run(vcpu);
+	r12 = tdx_test_read_64bit_report_from_guest(vcpu);
+
+	/* Wait for guest to report r13 value */
+	tdx_run(vcpu);
+	r13 = tdx_test_read_64bit_report_from_guest(vcpu);
+
+	/* Wait for guest to report r14 value */
+	tdx_run(vcpu);
+	r14 = tdx_test_read_64bit_report_from_guest(vcpu);
+
+	TEST_ASSERT_EQ(r11, 0);
+	TEST_ASSERT_EQ(r12, 0);
+	TEST_ASSERT_EQ(r13, 0);
+	TEST_ASSERT_EQ(r14, 0);
+
+	/* Wait for guest to complete execution */
+	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();
@@ -247,7 +315,7 @@ 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(4);
+	ksft_set_plan(5);
 	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),
@@ -256,6 +324,8 @@ int main(int argc, char **argv)
 			 "verify_td_ioexit\n");
 	ksft_test_result(!run_in_new_process(&verify_td_cpuid),
 			 "verify_td_cpuid\n");
+	ksft_test_result(!run_in_new_process(&verify_get_td_vmcall_info),
+			 "verify_get_td_vmcall_info\n");
 
 	ksft_finished();
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog