tools/testing/selftests/kvm/dirty_log_perf_test.c - linux/kernel/git/dhowells/linux-fs - Git at Google

 // 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"

 #ifdef __aarch64__
 #include "aarch64/vgic.h"

 #define GICD_BASE_GPA			0x8000000ULL
 #define GICR_BASE_GPA			0x80A0000ULL

 static int gic_fd;

 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
 {
 	/*
 	 * The test can still run even if hardware does not support GICv3, as it
 	 * is only an optimization to reduce guest exits.
 	 */
 	gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
 }

 static void arch_cleanup_vm(struct kvm_vm *vm)
 {
 	if (gic_fd > 0)
 		close(gic_fd);
 }

 #else /* __aarch64__ */

 static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
 {
 }

 static void arch_cleanup_vm(struct kvm_vm *vm)
 {
 }

 #endif

 /* 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 uint64_t 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;
 	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;
 	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\n", ret);
 		TEST_ASSERT(get_ucall(vcpu, 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_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;
 	uint64_t phys_offset;
 	bool partition_vcpu_memory_access;
 	enum vm_mem_backing_src_type backing_src;
 	int slots;
 	uint32_t write_percent;
 	uint32_t random_seed;
 	bool random_access;
 };

 static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
 {
 	int i;

 	for (i = 0; i < slots; i++) {
 		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
 		int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;

 		vm_mem_region_set_flags(vm, slot, flags);
 	}
 }

 static inline void enable_dirty_logging(struct kvm_vm *vm, int slots)
 {
 	toggle_dirty_logging(vm, slots, true);
 }

 static inline void disable_dirty_logging(struct kvm_vm *vm, int slots)
 {
 	toggle_dirty_logging(vm, slots, false);
 }

 static void get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots)
 {
 	int i;

 	for (i = 0; i < slots; i++) {
 		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;

 		kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);
 	}
 }

 static void clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
 			    int slots, uint64_t pages_per_slot)
 {
 	int i;

 	for (i = 0; i < slots; i++) {
 		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;

 		kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
 	}
 }

 static unsigned long **alloc_bitmaps(int slots, uint64_t pages_per_slot)
 {
 	unsigned long **bitmaps;
 	int i;

 	bitmaps = malloc(slots * sizeof(bitmaps[0]));
 	TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");

 	for (i = 0; i < slots; i++) {
 		bitmaps[i] = bitmap_zalloc(pages_per_slot);
 		TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");
 	}

 	return bitmaps;
 }

 static void free_bitmaps(unsigned long *bitmaps[], int slots)
 {
 	int i;

 	for (i = 0; i < slots; i++)
 		free(bitmaps[i]);

 	free(bitmaps);
 }

 static void run_test(enum vm_guest_mode mode, void *arg)
 {
 	struct test_params *p = arg;
 	struct kvm_vm *vm;
 	unsigned long **bitmaps;
 	uint64_t guest_num_pages;
 	uint64_t host_num_pages;
 	uint64_t 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);

 	pr_info("Random seed: %u\n", p->random_seed);
 	memstress_set_random_seed(vm, p->random_seed);
 	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 = 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);

 	arch_setup_vm(vm, nr_vcpus);

 	/* 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);
 	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);
 		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);
 			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);
 	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);
 	}

 	free_bitmaps(bitmaps, p->slots);
 	arch_cleanup_vm(vm);
 	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");
 	printf(" -c: Pin tasks to physical CPUs.  Takes a list of comma separated\n"
 	       "     values (target pCPU), one for each vCPU, plus an optional\n"
 	       "     entry for the main application task (specified via entry\n"
 	       "     <nr_vcpus + 1>).  If used, entries must be provided for all\n"
 	       "     vCPUs, i.e. pinning vCPUs is all or nothing.\n\n"
 	       "     E.g. to create 3 vCPUs, pin vCPU0=>pCPU22, vCPU1=>pCPU23,\n"
 	       "     vCPU2=>pCPU24, and pin the application task to pCPU50:\n\n"
 	       "         ./dirty_log_perf_test -v 3 -c 22,23,24,50\n\n"
 	       "     To leave the application task unpinned, drop the final entry:\n\n"
 	       "         ./dirty_log_perf_test -v 3 -c 22,23,24\n\n"
 	       "     (default: no pinning)\n");
 	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,
 		.random_seed = 1,
 		.write_percent = 100,
 	};
 	int opt;

 	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':
 			p.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;
 }
	// 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"

	#ifdef __aarch64__
	#include "aarch64/vgic.h"

	#define GICD_BASE_GPA 0x8000000ULL
	#define GICR_BASE_GPA 0x80A0000ULL

	static int gic_fd;

	static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
	{
	/*
	* The test can still run even if hardware does not support GICv3, as it
	* is only an optimization to reduce guest exits.
	*/
	gic_fd = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
	}

	static void arch_cleanup_vm(struct kvm_vm *vm)
	{
	if (gic_fd > 0)
	close(gic_fd);
	}

	#else /* __aarch64__ */

	static void arch_setup_vm(struct kvm_vm *vm, unsigned int nr_vcpus)
	{
	}

	static void arch_cleanup_vm(struct kvm_vm *vm)
	{
	}

	#endif

	/* 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 uint64_t 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;
	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;
	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\n", ret);
	TEST_ASSERT(get_ucall(vcpu, 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_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;
	uint64_t phys_offset;
	bool partition_vcpu_memory_access;
	enum vm_mem_backing_src_type backing_src;
	int slots;
	uint32_t write_percent;
	uint32_t random_seed;
	bool random_access;
	};

	static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
	{
	int i;

	for (i = 0; i < slots; i++) {
	int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
	int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;

	vm_mem_region_set_flags(vm, slot, flags);
	}
	}

	static inline void enable_dirty_logging(struct kvm_vm *vm, int slots)
	{
	toggle_dirty_logging(vm, slots, true);
	}

	static inline void disable_dirty_logging(struct kvm_vm *vm, int slots)
	{
	toggle_dirty_logging(vm, slots, false);
	}

	static void get_dirty_log(struct kvm_vm vm, unsigned long bitmaps[], int slots)
	{
	int i;

	for (i = 0; i < slots; i++) {
	int slot = MEMSTRESS_MEM_SLOT_INDEX + i;

	kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);
	}
	}

	static void clear_dirty_log(struct kvm_vm vm, unsigned long bitmaps[],
	int slots, uint64_t pages_per_slot)
	{
	int i;

	for (i = 0; i < slots; i++) {
	int slot = MEMSTRESS_MEM_SLOT_INDEX + i;

	kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
	}
	}

	static unsigned long **alloc_bitmaps(int slots, uint64_t pages_per_slot)
	{
	unsigned long **bitmaps;
	int i;

	bitmaps = malloc(slots * sizeof(bitmaps[0]));
	TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");

	for (i = 0; i < slots; i++) {
	bitmaps[i] = bitmap_zalloc(pages_per_slot);
	TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");
	}

	return bitmaps;
	}

	static void free_bitmaps(unsigned long *bitmaps[], int slots)
	{
	int i;

	for (i = 0; i < slots; i++)
	free(bitmaps[i]);

	free(bitmaps);
	}

	static void run_test(enum vm_guest_mode mode, void *arg)
	{
	struct test_params *p = arg;
	struct kvm_vm *vm;
	unsigned long **bitmaps;
	uint64_t guest_num_pages;
	uint64_t host_num_pages;
	uint64_t 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);

	pr_info("Random seed: %u\n", p->random_seed);
	memstress_set_random_seed(vm, p->random_seed);
	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 = 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);

	arch_setup_vm(vm, nr_vcpus);

	/* 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);
	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);
	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);
	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);
	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);
	}

	free_bitmaps(bitmaps, p->slots);
	arch_cleanup_vm(vm);
	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");
	printf(" -c: Pin tasks to physical CPUs. Takes a list of comma separated\n"
	" values (target pCPU), one for each vCPU, plus an optional\n"
	" entry for the main application task (specified via entry\n"
	" <nr_vcpus + 1>). If used, entries must be provided for all\n"
	" vCPUs, i.e. pinning vCPUs is all or nothing.\n\n"
	" E.g. to create 3 vCPUs, pin vCPU0=>pCPU22, vCPU1=>pCPU23,\n"
	" vCPU2=>pCPU24, and pin the application task to pCPU50:\n\n"
	" ./dirty_log_perf_test -v 3 -c 22,23,24,50\n\n"
	" To leave the application task unpinned, drop the final entry:\n\n"
	" ./dirty_log_perf_test -v 3 -c 22,23,24\n\n"
	" (default: no pinning)\n");
	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,
	.random_seed = 1,
	.write_percent = 100,
	};
	int opt;

	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':
	p.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;
	}