diff options
Diffstat (limited to 'tools/testing/selftests/kvm/demand_paging_test.c')
-rw-r--r-- | tools/testing/selftests/kvm/demand_paging_test.c | 308 |
1 files changed, 308 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 0000000000..09c116a82a --- /dev/null +++ b/tools/testing/selftests/kvm/demand_paging_test.c @@ -0,0 +1,308 @@ +// 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 "memstress.h" +#include "guest_modes.h" +#include "userfaultfd_util.h" + +#ifdef __NR_userfaultfd + +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(struct memstress_vcpu_args *vcpu_args) +{ + struct kvm_vcpu *vcpu = vcpu_args->vcpu; + int vcpu_idx = vcpu_args->vcpu_idx; + struct kvm_run *run = vcpu->run; + struct timespec start; + struct timespec ts_diff; + int ret; + + clock_gettime(CLOCK_MONOTONIC, &start); + + /* Let the guest access its memory */ + ret = _vcpu_run(vcpu); + TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret); + if (get_ucall(vcpu, 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_idx, + ts_diff.tv_sec, ts_diff.tv_nsec); +} + +static int handle_uffd_page_request(int uffd_mode, int uffd, + struct uffd_msg *msg) +{ + pid_t tid = syscall(__NR_gettid); + uint64_t addr = msg->arg.pagefault.address; + 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, ©); + 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; +} + +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 prefault_mem(void *alias, uint64_t len) +{ + size_t p; + + 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); + } +} + +static void run_test(enum vm_guest_mode mode, void *arg) +{ + struct memstress_vcpu_args *vcpu_args; + struct test_params *p = arg; + struct uffd_desc **uffd_descs = NULL; + struct timespec start; + struct timespec ts_diff; + struct kvm_vm *vm; + int i; + + vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1, + p->src_type, p->partition_vcpu_memory_access); + + 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); + + if (p->uffd_mode == UFFDIO_REGISTER_MODE_MINOR) { + for (i = 0; i < nr_vcpus; i++) { + vcpu_args = &memstress_args.vcpu_args[i]; + prefault_mem(addr_gpa2alias(vm, vcpu_args->gpa), + vcpu_args->pages * memstress_args.guest_page_size); + } + } + + if (p->uffd_mode) { + uffd_descs = malloc(nr_vcpus * sizeof(struct uffd_desc *)); + TEST_ASSERT(uffd_descs, "Memory allocation failed"); + for (i = 0; i < nr_vcpus; i++) { + void *vcpu_hva; + + vcpu_args = &memstress_args.vcpu_args[i]; + + /* Cache the host addresses of the region */ + vcpu_hva = addr_gpa2hva(vm, vcpu_args->gpa); + /* + * Set up user fault fd to handle demand paging + * requests. + */ + uffd_descs[i] = uffd_setup_demand_paging( + p->uffd_mode, p->uffd_delay, vcpu_hva, + vcpu_args->pages * memstress_args.guest_page_size, + &handle_uffd_page_request); + } + } + + pr_info("Finished creating vCPUs and starting uffd threads\n"); + + clock_gettime(CLOCK_MONOTONIC, &start); + memstress_start_vcpu_threads(nr_vcpus, vcpu_worker); + pr_info("Started all vCPUs\n"); + + memstress_join_vcpu_threads(nr_vcpus); + ts_diff = timespec_elapsed(start); + pr_info("All vCPU threads joined\n"); + + if (p->uffd_mode) { + /* Tell the user fault fd handler threads to quit */ + for (i = 0; i < nr_vcpus; i++) + uffd_stop_demand_paging(uffd_descs[i]); + } + + 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", + memstress_args.vcpu_args[0].pages * nr_vcpus / + ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / NSEC_PER_SEC)); + + memstress_destroy_vm(vm); + + free(guest_data_prototype); + if (p->uffd_mode) + free(uffd_descs); +} + +static void help(char *name) +{ + puts(""); + printf("usage: %s [-h] [-m vm_mode] [-u uffd_mode] [-d uffd_delay_usec]\n" + " [-b memory] [-s type] [-v vcpus] [-c cpu_list] [-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"); + kvm_print_vcpu_pinning_help(); + 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"); + backing_src_help("-s"); + 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); + const char *cpulist = NULL; + struct test_params p = { + .src_type = DEFAULT_VM_MEM_SRC, + .partition_vcpu_memory_access = true, + }; + int opt; + + guest_modes_append_default(); + + while ((opt = getopt(argc, argv, "hm:u:d:b:s:v:c: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 's': + p.src_type = 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 'c': + cpulist = optarg; + 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 -s"); + } + + if (cpulist) { + kvm_parse_vcpu_pinning(cpulist, memstress_args.vcpu_to_pcpu, + nr_vcpus); + memstress_args.pin_vcpus = true; + } + + 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 */ |