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-rw-r--r--tools/testing/selftests/kvm/demand_paging_test.c498
1 files changed, 498 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
new file mode 100644
index 000000000..3d96a7bfa
--- /dev/null
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -0,0 +1,498 @@
+// 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
+
+#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, &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)
+{
+ 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, nr_vcpus, guest_percpu_mem_size);
+
+ perf_test_args.wr_fract = 1;
+
+ 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(nr_vcpus * sizeof(*vcpu_threads));
+ TEST_ASSERT(vcpu_threads, "Memory allocation failed");
+
+ add_vcpus(vm, nr_vcpus, guest_percpu_mem_size);
+
+ if (use_uffd) {
+ 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;
+
+ vcpu_gpa = guest_test_phys_mem + (vcpu_id * guest_percpu_mem_size);
+ PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
+ vcpu_id, vcpu_gpa, vcpu_gpa + guest_percpu_mem_size);
+
+ /* 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, guest_percpu_mem_size);
+ 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 < 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_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 < 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));
+
+ 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[])
+{
+ int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
+ bool mode_selected = false;
+ 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':
+ guest_percpu_mem_size = parse_size(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 '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);
+ }
+
+ 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 */
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