diff options
Diffstat (limited to 'tools/testing/selftests/kvm/lib/memstress.c')
| -rw-r--r-- | tools/testing/selftests/kvm/lib/memstress.c | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/selftests/kvm/lib/memstress.c new file mode 100644 index 000000000000..72f88e5851dd --- /dev/null +++ b/tools/testing/selftests/kvm/lib/memstress.c @@ -0,0 +1,322 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020, Google LLC. + */ +#define _GNU_SOURCE + +#include <inttypes.h> + +#include "kvm_util.h" +#include "memstress.h" +#include "processor.h" + +struct perf_test_args perf_test_args; + +/* + * 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_thread { + /* The index of the vCPU. */ + int vcpu_idx; + + /* The pthread backing the vCPU. */ + pthread_t thread; + + /* Set to true once the vCPU thread is up and running. */ + bool running; +}; + +/* The vCPU threads involved in this test. */ +static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS]; + +/* The function run by each vCPU thread, as provided by the test. */ +static void (*vcpu_thread_fn)(struct perf_test_vcpu_args *); + +/* Set to true once all vCPU threads are up and running. */ +static bool all_vcpu_threads_running; + +static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; + +/* + * Continuously write to the first 8 bytes of each page in the + * specified region. + */ +void perf_test_guest_code(uint32_t vcpu_idx) +{ + struct perf_test_args *pta = &perf_test_args; + struct perf_test_vcpu_args *vcpu_args = &pta->vcpu_args[vcpu_idx]; + struct guest_random_state rand_state; + uint64_t gva; + uint64_t pages; + uint64_t addr; + uint64_t page; + int i; + + rand_state = new_guest_random_state(pta->random_seed + vcpu_idx); + + gva = vcpu_args->gva; + pages = vcpu_args->pages; + + /* Make sure vCPU args data structure is not corrupt. */ + GUEST_ASSERT(vcpu_args->vcpu_idx == vcpu_idx); + + while (true) { + for (i = 0; i < pages; i++) { + if (pta->random_access) + page = guest_random_u32(&rand_state) % pages; + else + page = i; + + addr = gva + (page * pta->guest_page_size); + + if (guest_random_u32(&rand_state) % 100 < pta->write_percent) + *(uint64_t *)addr = 0x0123456789ABCDEF; + else + READ_ONCE(*(uint64_t *)addr); + } + + GUEST_SYNC(1); + } +} + +void perf_test_setup_vcpus(struct kvm_vm *vm, int nr_vcpus, + struct kvm_vcpu *vcpus[], + uint64_t vcpu_memory_bytes, + bool partition_vcpu_memory_access) +{ + struct perf_test_args *pta = &perf_test_args; + struct perf_test_vcpu_args *vcpu_args; + int i; + + for (i = 0; i < nr_vcpus; i++) { + vcpu_args = &pta->vcpu_args[i]; + + vcpu_args->vcpu = vcpus[i]; + vcpu_args->vcpu_idx = i; + + if (partition_vcpu_memory_access) { + vcpu_args->gva = guest_test_virt_mem + + (i * vcpu_memory_bytes); + vcpu_args->pages = vcpu_memory_bytes / + pta->guest_page_size; + vcpu_args->gpa = pta->gpa + (i * vcpu_memory_bytes); + } else { + vcpu_args->gva = guest_test_virt_mem; + vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) / + pta->guest_page_size; + vcpu_args->gpa = pta->gpa; + } + + vcpu_args_set(vcpus[i], 1, i); + + pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n", + i, vcpu_args->gpa, vcpu_args->gpa + + (vcpu_args->pages * pta->guest_page_size)); + } +} + +struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int nr_vcpus, + uint64_t vcpu_memory_bytes, int slots, + enum vm_mem_backing_src_type backing_src, + bool partition_vcpu_memory_access) +{ + struct perf_test_args *pta = &perf_test_args; + struct kvm_vm *vm; + uint64_t guest_num_pages, slot0_pages = 0; + uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src); + uint64_t region_end_gfn; + int i; + + pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); + + /* By default vCPUs will write to memory. */ + pta->write_percent = 100; + + /* + * Snapshot the non-huge page size. This is used by the guest code to + * access/dirty pages at the logging granularity. + */ + pta->guest_page_size = vm_guest_mode_params[mode].page_size; + + guest_num_pages = vm_adjust_num_guest_pages(mode, + (nr_vcpus * vcpu_memory_bytes) / pta->guest_page_size); + + TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0, + "Guest memory size is not host page size aligned."); + TEST_ASSERT(vcpu_memory_bytes % pta->guest_page_size == 0, + "Guest memory size is not guest page size aligned."); + TEST_ASSERT(guest_num_pages % slots == 0, + "Guest memory cannot be evenly divided into %d slots.", + slots); + + /* + * If using nested, allocate extra pages for the nested page tables and + * in-memory data structures. + */ + if (pta->nested) + slot0_pages += perf_test_nested_pages(nr_vcpus); + + /* + * Pass guest_num_pages to populate the page tables for test memory. + * The memory is also added to memslot 0, but that's a benign side + * effect as KVM allows aliasing HVAs in meslots. + */ + vm = __vm_create_with_vcpus(mode, nr_vcpus, slot0_pages + guest_num_pages, + perf_test_guest_code, vcpus); + + pta->vm = vm; + + /* Put the test region at the top guest physical memory. */ + region_end_gfn = vm->max_gfn + 1; + +#ifdef __x86_64__ + /* + * When running vCPUs in L2, restrict the test region to 48 bits to + * avoid needing 5-level page tables to identity map L2. + */ + if (pta->nested) + region_end_gfn = min(region_end_gfn, (1UL << 48) / pta->guest_page_size); +#endif + /* + * 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 < region_end_gfn, + "Requested more guest memory than address space allows.\n" + " guest pages: %" PRIx64 " max gfn: %" PRIx64 + " nr_vcpus: %d wss: %" PRIx64 "]\n", + guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes); + + pta->gpa = (region_end_gfn - guest_num_pages - 1) * pta->guest_page_size; + pta->gpa = align_down(pta->gpa, backing_src_pagesz); +#ifdef __s390x__ + /* Align to 1M (segment size) */ + pta->gpa = align_down(pta->gpa, 1 << 20); +#endif + pta->size = guest_num_pages * pta->guest_page_size; + pr_info("guest physical test memory: [0x%lx, 0x%lx)\n", + pta->gpa, pta->gpa + pta->size); + + /* Add extra memory slots for testing */ + for (i = 0; i < slots; i++) { + uint64_t region_pages = guest_num_pages / slots; + vm_paddr_t region_start = pta->gpa + region_pages * pta->guest_page_size * i; + + vm_userspace_mem_region_add(vm, backing_src, region_start, + PERF_TEST_MEM_SLOT_INDEX + i, + region_pages, 0); + } + + /* Do mapping for the demand paging memory slot */ + virt_map(vm, guest_test_virt_mem, pta->gpa, guest_num_pages); + + perf_test_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes, + partition_vcpu_memory_access); + + if (pta->nested) { + pr_info("Configuring vCPUs to run in L2 (nested).\n"); + perf_test_setup_nested(vm, nr_vcpus, vcpus); + } + + ucall_init(vm, NULL); + + /* Export the shared variables to the guest. */ + sync_global_to_guest(vm, perf_test_args); + + return vm; +} + +void perf_test_destroy_vm(struct kvm_vm *vm) +{ + ucall_uninit(vm); + kvm_vm_free(vm); +} + +void perf_test_set_write_percent(struct kvm_vm *vm, uint32_t write_percent) +{ + perf_test_args.write_percent = write_percent; + sync_global_to_guest(vm, perf_test_args.write_percent); +} + +void perf_test_set_random_seed(struct kvm_vm *vm, uint32_t random_seed) +{ + perf_test_args.random_seed = random_seed; + sync_global_to_guest(vm, perf_test_args.random_seed); +} + +void perf_test_set_random_access(struct kvm_vm *vm, bool random_access) +{ + perf_test_args.random_access = random_access; + sync_global_to_guest(vm, perf_test_args.random_access); +} + +uint64_t __weak perf_test_nested_pages(int nr_vcpus) +{ + return 0; +} + +void __weak perf_test_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus) +{ + pr_info("%s() not support on this architecture, skipping.\n", __func__); + exit(KSFT_SKIP); +} + +static void *vcpu_thread_main(void *data) +{ + struct vcpu_thread *vcpu = data; + int vcpu_idx = vcpu->vcpu_idx; + + if (perf_test_args.pin_vcpus) + kvm_pin_this_task_to_pcpu(perf_test_args.vcpu_to_pcpu[vcpu_idx]); + + WRITE_ONCE(vcpu->running, true); + + /* + * Wait for all vCPU threads to be up and running before calling the test- + * provided vCPU thread function. This prevents thread creation (which + * requires taking the mmap_sem in write mode) from interfering with the + * guest faulting in its memory. + */ + while (!READ_ONCE(all_vcpu_threads_running)) + ; + + vcpu_thread_fn(&perf_test_args.vcpu_args[vcpu_idx]); + + return NULL; +} + +void perf_test_start_vcpu_threads(int nr_vcpus, + void (*vcpu_fn)(struct perf_test_vcpu_args *)) +{ + int i; + + vcpu_thread_fn = vcpu_fn; + WRITE_ONCE(all_vcpu_threads_running, false); + + for (i = 0; i < nr_vcpus; i++) { + struct vcpu_thread *vcpu = &vcpu_threads[i]; + + vcpu->vcpu_idx = i; + WRITE_ONCE(vcpu->running, false); + + pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu); + } + + for (i = 0; i < nr_vcpus; i++) { + while (!READ_ONCE(vcpu_threads[i].running)) + ; + } + + WRITE_ONCE(all_vcpu_threads_running, true); +} + +void perf_test_join_vcpu_threads(int nr_vcpus) +{ + int i; + + for (i = 0; i < nr_vcpus; i++) + pthread_join(vcpu_threads[i].thread, NULL); +} |