blob: 10edae425ab3c140336cc227c3258f5076f348cb [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* KVM demand paging test
* Adapted from dirty_log_test.c
*
* Copyright (C) 2018, Red Hat, Inc.
* Copyright (C) 2019, Google, Inc.
*/
#define _GNU_SOURCE /* for pipe2 */
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <poll.h>
#include <pthread.h>
#include <linux/userfaultfd.h>
#include <sys/syscall.h>
#include "kvm_util.h"
#include "test_util.h"
#include "perf_test_util.h"
#include "guest_modes.h"
#ifdef __NR_userfaultfd
#ifdef PRINT_PER_PAGE_UPDATES
#define PER_PAGE_DEBUG(...) printf(__VA_ARGS__)
#else
#define PER_PAGE_DEBUG(...) _no_printf(__VA_ARGS__)
#endif
#ifdef PRINT_PER_VCPU_UPDATES
#define PER_VCPU_DEBUG(...) printf(__VA_ARGS__)
#else
#define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)
#endif
static int nr_vcpus = 1;
static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
static size_t demand_paging_size;
static char *guest_data_prototype;
static void *vcpu_worker(void *data)
{
int ret;
struct perf_test_vcpu_args *vcpu_args = (struct perf_test_vcpu_args *)data;
int vcpu_id = vcpu_args->vcpu_id;
struct kvm_vm *vm = perf_test_args.vm;
struct kvm_run *run;
struct timespec start;
struct timespec ts_diff;
run = vcpu_state(vm, vcpu_id);
clock_gettime(CLOCK_MONOTONIC, &start);
/* Let the guest access its memory */
ret = _vcpu_run(vm, vcpu_id);
TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
if (get_ucall(vm, vcpu_id, NULL) != UCALL_SYNC) {
TEST_ASSERT(false,
"Invalid guest sync status: exit_reason=%s\n",
exit_reason_str(run->exit_reason));
}
ts_diff = timespec_elapsed(start);
PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id,
ts_diff.tv_sec, ts_diff.tv_nsec);
return NULL;
}
static int handle_uffd_page_request(int uffd_mode, int uffd, uint64_t addr)
{
pid_t tid = syscall(__NR_gettid);
struct timespec start;
struct timespec ts_diff;
int r;
clock_gettime(CLOCK_MONOTONIC, &start);
if (uffd_mode == UFFDIO_REGISTER_MODE_MISSING) {
struct uffdio_copy copy;
copy.src = (uint64_t)guest_data_prototype;
copy.dst = addr;
copy.len = demand_paging_size;
copy.mode = 0;
r = ioctl(uffd, UFFDIO_COPY, &copy);
if (r == -1) {
pr_info("Failed UFFDIO_COPY in 0x%lx from thread %d with errno: %d\n",
addr, tid, errno);
return r;
}
} else if (uffd_mode == UFFDIO_REGISTER_MODE_MINOR) {
struct uffdio_continue cont = {0};
cont.range.start = addr;
cont.range.len = demand_paging_size;
r = ioctl(uffd, UFFDIO_CONTINUE, &cont);
if (r == -1) {
pr_info("Failed UFFDIO_CONTINUE in 0x%lx from thread %d with errno: %d\n",
addr, tid, errno);
return r;
}
} else {
TEST_FAIL("Invalid uffd mode %d", uffd_mode);
}
ts_diff = timespec_elapsed(start);
PER_PAGE_DEBUG("UFFD page-in %d \t%ld ns\n", tid,
timespec_to_ns(ts_diff));
PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
demand_paging_size, addr, tid);
return 0;
}
bool quit_uffd_thread;
struct uffd_handler_args {
int uffd_mode;
int uffd;
int pipefd;
useconds_t delay;
};
static void *uffd_handler_thread_fn(void *arg)
{
struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg;
int uffd = uffd_args->uffd;
int pipefd = uffd_args->pipefd;
useconds_t delay = uffd_args->delay;
int64_t pages = 0;
struct timespec start;
struct timespec ts_diff;
clock_gettime(CLOCK_MONOTONIC, &start);
while (!quit_uffd_thread) {
struct uffd_msg msg;
struct pollfd pollfd[2];
char tmp_chr;
int r;
uint64_t addr;
pollfd[0].fd = uffd;
pollfd[0].events = POLLIN;
pollfd[1].fd = pipefd;
pollfd[1].events = POLLIN;
r = poll(pollfd, 2, -1);
switch (r) {
case -1:
pr_info("poll err");
continue;
case 0:
continue;
case 1:
break;
default:
pr_info("Polling uffd returned %d", r);
return NULL;
}
if (pollfd[0].revents & POLLERR) {
pr_info("uffd revents has POLLERR");
return NULL;
}
if (pollfd[1].revents & POLLIN) {
r = read(pollfd[1].fd, &tmp_chr, 1);
TEST_ASSERT(r == 1,
"Error reading pipefd in UFFD thread\n");
return NULL;
}
if (!(pollfd[0].revents & POLLIN))
continue;
r = read(uffd, &msg, sizeof(msg));
if (r == -1) {
if (errno == EAGAIN)
continue;
pr_info("Read of uffd got errno %d\n", errno);
return NULL;
}
if (r != sizeof(msg)) {
pr_info("Read on uffd returned unexpected size: %d bytes", r);
return NULL;
}
if (!(msg.event & UFFD_EVENT_PAGEFAULT))
continue;
if (delay)
usleep(delay);
addr = msg.arg.pagefault.address;
r = handle_uffd_page_request(uffd_args->uffd_mode, uffd, addr);
if (r < 0)
return NULL;
pages++;
}
ts_diff = timespec_elapsed(start);
PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
pages, ts_diff.tv_sec, ts_diff.tv_nsec,
pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
return NULL;
}
static void setup_demand_paging(struct kvm_vm *vm,
pthread_t *uffd_handler_thread, int pipefd,
int uffd_mode, useconds_t uffd_delay,
struct uffd_handler_args *uffd_args,
void *hva, void *alias, uint64_t len)
{
bool is_minor = (uffd_mode == UFFDIO_REGISTER_MODE_MINOR);
int uffd;
struct uffdio_api uffdio_api;
struct uffdio_register uffdio_register;
uint64_t expected_ioctls = ((uint64_t) 1) << _UFFDIO_COPY;
PER_PAGE_DEBUG("Userfaultfd %s mode, faults resolved with %s\n",
is_minor ? "MINOR" : "MISSING",
is_minor ? "UFFDIO_CONINUE" : "UFFDIO_COPY");
/* In order to get minor faults, prefault via the alias. */
if (is_minor) {
size_t p;
expected_ioctls = ((uint64_t) 1) << _UFFDIO_CONTINUE;
TEST_ASSERT(alias != NULL, "Alias required for minor faults");
for (p = 0; p < (len / demand_paging_size); ++p) {
memcpy(alias + (p * demand_paging_size),
guest_data_prototype, demand_paging_size);
}
}
uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
TEST_ASSERT(uffd >= 0, "uffd creation failed, errno: %d", errno);
uffdio_api.api = UFFD_API;
uffdio_api.features = 0;
TEST_ASSERT(ioctl(uffd, UFFDIO_API, &uffdio_api) != -1,
"ioctl UFFDIO_API failed: %" PRIu64,
(uint64_t)uffdio_api.api);
uffdio_register.range.start = (uint64_t)hva;
uffdio_register.range.len = len;
uffdio_register.mode = uffd_mode;
TEST_ASSERT(ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) != -1,
"ioctl UFFDIO_REGISTER failed");
TEST_ASSERT((uffdio_register.ioctls & expected_ioctls) ==
expected_ioctls, "missing userfaultfd ioctls");
uffd_args->uffd_mode = uffd_mode;
uffd_args->uffd = uffd;
uffd_args->pipefd = pipefd;
uffd_args->delay = uffd_delay;
pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
uffd_args);
PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
hva, hva + len);
}
struct test_params {
int uffd_mode;
useconds_t uffd_delay;
enum vm_mem_backing_src_type src_type;
bool partition_vcpu_memory_access;
};
static void run_test(enum vm_guest_mode mode, void *arg)
{
struct test_params *p = arg;
pthread_t *vcpu_threads;
pthread_t *uffd_handler_threads = NULL;
struct uffd_handler_args *uffd_args = NULL;
struct timespec start;
struct timespec ts_diff;
int *pipefds = NULL;
struct kvm_vm *vm;
int vcpu_id;
int r;
vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1,
p->src_type);
perf_test_args.wr_fract = 1;
demand_paging_size = get_backing_src_pagesz(p->src_type);
guest_data_prototype = malloc(demand_paging_size);
TEST_ASSERT(guest_data_prototype,
"Failed to allocate buffer for guest data pattern");
memset(guest_data_prototype, 0xAB, demand_paging_size);
vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
TEST_ASSERT(vcpu_threads, "Memory allocation failed");
perf_test_setup_vcpus(vm, nr_vcpus, guest_percpu_mem_size,
p->partition_vcpu_memory_access);
if (p->uffd_mode) {
uffd_handler_threads =
malloc(nr_vcpus * sizeof(*uffd_handler_threads));
TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
uffd_args = malloc(nr_vcpus * sizeof(*uffd_args));
TEST_ASSERT(uffd_args, "Memory allocation failed");
pipefds = malloc(sizeof(int) * nr_vcpus * 2);
TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
vm_paddr_t vcpu_gpa;
void *vcpu_hva;
void *vcpu_alias;
uint64_t vcpu_mem_size;
if (p->partition_vcpu_memory_access) {
vcpu_gpa = guest_test_phys_mem +
(vcpu_id * guest_percpu_mem_size);
vcpu_mem_size = guest_percpu_mem_size;
} else {
vcpu_gpa = guest_test_phys_mem;
vcpu_mem_size = guest_percpu_mem_size * nr_vcpus;
}
PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_mem_size);
/* Cache the host addresses of the region */
vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);
vcpu_alias = addr_gpa2alias(vm, vcpu_gpa);
/*
* Set up user fault fd to handle demand paging
* requests.
*/
r = pipe2(&pipefds[vcpu_id * 2],
O_CLOEXEC | O_NONBLOCK);
TEST_ASSERT(!r, "Failed to set up pipefd");
setup_demand_paging(vm, &uffd_handler_threads[vcpu_id],
pipefds[vcpu_id * 2], p->uffd_mode,
p->uffd_delay, &uffd_args[vcpu_id],
vcpu_hva, vcpu_alias,
vcpu_mem_size);
}
}
/* Export the shared variables to the guest */
sync_global_to_guest(vm, perf_test_args);
pr_info("Finished creating vCPUs and starting uffd threads\n");
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]);
}
pr_info("Started all vCPUs\n");
/* Wait for the vcpu threads to quit */
for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
pthread_join(vcpu_threads[vcpu_id], NULL);
PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
}
ts_diff = timespec_elapsed(start);
pr_info("All vCPU threads joined\n");
if (p->uffd_mode) {
char c;
/* Tell the user fault fd handler threads to quit */
for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
r = write(pipefds[vcpu_id * 2 + 1], &c, 1);
TEST_ASSERT(r == 1, "Unable to write to pipefd");
pthread_join(uffd_handler_threads[vcpu_id], NULL);
}
}
pr_info("Total guest execution time: %ld.%.9lds\n",
ts_diff.tv_sec, ts_diff.tv_nsec);
pr_info("Overall demand paging rate: %f pgs/sec\n",
perf_test_args.vcpu_args[0].pages * nr_vcpus /
((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
perf_test_destroy_vm(vm);
free(guest_data_prototype);
free(vcpu_threads);
if (p->uffd_mode) {
free(uffd_handler_threads);
free(uffd_args);
free(pipefds);
}
}
static void help(char *name)
{
puts("");
printf("usage: %s [-h] [-m vm_mode] [-u uffd_mode] [-d uffd_delay_usec]\n"
" [-b memory] [-t type] [-v vcpus] [-o]\n", name);
guest_modes_help();
printf(" -u: use userfaultfd to handle vCPU page faults. Mode is a\n"
" UFFD registration mode: 'MISSING' or 'MINOR'.\n");
printf(" -d: add a delay in usec to the User Fault\n"
" FD handler to simulate demand paging\n"
" overheads. Ignored without -u.\n");
printf(" -b: specify the size of the memory region which should be\n"
" demand paged by each vCPU. e.g. 10M or 3G.\n"
" Default: 1G\n");
printf(" -t: The type of backing memory to use. Default: anonymous\n");
backing_src_help();
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");
puts("");
exit(0);
}
int main(int argc, char *argv[])
{
int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
struct test_params p = {
.src_type = VM_MEM_SRC_ANONYMOUS,
.partition_vcpu_memory_access = true,
};
int opt;
guest_modes_append_default();
while ((opt = getopt(argc, argv, "hm:u:d:b:t:v:o")) != -1) {
switch (opt) {
case 'm':
guest_modes_cmdline(optarg);
break;
case 'u':
if (!strcmp("MISSING", optarg))
p.uffd_mode = UFFDIO_REGISTER_MODE_MISSING;
else if (!strcmp("MINOR", optarg))
p.uffd_mode = UFFDIO_REGISTER_MODE_MINOR;
TEST_ASSERT(p.uffd_mode, "UFFD mode must be 'MISSING' or 'MINOR'.");
break;
case 'd':
p.uffd_delay = strtoul(optarg, NULL, 0);
TEST_ASSERT(p.uffd_delay >= 0, "A negative UFFD delay is not supported.");
break;
case 'b':
guest_percpu_mem_size = parse_size(optarg);
break;
case 't':
p.src_type = parse_backing_src_type(optarg);
break;
case 'v':
nr_vcpus = atoi(optarg);
TEST_ASSERT(nr_vcpus > 0 && nr_vcpus <= max_vcpus,
"Invalid number of vcpus, must be between 1 and %d", max_vcpus);
break;
case 'o':
p.partition_vcpu_memory_access = false;
break;
case 'h':
default:
help(argv[0]);
break;
}
}
if (p.uffd_mode == UFFDIO_REGISTER_MODE_MINOR &&
!backing_src_is_shared(p.src_type)) {
TEST_FAIL("userfaultfd MINOR mode requires shared memory; pick a different -t");
}
for_each_guest_mode(run_test, &p);
return 0;
}
#else /* __NR_userfaultfd */
#warning "missing __NR_userfaultfd definition"
int main(void)
{
print_skip("__NR_userfaultfd must be present for userfaultfd test");
return KSFT_SKIP;
}
#endif /* __NR_userfaultfd */