diff options
Diffstat (limited to 'tools/testing/selftests/kvm/demand_paging_test.c')
-rw-r--r-- | tools/testing/selftests/kvm/demand_paging_test.c | 661 |
1 files changed, 661 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 000000000000..360cd3ea4cd6 --- /dev/null +++ b/tools/testing/selftests/kvm/demand_paging_test.c @@ -0,0 +1,661 @@ +// 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 "test_util.h" +#include "kvm_util.h" +#include "processor.h" + +#ifdef __NR_userfaultfd + +/* The memory slot index demand page */ +#define TEST_MEM_SLOT_INDEX 1 + +/* Default guest test virtual memory offset */ +#define DEFAULT_GUEST_TEST_MEM 0xc0000000 + +#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 + +#define MAX_VCPUS 512 + +/* + * Guest/Host shared variables. Ensure addr_gva2hva() and/or + * sync_global_to/from_guest() are used when accessing from + * the host. READ/WRITE_ONCE() should also be used with anything + * that may change. + */ +static uint64_t host_page_size; +static uint64_t guest_page_size; + +static char *guest_data_prototype; + +/* + * Guest physical memory offset of the testing memory slot. + * This will be set to the topmost valid physical address minus + * the test memory size. + */ +static uint64_t guest_test_phys_mem; + +/* + * Guest virtual memory offset of the testing memory slot. + * Must not conflict with identity mapped test code. + */ +static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM; + +struct vcpu_args { + uint64_t gva; + uint64_t pages; + + /* Only used by the host userspace part of the vCPU thread */ + int vcpu_id; + struct kvm_vm *vm; +}; + +static struct vcpu_args vcpu_args[MAX_VCPUS]; + +/* + * Continuously write to the first 8 bytes of each page in the demand paging + * memory region. + */ +static void guest_code(uint32_t vcpu_id) +{ + uint64_t gva; + uint64_t pages; + int i; + + /* Make sure vCPU args data structure is not corrupt. */ + GUEST_ASSERT(vcpu_args[vcpu_id].vcpu_id == vcpu_id); + + gva = vcpu_args[vcpu_id].gva; + pages = vcpu_args[vcpu_id].pages; + + for (i = 0; i < pages; i++) { + uint64_t addr = gva + (i * guest_page_size); + + addr &= ~(host_page_size - 1); + *(uint64_t *)addr = 0x0123456789ABCDEF; + } + + GUEST_SYNC(1); +} + +static void *vcpu_worker(void *data) +{ + int ret; + struct vcpu_args *args = (struct vcpu_args *)data; + struct kvm_vm *vm = args->vm; + int vcpu_id = args->vcpu_id; + struct kvm_run *run; + struct timespec start, end, 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)); + } + + clock_gettime(CLOCK_MONOTONIC, &end); + ts_diff = timespec_sub(end, start); + PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id, + ts_diff.tv_sec, ts_diff.tv_nsec); + + return NULL; +} + +#define PAGE_SHIFT_4K 12 +#define PTES_PER_4K_PT 512 + +static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus, + uint64_t vcpu_memory_bytes) +{ + struct kvm_vm *vm; + uint64_t pages = DEFAULT_GUEST_PHY_PAGES; + + /* Account for a few pages per-vCPU for stacks */ + pages += DEFAULT_STACK_PGS * vcpus; + + /* + * Reserve twice the ammount of memory needed to map the test region and + * the page table / stacks region, at 4k, for page tables. Do the + * calculation with 4K page size: the smallest of all archs. (e.g., 64K + * page size guest will need even less memory for page tables). + */ + pages += (2 * pages) / PTES_PER_4K_PT; + pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) / + PTES_PER_4K_PT; + pages = vm_adjust_num_guest_pages(mode, pages); + + pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); + + vm = _vm_create(mode, pages, O_RDWR); + kvm_vm_elf_load(vm, program_invocation_name, 0, 0); +#ifdef __x86_64__ + vm_create_irqchip(vm); +#endif + return vm; +} + +static int handle_uffd_page_request(int uffd, uint64_t addr) +{ + pid_t tid; + struct timespec start; + struct timespec end; + struct uffdio_copy copy; + int r; + + tid = syscall(__NR_gettid); + + copy.src = (uint64_t)guest_data_prototype; + copy.dst = addr; + copy.len = 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; + } + + clock_gettime(CLOCK_MONOTONIC, &end); + + PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid, + timespec_to_ns(timespec_sub(end, start))); + PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n", + 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, end, 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++; + } + + clock_gettime(CLOCK_MONOTONIC, &end); + ts_diff = timespec_sub(end, 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, end, ts_diff; + int *pipefds = NULL; + struct kvm_vm *vm; + uint64_t guest_num_pages; + int vcpu_id; + int r; + + vm = create_vm(mode, vcpus, vcpu_memory_bytes); + + guest_page_size = vm_get_page_size(vm); + + TEST_ASSERT(vcpu_memory_bytes % guest_page_size == 0, + "Guest memory size is not guest page size aligned."); + + guest_num_pages = (vcpus * vcpu_memory_bytes) / guest_page_size; + guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages); + + /* + * If there should be more memory in the guest test region than there + * can be pages in the guest, it will definitely cause problems. + */ + TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm), + "Requested more guest memory than address space allows.\n" + " guest pages: %lx max gfn: %x vcpus: %d wss: %lx]\n", + guest_num_pages, vm_get_max_gfn(vm), vcpus, + vcpu_memory_bytes); + + host_page_size = getpagesize(); + TEST_ASSERT(vcpu_memory_bytes % host_page_size == 0, + "Guest memory size is not host page size aligned."); + + guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) * + guest_page_size; + guest_test_phys_mem &= ~(host_page_size - 1); + +#ifdef __s390x__ + /* Align to 1M (segment size) */ + guest_test_phys_mem &= ~((1 << 20) - 1); +#endif + + pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem); + + /* Add an extra memory slot for testing demand paging */ + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, + guest_test_phys_mem, + TEST_MEM_SLOT_INDEX, + guest_num_pages, 0); + + /* Do mapping for the demand paging memory slot */ + virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages, 0); + + ucall_init(vm, NULL); + + guest_data_prototype = malloc(host_page_size); + TEST_ASSERT(guest_data_prototype, + "Failed to allocate buffer for guest data pattern"); + memset(guest_data_prototype, 0xAB, host_page_size); + + vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads)); + TEST_ASSERT(vcpu_threads, "Memory allocation failed"); + + 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; + + vm_vcpu_add_default(vm, vcpu_id, guest_code); + + 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); + + if (use_uffd) { + /* + * 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); + } + +#ifdef __x86_64__ + vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid()); +#endif + + vcpu_args[vcpu_id].vm = vm; + vcpu_args[vcpu_id].vcpu_id = vcpu_id; + vcpu_args[vcpu_id].gva = guest_test_virt_mem + + (vcpu_id * vcpu_memory_bytes); + vcpu_args[vcpu_id].pages = vcpu_memory_bytes / guest_page_size; + } + + /* Export the shared variables to the guest */ + sync_global_to_guest(vm, host_page_size); + sync_global_to_guest(vm, guest_page_size); + sync_global_to_guest(vm, vcpu_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, + &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); + } + + pr_info("All vCPU threads joined\n"); + + clock_gettime(CLOCK_MONOTONIC, &end); + + 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); + } + } + + ts_diff = timespec_sub(end, start); + 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", + guest_num_pages / ((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 */ |