[RFC PATCH v5 16/29] KVM: selftests: TDX: Add TDX HLT exit test

[Sagi Shahar <sagis@google.com>]

The test verifies that the guest runs TDVMCALL<INSTRUCTION.HLT> and the
guest vCPU enters to the halted state.

Signed-off-by: Erdem Aktas <erdemaktas@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ryan Afranji <afranji@google.com>
---
 .../selftests/kvm/include/x86_64/tdx/tdx.h    |  2 +
 .../selftests/kvm/lib/x86_64/tdx/tdx.c        | 10 +++
 .../selftests/kvm/x86_64/tdx_vm_tests.c       | 78 +++++++++++++++++++
 3 files changed, 90 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 85ba6aab79a7..b18e39d20498 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
@@ -8,6 +8,7 @@
 #define TDG_VP_VMCALL_GET_TD_VM_CALL_INFO 0x10000
 #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
 
+#define TDG_VP_VMCALL_INSTRUCTION_HLT 12
 #define TDG_VP_VMCALL_INSTRUCTION_IO 30
 #define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
 #define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
@@ -20,5 +21,6 @@ uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
 					uint64_t *r13, uint64_t *r14);
 uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value);
 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);
 
 #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 88ea6f2a6469..9485bafedc38 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -114,3 +114,13 @@ uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value)
 
 	return __tdx_hypercall(&args, 0);
 }
+
+uint64_t tdg_vp_vmcall_instruction_hlt(uint64_t interrupt_blocked_flag)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_INSTRUCTION_HLT,
+		.r12 = interrupt_blocked_flag,
+	};
+
+	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 5db3701cc6d9..5fae4c6e5f95 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -721,6 +721,83 @@ void verify_guest_msr_writes(void)
 	printf("\t ... PASSED\n");
 }
 
+/*
+ * Verifies HLT functionality.
+ */
+void guest_hlt(void)
+{
+	uint64_t ret;
+	uint64_t interrupt_blocked_flag;
+
+	interrupt_blocked_flag = 0;
+	ret = tdg_vp_vmcall_instruction_hlt(interrupt_blocked_flag);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	tdx_test_success();
+}
+
+void _verify_guest_hlt(int signum);
+
+void wake_me(int interval)
+{
+	struct sigaction action;
+
+	action.sa_handler = _verify_guest_hlt;
+	sigemptyset(&action.sa_mask);
+	action.sa_flags = 0;
+
+	TEST_ASSERT(sigaction(SIGALRM, &action, NULL) == 0,
+		    "Could not set the alarm handler!");
+
+	alarm(interval);
+}
+
+void _verify_guest_hlt(int signum)
+{
+	struct kvm_vm *vm;
+	static struct kvm_vcpu *vcpu;
+
+	/*
+	 * This function will also be called by SIGALRM handler to check the
+	 * vCPU MP State. If vm has been initialized, then we are in the signal
+	 * handler. Check the MP state and let the guest run again.
+	 */
+	if (vcpu != NULL) {
+		struct kvm_mp_state mp_state;
+
+		vcpu_mp_state_get(vcpu, &mp_state);
+		TEST_ASSERT_EQ(mp_state.mp_state, KVM_MP_STATE_HALTED);
+
+		/* Let the guest to run and finish the test.*/
+		mp_state.mp_state = KVM_MP_STATE_RUNNABLE;
+		vcpu_mp_state_set(vcpu, &mp_state);
+		return;
+	}
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_hlt);
+	td_finalize(vm);
+
+	printf("Verifying HLT:\n");
+
+	printf("\t ... Running guest\n");
+
+	/* Wait 1 second for guest to execute HLT */
+	wake_me(1);
+	td_vcpu_run(vcpu);
+
+	TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
+void verify_guest_hlt(void)
+{
+	_verify_guest_hlt(0);
+}
 
 int main(int argc, char **argv)
 {
@@ -740,6 +817,7 @@ int main(int argc, char **argv)
 	run_in_new_process(&verify_guest_reads);
 	run_in_new_process(&verify_guest_msr_writes);
 	run_in_new_process(&verify_guest_msr_reads);
+	run_in_new_process(&verify_guest_hlt);
 
 	return 0;
 }
-- 
2.43.0.472.g3155946c3a-goog