/*
 * Copyright 2018 The Hafnium Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdalign.h>
#include <stdint.h>

#include "hf/arch/vm/power_mgmt.h"

#include "hf/assert.h"
#include "hf/mm.h"
#include "hf/std.h"

#include "vmapi/hf/call.h"

#include "hftest.h"
#include "primary_with_secondary.h"
#include "util.h"

/**
 * Iterates trying to run vCPU of the secondary VM. Returns when a message
 * of non-zero length is received.
 */
static bool run_loop(struct mailbox_buffers *mb)
{
	struct hf_vcpu_run_return run_res;
	bool ok = false;

	for (;;) {
		/* Run until it manages to schedule vCPU on this CPU. */
		do {
			run_res = hf_vcpu_run(SERVICE_VM0, 0);
		} while (run_res.code == HF_VCPU_RUN_WAIT_FOR_INTERRUPT &&
			 run_res.sleep.ns == HF_SLEEP_INDEFINITE);

		/* Break out if we received a message with non-zero length. */
		if (run_res.code == HF_VCPU_RUN_MESSAGE &&
		    mb->recv->length != 0) {
			break;
		}

		/* Clear mailbox so that next message can be received. */
		hf_mailbox_clear();
	}

	/* Copies the contents of the received boolean to the return value. */
	if (mb->recv->length == sizeof(ok)) {
		ok = *(bool *)mb->recv->payload;
	}

	hf_mailbox_clear();

	return ok;
}

/**
 * This is the entry point of the additional primary VM vCPU. It just calls
 * the run loop so that two cpus compete for the chance to run a secondary VM.
 */
static void vm_cpu_entry(uintptr_t arg)
{
	run_loop((struct mailbox_buffers *)arg);
}

/**
 * This test tries to run the same secondary vCPU from two different physical
 * CPUs concurrently. The vCPU checks that the state is ok while it bounces
 * between the physical CPUs.
 */
TEST(vcpu_state, concurrent_save_restore)
{
	alignas(4096) static char stack[4096];
	static struct mailbox_buffers mb;

	mb = set_up_mailbox();

	SERVICE_SELECT(SERVICE_VM0, "check_state", mb.send);

	/* Start second vCPU. */
	ASSERT_TRUE(cpu_start(hftest_get_cpu_id(1), stack, sizeof(stack),
			      vm_cpu_entry, (uintptr_t)&mb));

	/* Run on a loop until the secondary VM is done. */
	EXPECT_TRUE(run_loop(&mb));
}