// SPDX-License-Identifier: GPL-2.0-only
/*
 * arch_timer.c - Tests the arch timer IRQ functionality
 *
 * The guest's main thread configures the timer interrupt and waits
 * for it to fire, with a timeout equal to the timer period.
 * It asserts that the timeout doesn't exceed the timer period plus
 * a user configurable error margin(default to 100us)
 *
 * On the other hand, upon receipt of an interrupt, the guest's interrupt
 * handler validates the interrupt by checking if the architectural state
 * is in compliance with the specifications.
 *
 * The test provides command-line options to configure the timer's
 * period (-p), number of vCPUs (-n), iterations per stage (-i) and timer
 * interrupt arrival error margin (-e). To stress-test the timer stack
 * even more, an option to migrate the vCPUs across pCPUs (-m), at a
 * particular rate, is also provided.
 *
 * Copyright (c) 2021, Google LLC.
 */
#include <stdlib.h>
#include <pthread.h>
#include <linux/sizes.h>
#include <linux/bitmap.h>
#include <sys/sysinfo.h>

#include "timer_test.h"
#include "ucall_common.h"

struct test_args test_args = {
        .nr_vcpus = NR_VCPUS_DEF,
        .nr_iter = NR_TEST_ITERS_DEF,
        .timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
        .migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
        .timer_err_margin_us = TIMER_TEST_ERR_MARGIN_US,
        .reserved = 1,
};

struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];

static pthread_t pt_vcpu_run[KVM_MAX_VCPUS];
static unsigned long *vcpu_done_map;
static pthread_mutex_t vcpu_done_map_lock;

static void *test_vcpu_run(void *arg)
{
        unsigned int vcpu_idx = (unsigned long)arg;
        struct ucall uc;
        struct kvm_vcpu *vcpu = vcpus[vcpu_idx];
        struct kvm_vm *vm = vcpu->vm;
        struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpu_idx];

        vcpu_run(vcpu);

        /* Currently, any exit from guest is an indication of completion */
        pthread_mutex_lock(&vcpu_done_map_lock);
        __set_bit(vcpu_idx, vcpu_done_map);
        pthread_mutex_unlock(&vcpu_done_map_lock);

        switch (get_ucall(vcpu, &uc)) {
        case UCALL_SYNC:
        case UCALL_DONE:
                break;
        case UCALL_ABORT:
                sync_global_from_guest(vm, *shared_data);
                fprintf(stderr, "Guest assert failed,  vcpu %u; stage; %u; iter: %u\n",
                        vcpu_idx, shared_data->guest_stage, shared_data->nr_iter);
                REPORT_GUEST_ASSERT(uc);
                break;
        default:
                TEST_FAIL("Unexpected guest exit");
        }

        pr_info("PASS(vCPU-%d).\n", vcpu_idx);

        return NULL;
}

static uint32_t test_get_pcpu(void)
{
        uint32_t pcpu;
        unsigned int nproc_conf;
        cpu_set_t online_cpuset;

        nproc_conf = get_nprocs_conf();
        sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset);

        /* Randomly find an available pCPU to place a vCPU on */
        do {
                pcpu = rand() % nproc_conf;
        } while (!CPU_ISSET(pcpu, &online_cpuset));

        return pcpu;
}

static int test_migrate_vcpu(unsigned int vcpu_idx)
{
        int ret;
        uint32_t new_pcpu = test_get_pcpu();

        pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu_idx, new_pcpu);

        ret = __pin_task_to_cpu(pt_vcpu_run[vcpu_idx], new_pcpu);

        /* Allow the error where the vCPU thread is already finished */
        TEST_ASSERT(ret == 0 || ret == ESRCH,
                    "Failed to migrate the vCPU:%u to pCPU: %u; ret: %d",
                    vcpu_idx, new_pcpu, ret);

        return ret;
}

static void *test_vcpu_migration(void *arg)
{
        unsigned int i, n_done;
        bool vcpu_done;

        do {
                usleep(msecs_to_usecs(test_args.migration_freq_ms));

                for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) {
                        pthread_mutex_lock(&vcpu_done_map_lock);
                        vcpu_done = test_bit(i, vcpu_done_map);
                        pthread_mutex_unlock(&vcpu_done_map_lock);

                        if (vcpu_done) {
                                n_done++;
                                continue;
                        }

                        test_migrate_vcpu(i);
                }
        } while (test_args.nr_vcpus != n_done);

        return NULL;
}

static void test_run(struct kvm_vm *vm)
{
        pthread_t pt_vcpu_migration;
        unsigned int i;
        int ret;

        pthread_mutex_init(&vcpu_done_map_lock, NULL);
        vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus);
        TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap");

        for (i = 0; i < (unsigned long)test_args.nr_vcpus; i++) {
                ret = pthread_create(&pt_vcpu_run[i], NULL, test_vcpu_run,
                                     (void *)(unsigned long)i);
                TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread", i);
        }

        /* Spawn a thread to control the vCPU migrations */
        if (test_args.migration_freq_ms) {
                srand(time(NULL));

                ret = pthread_create(&pt_vcpu_migration, NULL,
                                        test_vcpu_migration, NULL);
                TEST_ASSERT(!ret, "Failed to create the migration pthread");
        }


        for (i = 0; i < test_args.nr_vcpus; i++)
                pthread_join(pt_vcpu_run[i], NULL);

        if (test_args.migration_freq_ms)
                pthread_join(pt_vcpu_migration, NULL);

        bitmap_free(vcpu_done_map);
}

static void test_print_help(char *name)
{
        pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\n"
                "\t\t    [-m migration_freq_ms] [-o counter_offset]\n"
                "\t\t    [-e timer_err_margin_us]\n", name);
        pr_info("\t-n: Number of vCPUs to configure (default: %u; max: %u)\n",
                NR_VCPUS_DEF, KVM_MAX_VCPUS);
        pr_info("\t-i: Number of iterations per stage (default: %u)\n",
                NR_TEST_ITERS_DEF);
        pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n",
                TIMER_TEST_PERIOD_MS_DEF);
        pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
                TIMER_TEST_MIGRATION_FREQ_MS);
        pr_info("\t-o: Counter offset (in counter cycles, default: 0) [aarch64-only]\n");
        pr_info("\t-e: Interrupt arrival error margin (in us) of the guest timer (default: %u)\n",
                TIMER_TEST_ERR_MARGIN_US);
        pr_info("\t-h: print this help screen\n");
}

static bool parse_args(int argc, char *argv[])
{
        int opt;

        while ((opt = getopt(argc, argv, "hn:i:p:m:o:e:")) != -1) {
                switch (opt) {
                case 'n':
                        test_args.nr_vcpus = atoi_positive("Number of vCPUs", optarg);
                        if (test_args.nr_vcpus > KVM_MAX_VCPUS) {
                                pr_info("Max allowed vCPUs: %u\n",
                                        KVM_MAX_VCPUS);
                                goto err;
                        }
                        break;
                case 'i':
                        test_args.nr_iter = atoi_positive("Number of iterations", optarg);
                        break;
                case 'p':
                        test_args.timer_period_ms = atoi_positive("Periodicity", optarg);
                        break;
                case 'm':
                        test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg);
                        break;
                case 'e':
                        test_args.timer_err_margin_us = atoi_non_negative("Error Margin", optarg);
                        break;
                case 'o':
                        test_args.counter_offset = strtol(optarg, NULL, 0);
                        test_args.reserved = 0;
                        break;
                case 'h':
                default:
                        goto err;
                }
        }

        return true;

err:
        test_print_help(argv[0]);
        return false;
}

int main(int argc, char *argv[])
{
        struct kvm_vm *vm;

        if (!parse_args(argc, argv))
                exit(KSFT_SKIP);

        __TEST_REQUIRE(!test_args.migration_freq_ms || get_nprocs() >= 2,
                       "At least two physical CPUs needed for vCPU migration");

        vm = test_vm_create();
        test_run(vm);
        test_vm_cleanup(vm);

        return 0;
}