--- /dev/null
+// 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.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+#include <pthread.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+
+#include "kvm_util.h"
+#include "perf_test_util.h"
+#include "processor.h"
+#include "test_util.h"
+
+/* How many host loops to run by default (one KVM_GET_DIRTY_LOG for each loop)*/
+#define TEST_HOST_LOOP_N               2UL
+
+/* Host variables */
+static bool host_quit;
+static uint64_t iteration;
+static uint64_t vcpu_last_completed_iteration[MAX_VCPUS];
+
+static void *vcpu_worker(void *data)
+{
+       int ret;
+       struct kvm_vm *vm = perf_test_args.vm;
+       uint64_t pages_count = 0;
+       struct kvm_run *run;
+       struct timespec start;
+       struct timespec ts_diff;
+       struct timespec total = (struct timespec){0};
+       struct timespec avg;
+       struct vcpu_args *vcpu_args = (struct vcpu_args *)data;
+       int vcpu_id = vcpu_args->vcpu_id;
+
+       vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
+       run = vcpu_state(vm, vcpu_id);
+
+       while (!READ_ONCE(host_quit)) {
+               uint64_t current_iteration = READ_ONCE(iteration);
+
+               clock_gettime(CLOCK_MONOTONIC, &start);
+               ret = _vcpu_run(vm, vcpu_id);
+               ts_diff = timespec_diff_now(start);
+
+               TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
+               TEST_ASSERT(get_ucall(vm, vcpu_id, NULL) == UCALL_SYNC,
+                           "Invalid guest sync status: exit_reason=%s\n",
+                           exit_reason_str(run->exit_reason));
+
+               pr_debug("Got sync event from vCPU %d\n", vcpu_id);
+               vcpu_last_completed_iteration[vcpu_id] = current_iteration;
+               pr_debug("vCPU %d updated last completed iteration to %lu\n",
+                        vcpu_id, vcpu_last_completed_iteration[vcpu_id]);
+
+               if (current_iteration) {
+                       pages_count += vcpu_args->pages;
+                       total = timespec_add(total, ts_diff);
+                       pr_debug("vCPU %d iteration %lu dirty memory time: %ld.%.9lds\n",
+                               vcpu_id, current_iteration, ts_diff.tv_sec,
+                               ts_diff.tv_nsec);
+               } else {
+                       pr_debug("vCPU %d iteration %lu populate memory time: %ld.%.9lds\n",
+                               vcpu_id, current_iteration, ts_diff.tv_sec,
+                               ts_diff.tv_nsec);
+               }
+
+               while (current_iteration == READ_ONCE(iteration) &&
+                      !READ_ONCE(host_quit)) {}
+       }
+
+       avg = timespec_div(total, vcpu_last_completed_iteration[vcpu_id]);
+       pr_debug("\nvCPU %d dirtied 0x%lx pages over %lu iterations in %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
+               vcpu_id, pages_count, vcpu_last_completed_iteration[vcpu_id],
+               total.tv_sec, total.tv_nsec, avg.tv_sec, avg.tv_nsec);
+
+       return NULL;
+}
+
+#ifdef USE_CLEAR_DIRTY_LOG
+static u64 dirty_log_manual_caps;
+#endif
+
+static void run_test(enum vm_guest_mode mode, unsigned long iterations,
+                    uint64_t phys_offset, int wr_fract)
+{
+       pthread_t *vcpu_threads;
+       struct kvm_vm *vm;
+       unsigned long *bmap;
+       uint64_t guest_num_pages;
+       uint64_t host_num_pages;
+       int vcpu_id;
+       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;
+#ifdef USE_CLEAR_DIRTY_LOG
+       struct kvm_enable_cap cap = {};
+       struct timespec clear_dirty_log_total = (struct timespec){0};
+#endif
+
+       vm = create_vm(mode, nr_vcpus, guest_percpu_mem_size);
+
+       perf_test_args.wr_fract = wr_fract;
+
+       guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm);
+       guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
+       host_num_pages = vm_num_host_pages(mode, guest_num_pages);
+       bmap = bitmap_alloc(host_num_pages);
+
+#ifdef USE_CLEAR_DIRTY_LOG
+       cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
+       cap.args[0] = dirty_log_manual_caps;
+       vm_enable_cap(vm, &cap);
+#endif
+
+       vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
+       TEST_ASSERT(vcpu_threads, "Memory allocation failed");
+
+       add_vcpus(vm, nr_vcpus, guest_percpu_mem_size);
+
+       sync_global_to_guest(vm, perf_test_args);
+
+       /* Start the iterations */
+       iteration = 0;
+       host_quit = false;
+
+       clock_gettime(CLOCK_MONOTONIC, &start);
+       for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
+               pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
+                              &perf_test_args.vcpu_args[vcpu_id]);
+       }
+
+       /* Allow the vCPU to populate memory */
+       pr_debug("Starting iteration %lu - Populating\n", iteration);
+       while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) != iteration)
+               pr_debug("Waiting for vcpu_last_completed_iteration == %lu\n",
+                       iteration);
+
+       ts_diff = timespec_diff_now(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);
+       vm_mem_region_set_flags(vm, TEST_MEM_SLOT_INDEX,
+                               KVM_MEM_LOG_DIRTY_PAGES);
+       ts_diff = timespec_diff_now(start);
+       pr_info("Enabling dirty logging time: %ld.%.9lds\n\n",
+               ts_diff.tv_sec, ts_diff.tv_nsec);
+
+       while (iteration < iterations) {
+               /*
+                * Incrementing the iteration number will start the vCPUs
+                * dirtying memory again.
+                */
+               clock_gettime(CLOCK_MONOTONIC, &start);
+               iteration++;
+
+               pr_debug("Starting iteration %lu\n", iteration);
+               for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
+                       while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) != iteration)
+                               pr_debug("Waiting for vCPU %d vcpu_last_completed_iteration == %lu\n",
+                                        vcpu_id, iteration);
+               }
+
+               ts_diff = timespec_diff_now(start);
+               vcpu_dirty_total = timespec_add(vcpu_dirty_total, ts_diff);
+               pr_info("Iteration %lu dirty memory time: %ld.%.9lds\n",
+                       iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
+
+               clock_gettime(CLOCK_MONOTONIC, &start);
+               kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
+
+               ts_diff = timespec_diff_now(start);
+               get_dirty_log_total = timespec_add(get_dirty_log_total,
+                                                  ts_diff);
+               pr_info("Iteration %lu get dirty log time: %ld.%.9lds\n",
+                       iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
+
+#ifdef USE_CLEAR_DIRTY_LOG
+               clock_gettime(CLOCK_MONOTONIC, &start);
+               kvm_vm_clear_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap, 0,
+                                      host_num_pages);
+
+               ts_diff = timespec_diff_now(start);
+               clear_dirty_log_total = timespec_add(clear_dirty_log_total,
+                                                    ts_diff);
+               pr_info("Iteration %lu clear dirty log time: %ld.%.9lds\n",
+                       iteration, ts_diff.tv_sec, ts_diff.tv_nsec);
+#endif
+       }
+
+       /* Tell the vcpu thread to quit */
+       host_quit = true;
+       for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)
+               pthread_join(vcpu_threads[vcpu_id], NULL);
+
+       /* Disable dirty logging */
+       clock_gettime(CLOCK_MONOTONIC, &start);
+       vm_mem_region_set_flags(vm, TEST_MEM_SLOT_INDEX, 0);
+       ts_diff = timespec_diff_now(start);
+       pr_info("Disabling dirty logging time: %ld.%.9lds\n",
+               ts_diff.tv_sec, ts_diff.tv_nsec);
+
+       avg = timespec_div(get_dirty_log_total, iterations);
+       pr_info("Get dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
+               iterations, get_dirty_log_total.tv_sec,
+               get_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
+
+#ifdef USE_CLEAR_DIRTY_LOG
+       avg = timespec_div(clear_dirty_log_total, iterations);
+       pr_info("Clear dirty log over %lu iterations took %ld.%.9lds. (Avg %ld.%.9lds/iteration)\n",
+               iterations, clear_dirty_log_total.tv_sec,
+               clear_dirty_log_total.tv_nsec, avg.tv_sec, avg.tv_nsec);
+#endif
+
+       free(bmap);
+       free(vcpu_threads);
+       ucall_uninit(vm);
+       kvm_vm_free(vm);
+}
+
+struct guest_mode {
+       bool supported;
+       bool enabled;
+};
+static struct guest_mode guest_modes[NUM_VM_MODES];
+
+#define guest_mode_init(mode, supported, enabled) ({ \
+       guest_modes[mode] = (struct guest_mode){ supported, enabled }; \
+})
+
+static void help(char *name)
+{
+       int i;
+
+       puts("");
+       printf("usage: %s [-h] [-i iterations] [-p offset] "
+              "[-m mode] [-b vcpu bytes] [-v vcpus]\n", name);
+       puts("");
+       printf(" -i: specify iteration counts (default: %"PRIu64")\n",
+              TEST_HOST_LOOP_N);
+       printf(" -p: specify guest physical test memory offset\n"
+              "     Warning: a low offset can conflict with the loaded test code.\n");
+       printf(" -m: specify the guest mode ID to test "
+              "(default: test all supported modes)\n"
+              "     This option may be used multiple times.\n"
+              "     Guest mode IDs:\n");
+       for (i = 0; i < NUM_VM_MODES; ++i) {
+               printf("         %d:    %s%s\n", i, vm_guest_mode_string(i),
+                      guest_modes[i].supported ? " (supported)" : "");
+       }
+       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(" -f: specify the fraction of pages which should be written to\n"
+              "     as opposed to simply read, in the form\n"
+              "     1/<fraction of pages to write>.\n"
+              "     (default: 1 i.e. all pages are written to.)\n");
+       printf(" -v: specify the number of vCPUs to run.\n");
+       puts("");
+       exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+       unsigned long iterations = TEST_HOST_LOOP_N;
+       bool mode_selected = false;
+       uint64_t phys_offset = 0;
+       unsigned int mode;
+       int opt, i;
+       int wr_fract = 1;
+
+#ifdef USE_CLEAR_DIRTY_LOG
+       dirty_log_manual_caps =
+               kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
+       if (!dirty_log_manual_caps) {
+               print_skip("KVM_CLEAR_DIRTY_LOG not available");
+               exit(KSFT_SKIP);
+       }
+       dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
+                                 KVM_DIRTY_LOG_INITIALLY_SET);
+#endif
+
+#ifdef __x86_64__
+       guest_mode_init(VM_MODE_PXXV48_4K, true, true);
+#endif
+#ifdef __aarch64__
+       guest_mode_init(VM_MODE_P40V48_4K, true, true);
+       guest_mode_init(VM_MODE_P40V48_64K, true, true);
+
+       {
+               unsigned int limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
+
+               if (limit >= 52)
+                       guest_mode_init(VM_MODE_P52V48_64K, true, true);
+               if (limit >= 48) {
+                       guest_mode_init(VM_MODE_P48V48_4K, true, true);
+                       guest_mode_init(VM_MODE_P48V48_64K, true, true);
+               }
+       }
+#endif
+#ifdef __s390x__
+       guest_mode_init(VM_MODE_P40V48_4K, true, true);
+#endif
+
+       while ((opt = getopt(argc, argv, "hi:p:m:b:f:v:")) != -1) {
+               switch (opt) {
+               case 'i':
+                       iterations = strtol(optarg, NULL, 10);
+                       break;
+               case 'p':
+                       phys_offset = strtoull(optarg, NULL, 0);
+                       break;
+               case 'm':
+                       if (!mode_selected) {
+                               for (i = 0; i < NUM_VM_MODES; ++i)
+                                       guest_modes[i].enabled = false;
+                               mode_selected = true;
+                       }
+                       mode = strtoul(optarg, NULL, 10);
+                       TEST_ASSERT(mode < NUM_VM_MODES,
+                                   "Guest mode ID %d too big", mode);
+                       guest_modes[mode].enabled = true;
+                       break;
+               case 'b':
+                       guest_percpu_mem_size = parse_size(optarg);
+                       break;
+               case 'f':
+                       wr_fract = atoi(optarg);
+                       TEST_ASSERT(wr_fract >= 1,
+                                   "Write fraction cannot be less than one");
+                       break;
+               case 'v':
+                       nr_vcpus = atoi(optarg);
+                       TEST_ASSERT(nr_vcpus > 0,
+                                   "Must have a positive number of vCPUs");
+                       TEST_ASSERT(nr_vcpus <= MAX_VCPUS,
+                                   "This test does not currently support\n"
+                                   "more than %d vCPUs.", MAX_VCPUS);
+                       break;
+               case 'h':
+               default:
+                       help(argv[0]);
+                       break;
+               }
+       }
+
+       TEST_ASSERT(iterations > 2, "Iterations must be greater than two");
+
+       pr_info("Test iterations: %"PRIu64"\n", iterations);
+
+       for (i = 0; i < NUM_VM_MODES; ++i) {
+               if (!guest_modes[i].enabled)
+                       continue;
+               TEST_ASSERT(guest_modes[i].supported,
+                           "Guest mode ID %d (%s) not supported.",
+                           i, vm_guest_mode_string(i));
+               run_test(i, iterations, phys_offset, wr_fract);
+       }
+
+       return 0;
+}