// SPDX-License-Identifier: GPL-2.0
/*
 * KVM dirty page logging performance test
 *
 * Based on dirty_log_test.c
 *
 * Copyright (C) 2018, Red Hat, Inc.
 * Copyright (C) 2020, Google, Inc.
 */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <pthread.h>
#include <linux/bitmap.h>

#include "kvm_util.h"
#include "test_util.h"
#include "memstress.h"
#include "guest_modes.h"
#include "ucall_common.h"

/* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/
#define TEST_HOST_LOOP_N                2UL

static int nr_vcpus = 1;
static u64 guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
static bool run_vcpus_while_disabling_dirty_logging;

/* Host variables */
static u64 dirty_log_manual_caps;
static bool host_quit;
static int iteration;
static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];

static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
{
        struct kvm_vcpu *vcpu = vcpu_args->vcpu;
        int vcpu_idx = vcpu_args->vcpu_idx;
        u64 pages_count = 0;
        struct kvm_run *run;
        struct timespec start;
        struct timespec ts_diff;
        struct timespec total = (struct timespec){0};
        struct timespec avg;
        int ret;

        run = vcpu->run;

        while (!READ_ONCE(host_quit)) {
                int current_iteration = READ_ONCE(iteration);

                clock_gettime(CLOCK_MONOTONIC, &start);
                ret = _vcpu_run(vcpu);
                ts_diff = timespec_elapsed(start);

                TEST_ASSERT(ret == 0, "vcpu_run failed: %d", ret);
                TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC,
                            "Invalid guest sync status: exit_reason=%s",
                            exit_reason_str(run->exit_reason));

                pr_debug("Got sync event from vCPU %d\n", vcpu_idx);
                vcpu_last_completed_iteration[vcpu_idx] = current_iteration;
                pr_debug("vCPU %d updated last completed iteration to %d\n",
                         vcpu_idx, vcpu_last_completed_iteration[vcpu_idx]);

                if (current_iteration) {
                        pages_count += vcpu_args->pages;
                        total = timespec_add(total, ts_diff);
                        pr_debug("vCPU %d iteration %d dirty memory time: %ld.%.9lds\n",
                                vcpu_idx, current_iteration, ts_diff.tv_sec,
                                ts_diff.tv_nsec);
                } else {
                        pr_debug("vCPU %d iteration %d populate memory time: %ld.%.9lds\n",
                                vcpu_idx, current_iteration, ts_diff.tv_sec,
                                ts_diff.tv_nsec);
                }

                /*
                 * Keep running the guest while dirty logging is being disabled
                 * (iteration is negative) so that vCPUs are accessing memory
                 * for the entire duration of zapping collapsible SPTEs.
                 */
                while (current_iteration == READ_ONCE(iteration) &&
                       READ_ONCE(iteration) >= 0 && !READ_ONCE(host_quit)) {}
        }

        avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_idx]);
        pr_debug("\nvCPU %d dirtied 0x%lx pages over %d iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
                vcpu_idx, pages_count, vcpu_last_completed_iteration[vcpu_idx],
                total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
}

struct test_params {
        unsigned long iterations;
        u64 phys_offset;
        bool partition_vcpu_memory_access;
        enum vm_mem_backing_src_type backing_src;
        int slots;
        u32 write_percent;
        bool random_access;
};

static void run_test(enum vm_guest_mode mode, void *arg)
{
        struct test_params *p = arg;
        struct kvm_vm *vm;
        unsigned long **bitmaps;
        u64 guest_num_pages;
        u64 host_num_pages;
        u64 pages_per_slot;
        struct timespec start;
        struct timespec ts_diff;
        struct timespec get_dirty_log_total = (struct timespec){0};
        struct timespec vcpu_dirty_total = (struct timespec){0};
        struct timespec avg;
        struct timespec clear_dirty_log_total = (struct timespec){0};
        int i;

        vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
                                 p->slots, p->backing_src,
                                 p->partition_vcpu_memory_access);

        memstress_set_write_percent(vm, p->write_percent);

        guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift;
        guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
        host_num_pages = vm_num_host_pages(mode, guest_num_pages);
        pages_per_slot = host_num_pages / p->slots;

        bitmaps = memstress_alloc_bitmaps(p->slots, pages_per_slot);

        if (dirty_log_manual_caps)
                vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2,
                              dirty_log_manual_caps);

        /* Start the iterations */
        iteration = 0;
        host_quit = false;

        clock_gettime(CLOCK_MONOTONIC, &start);
        for (i = 0; i < nr_vcpus; i++)
                vcpu_last_completed_iteration[i] = -1;

        /*
         * Use 100% writes during the population phase to ensure all
         * memory is actually populated and not just mapped to the zero
         * page. The prevents expensive copy-on-write faults from
         * occurring during the dirty memory iterations below, which
         * would pollute the performance results.
         */
        memstress_set_write_percent(vm, 100);
        memstress_set_random_access(vm, false);
        memstress_start_vcpu_threads(nr_vcpus, vcpu_worker);

        /* Allow the vCPUs to populate memory */
        pr_debug("Starting iteration %d - Populating\n", iteration);
        for (i = 0; i < nr_vcpus; i++) {
                while (READ_ONCE(vcpu_last_completed_iteration[i]) !=
                       iteration)
                        ;
        }

        ts_diff = timespec_elapsed(start);
        pr_info("Populate memory time: %ld.%.9lds\n",
                ts_diff.tv_sec, ts_diff.tv_nsec);

        /* Enable dirty logging */
        clock_gettime(CLOCK_MONOTONIC, &start);
        memstress_enable_dirty_logging(vm, p->slots);
        ts_diff = timespec_elapsed(start);
        pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",
                ts_diff.tv_sec, ts_diff.tv_nsec);

        memstress_set_write_percent(vm, p->write_percent);
        memstress_set_random_access(vm, p->random_access);

        while (iteration < p->iterations) {
                /*
                 * Incrementing the iteration number will start the vCPUs
                 * dirtying memory again.
                 */
                clock_gettime(CLOCK_MONOTONIC, &start);
                iteration++;

                pr_debug("Starting iteration %d\n", iteration);
                for (i = 0; i < nr_vcpus; i++) {
                        while (READ_ONCE(vcpu_last_completed_iteration[i])
                               != iteration)
                                ;
                }

                ts_diff = timespec_elapsed(start);
                vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
                pr_info("Iteration %d dirty memory time: %ld.%.9lds\n",
                        iteration, ts_diff.tv_sec, ts_diff.tv_nsec);

                clock_gettime(CLOCK_MONOTONIC, &start);
                memstress_get_dirty_log(vm, bitmaps, p->slots);
                ts_diff = timespec_elapsed(start);
                get_dirty_log_total = timespec_add(get_dirty_log_total,
                                                   ts_diff);
                pr_info("Iteration %d get dirty log time: %ld.%.9lds\n",
                        iteration, ts_diff.tv_sec, ts_diff.tv_nsec);

                if (dirty_log_manual_caps) {
                        clock_gettime(CLOCK_MONOTONIC, &start);
                        memstress_clear_dirty_log(vm, bitmaps, p->slots,
                                                  pages_per_slot);
                        ts_diff = timespec_elapsed(start);
                        clear_dirty_log_total = timespec_add(clear_dirty_log_total,
                                                             ts_diff);
                        pr_info("Iteration %d clear dirty log time: %ld.%.9lds\n",
                                iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
                }
        }

        /*
         * Run vCPUs while dirty logging is being disabled to stress disabling
         * in terms of both performance and correctness.  Opt-in via command
         * line as this significantly increases time to disable dirty logging.
         */
        if (run_vcpus_while_disabling_dirty_logging)
                WRITE_ONCE(iteration, -1);

        /* Disable dirty logging */
        clock_gettime(CLOCK_MONOTONIC, &start);
        memstress_disable_dirty_logging(vm, p->slots);
        ts_diff = timespec_elapsed(start);
        pr_info("Disabling dirty logging time: %ld.%.9lds\n",
                ts_diff.tv_sec, ts_diff.tv_nsec);

        /*
         * Tell the vCPU threads to quit.  No need to manually check that vCPUs
         * have stopped running after disabling dirty logging, the join will
         * wait for them to exit.
         */
        host_quit = true;
        memstress_join_vcpu_threads(nr_vcpus);

        avg = timespec_div(get_dirty_log_total, p->iterations);
        pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
                p->iterations, get_dirty_log_total.tv_sec,
                get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);

        if (dirty_log_manual_caps) {
                avg = timespec_div(clear_dirty_log_total, p->iterations);
                pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
                        p->iterations, clear_dirty_log_total.tv_sec,
                        clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
        }

        memstress_free_bitmaps(bitmaps, p->slots);
        memstress_destroy_vm(vm);
}

static void help(char *name)
{
        puts("");
        printf("usage: %s [-h] [-a] [-i iterations] [-p offset] [-g] "
               "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-r random seed ] [-s mem type]"
               "[-x memslots] [-w percentage] [-c physical cpus to run test on]\n", name);
        puts("");
        printf(" -a: access memory randomly rather than in order.\n");
        printf(" -i: specify iteration counts (default: %"PRIu64")\n",
               TEST_HOST_LOOP_N);
        printf(" -g: Do not enable KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2. This\n"
               "     makes KVM_GET_DIRTY_LOG clear the dirty log (i.e.\n"
               "     KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is not enabled)\n"
               "     and writes will be tracked as soon as dirty logging is\n"
               "     enabled on the memslot (i.e. KVM_DIRTY_LOG_INITIALLY_SET\n"
               "     is not enabled).\n");
        printf(" -p: specify guest physical test memory offset\n"
               "     Warning: a low offset can conflict with the loaded test code.\n");
        guest_modes_help();
        printf(" -n: Run the vCPUs in nested mode (L2)\n");
        printf(" -e: Run vCPUs while dirty logging is being disabled.  This\n"
               "     can significantly increase runtime, especially if there\n"
               "     isn't a dedicated pCPU for the main thread.\n");
        printf(" -b: specify the size of the memory region which should be\n"
               "     dirtied by each vCPU. e.g. 10M or 3G.\n"
               "     (default: 1G)\n");
        printf(" -v: specify the number of vCPUs to run.\n");
        printf(" -o: Overlap guest memory accesses instead of partitioning\n"
               "     them into a separate region of memory for each vCPU.\n");
        printf(" -r: specify the starting random seed.\n");
        backing_src_help("-s");
        printf(" -x: Split the memory region into this number of memslots.\n"
               "     (default: 1)\n");
        printf(" -w: specify the percentage of pages which should be written to\n"
               "     as an integer from 0-100 inclusive. This is probabilistic,\n"
               "     so -w X means each page has an X%% chance of writing\n"
               "     and a (100-X)%% chance of reading.\n"
               "     (default: 100 i.e. all pages are written to.)\n");
        kvm_print_vcpu_pinning_help();
        puts("");
        exit(0);
}

int main(int argc, char *argv[])
{
        int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
        const char *pcpu_list = NULL;
        struct test_params p = {
                .iterations = TEST_HOST_LOOP_N,
                .partition_vcpu_memory_access = true,
                .backing_src = DEFAULT_VM_MEM_SRC,
                .slots = 1,
                .write_percent = 100,
        };
        int opt;

        /* Override the seed to be deterministic by default. */
        guest_random_seed = 1;

        dirty_log_manual_caps =
                kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
        dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
                                  KVM_DIRTY_LOG_INITIALLY_SET);

        guest_modes_append_default();

        while ((opt = getopt(argc, argv, "ab:c:eghi:m:nop:r:s:v:x:w:")) != -1) {
                switch (opt) {
                case 'a':
                        p.random_access = true;
                        break;
                case 'b':
                        guest_percpu_mem_size = parse_size(optarg);
                        break;
                case 'c':
                        pcpu_list = optarg;
                        break;
                case 'e':
                        /* 'e' is for evil. */
                        run_vcpus_while_disabling_dirty_logging = true;
                        break;
                case 'g':
                        dirty_log_manual_caps = 0;
                        break;
                case 'h':
                        help(argv[0]);
                        break;
                case 'i':
                        p.iterations = atoi_positive("Number of iterations", optarg);
                        break;
                case 'm':
                        guest_modes_cmdline(optarg);
                        break;
                case 'n':
                        memstress_args.nested = true;
                        break;
                case 'o':
                        p.partition_vcpu_memory_access = false;
                        break;
                case 'p':
                        p.phys_offset = strtoull(optarg, NULL, 0);
                        break;
                case 'r':
                        guest_random_seed = atoi_positive("Random seed", optarg);
                        break;
                case 's':
                        p.backing_src = parse_backing_src_type(optarg);
                        break;
                case 'v':
                        nr_vcpus = atoi_positive("Number of vCPUs", optarg);
                        TEST_ASSERT(nr_vcpus <= max_vcpus,
                                    "Invalid number of vcpus, must be between 1 and %d", max_vcpus);
                        break;
                case 'w':
                        p.write_percent = atoi_non_negative("Write percentage", optarg);
                        TEST_ASSERT(p.write_percent <= 100,
                                    "Write percentage must be between 0 and 100");
                        break;
                case 'x':
                        p.slots = atoi_positive("Number of slots", optarg);
                        break;
                default:
                        help(argv[0]);
                        break;
                }
        }

        if (pcpu_list) {
                kvm_parse_vcpu_pinning(pcpu_list, memstress_args.vcpu_to_pcpu,
                                       nr_vcpus);
                memstress_args.pin_vcpus = true;
        }

        TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations");

        pr_info("Test iterations: %"PRIu64"\n", p.iterations);

        for_each_guest_mode(run_test, &p);

        return 0;
}