selftests: KVM: Test SYSTEM_SUSPEND PSCI call

Assert that the vCPU exits to userspace with KVM_SYSTEM_EVENT_SUSPEND if
the guest calls PSCI SYSTEM_SUSPEND. Additionally, guarantee that the
SMC32 and SMC64 flavors of this call are discoverable with the
PSCI_FEATURES call.
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220504032446.4133305-13-oupton@google.com

tools/testing/selftests/kvm/aarch64/psci_test.c

@@ -45,6 +45,25 @@ static uint64_t psci_affinity_info(uint64_t target_affinity,
 	return res.a0;
 }
 
+static uint64_t psci_system_suspend(uint64_t entry_addr, uint64_t context_id)
+{
+	struct arm_smccc_res res;
+
+	smccc_hvc(PSCI_1_0_FN64_SYSTEM_SUSPEND, entry_addr, context_id,
+		  0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+static uint64_t psci_features(uint32_t func_id)
+{
+	struct arm_smccc_res res;
+
+	smccc_hvc(PSCI_1_0_FN_PSCI_FEATURES, func_id, 0, 0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
 static void vcpu_power_off(struct kvm_vm *vm, uint32_t vcpuid)
 {
 	struct kvm_mp_state mp_state = {
@@ -137,8 +156,58 @@ static void host_test_cpu_on(void)
 	kvm_vm_free(vm);
 }
 
+static void enable_system_suspend(struct kvm_vm *vm)
+{
+	struct kvm_enable_cap cap = {
+		.cap = KVM_CAP_ARM_SYSTEM_SUSPEND,
+	};
+
+	vm_enable_cap(vm, &cap);
+}
+
+static void guest_test_system_suspend(void)
+{
+	uint64_t ret;
+
+	/* assert that SYSTEM_SUSPEND is discoverable */
+	GUEST_ASSERT(!psci_features(PSCI_1_0_FN_SYSTEM_SUSPEND));
+	GUEST_ASSERT(!psci_features(PSCI_1_0_FN64_SYSTEM_SUSPEND));
+
+	ret = psci_system_suspend(CPU_ON_ENTRY_ADDR, CPU_ON_CONTEXT_ID);
+	GUEST_SYNC(ret);
+}
+
+static void host_test_system_suspend(void)
+{
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+
+	vm = setup_vm(guest_test_system_suspend);
+	enable_system_suspend(vm);
+
+	vcpu_power_off(vm, VCPU_ID_TARGET);
+	run = vcpu_state(vm, VCPU_ID_SOURCE);
+
+	enter_guest(vm, VCPU_ID_SOURCE);
+
+	TEST_ASSERT(run->exit_reason == KVM_EXIT_SYSTEM_EVENT,
+		    "Unhandled exit reason: %u (%s)",
+		    run->exit_reason, exit_reason_str(run->exit_reason));
+	TEST_ASSERT(run->system_event.type == KVM_SYSTEM_EVENT_SUSPEND,
+		    "Unhandled system event: %u (expected: %u)",
+		    run->system_event.type, KVM_SYSTEM_EVENT_SUSPEND);
+
+	kvm_vm_free(vm);
+}
+
 int main(void)
 {
+	if (!kvm_check_cap(KVM_CAP_ARM_SYSTEM_SUSPEND)) {
+		print_skip("KVM_CAP_ARM_SYSTEM_SUSPEND not supported");
+		exit(KSFT_SKIP);
+	}
+
 	host_test_cpu_on();
+	host_test_system_suspend();
 	return 0;
 }