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demand_paging_test.c
demand_paging_test.c 12.29 KiB
// 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 program_invocation_name */
#include <stdio.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <time.h>
#include <poll.h>
#include <pthread.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/userfaultfd.h>
#include "perf_test_util.h"
#include "processor.h"
#include "test_util.h"
#ifdef __NR_userfaultfd
#define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */
#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 char *guest_data_prototype;
static void *vcpu_worker(void *data)
{
int ret;
struct vcpu_args *vcpu_args = (struct 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;
vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
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_diff_now(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, uint64_t addr)
{
pid_t tid;
struct timespec start;
struct timespec ts_diff;
struct uffdio_copy copy;
int r;
tid = syscall(__NR_gettid);
copy.src = (uint64_t)guest_data_prototype;
copy.dst = addr;
copy.len = perf_test_args.host_page_size;
copy.mode = 0;
clock_gettime(CLOCK_MONOTONIC, &start);
r = ioctl(uffd, UFFDIO_COPY, ©);
if (r == -1) {
pr_info("Failed Paged in 0x%lx from thread %d with errno: %d\n",
addr, tid, errno);
return r;
}
ts_diff = timespec_diff_now(start);
PER_PAGE_DEBUG("UFFDIO_COPY %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",
perf_test_args.host_page_size, addr, tid);
return 0;
}
bool quit_uffd_thread;
struct uffd_handler_args {
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 gor errno %d", 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, addr);
if (r < 0)
return NULL;
pages++;
}
ts_diff = timespec_diff_now(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 int setup_demand_paging(struct kvm_vm *vm,
pthread_t *uffd_handler_thread, int pipefd,
useconds_t uffd_delay,
struct uffd_handler_args *uffd_args,
void *hva, uint64_t len)
{
int uffd; struct uffdio_api uffdio_api;
struct uffdio_register uffdio_register;
uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
if (uffd == -1) {
pr_info("uffd creation failed\n");
return -1;
}
uffdio_api.api = UFFD_API;
uffdio_api.features = 0;
if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
pr_info("ioctl uffdio_api failed\n");
return -1;
}
uffdio_register.range.start = (uint64_t)hva;
uffdio_register.range.len = len;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
pr_info("ioctl uffdio_register failed\n");
return -1;
}
if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
UFFD_API_RANGE_IOCTLS) {
pr_info("unexpected userfaultfd ioctl set\n");
return -1;
}
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);
return 0;
}
static void run_test(enum vm_guest_mode mode, bool use_uffd,
useconds_t uffd_delay, int vcpus,
uint64_t vcpu_memory_bytes)
{
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 = create_vm(mode, vcpus, vcpu_memory_bytes);
guest_data_prototype = malloc(perf_test_args.host_page_size);
TEST_ASSERT(guest_data_prototype,
"Failed to allocate buffer for guest data pattern");
memset(guest_data_prototype, 0xAB, perf_test_args.host_page_size);
vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));
TEST_ASSERT(vcpu_threads, "Memory allocation failed");
add_vcpus(vm, vcpus, vcpu_memory_bytes);
if (use_uffd) {
uffd_handler_threads = malloc(vcpus * sizeof(*uffd_handler_threads));
TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
uffd_args = malloc(vcpus * sizeof(*uffd_args));
TEST_ASSERT(uffd_args, "Memory allocation failed");
pipefds = malloc(sizeof(int) * vcpus * 2);
TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
vm_paddr_t vcpu_gpa;
void *vcpu_hva;
vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);
PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);
/* Cache the HVA pointer of the region */
vcpu_hva = addr_gpa2hva(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");
r = setup_demand_paging(vm,
&uffd_handler_threads[vcpu_id],
pipefds[vcpu_id * 2],
uffd_delay, &uffd_args[vcpu_id],
vcpu_hva, vcpu_memory_bytes);
if (r < 0)
exit(-r);
}
}
/* 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 < 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 < vcpus; vcpu_id++) {
pthread_join(vcpu_threads[vcpu_id], NULL);
PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
}
ts_diff = timespec_diff_now(start);
pr_info("All vCPU threads joined\n");
if (use_uffd) {
char c;
/* Tell the user fault fd handler threads to quit */
for (vcpu_id = 0; vcpu_id < 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 * vcpus /
((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
ucall_uninit(vm);
kvm_vm_free(vm);
free(guest_data_prototype);
free(vcpu_threads);
if (use_uffd) {
free(uffd_handler_threads);
free(uffd_args);
free(pipefds);
}
}
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] [-m mode] [-u] [-d uffd_delay_usec]\n"
" [-b memory] [-v vcpus]\n", name);
printf(" -m: specify the guest mode ID to test\n"
" (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(" -u: use User Fault FD to handle vCPU page\n"
" faults.\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(" -v: specify the number of vCPUs to run.\n");
puts("");
exit(0);
}
int main(int argc, char *argv[])
{
bool mode_selected = false;
uint64_t vcpu_memory_bytes = DEFAULT_GUEST_TEST_MEM_SIZE;
int vcpus = 1;
unsigned int mode;
int opt, i;
bool use_uffd = false;
useconds_t uffd_delay = 0;
#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, "hm:ud:b:v:")) != -1) {
switch (opt) {
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 'u':
use_uffd = true;
break;
case 'd':
uffd_delay = strtoul(optarg, NULL, 0);
TEST_ASSERT(uffd_delay >= 0,
"A negative UFFD delay is not supported.");
break;
case 'b':
vcpu_memory_bytes = parse_size(optarg);
break;
case 'v':
vcpus = atoi(optarg);
TEST_ASSERT(vcpus > 0,
"Must have a positive number of vCPUs");
TEST_ASSERT(vcpus <= MAX_VCPUS,
"This test does not currently support\n"
"more than %d vCPUs.", MAX_VCPUS);
break;
case 'h':
default:
help(argv[0]);
break;
}
}
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, use_uffd, uffd_delay, vcpus, vcpu_memory_bytes);
}
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 */