diff options
Diffstat (limited to 'tools/testing/selftests/kvm/dirty_log_test.c')
| -rw-r--r-- | tools/testing/selftests/kvm/dirty_log_test.c | 909 |
1 files changed, 909 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c new file mode 100644 index 000000000000..d58a641b0e6a --- /dev/null +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -0,0 +1,909 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KVM dirty page logging test + * + * Copyright (C) 2018, Red Hat, Inc. + */ +#include <stdio.h> +#include <stdlib.h> +#include <pthread.h> +#include <semaphore.h> +#include <sys/types.h> +#include <signal.h> +#include <errno.h> +#include <linux/bitmap.h> +#include <linux/bitops.h> +#include <linux/atomic.h> +#include <asm/barrier.h> + +#include "kvm_util.h" +#include "test_util.h" +#include "guest_modes.h" +#include "processor.h" +#include "ucall_common.h" + +#define DIRTY_MEM_BITS 30 /* 1G */ +#define PAGE_SHIFT_4K 12 + +/* The memory slot index to track dirty pages */ +#define TEST_MEM_SLOT_INDEX 1 + +/* Default guest test virtual memory offset */ +#define DEFAULT_GUEST_TEST_MEM 0xc0000000 + +/* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */ +#define TEST_HOST_LOOP_N 32UL + +/* Interval for each host loop (ms) */ +#define TEST_HOST_LOOP_INTERVAL 10UL + +/* + * Ensure the vCPU is able to perform a reasonable number of writes in each + * iteration to provide a lower bound on coverage. + */ +#define TEST_MIN_WRITES_PER_ITERATION 0x100 + +/* Dirty bitmaps are always little endian, so we need to swap on big endian */ +#if defined(__s390x__) +# define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7) +# define test_bit_le(nr, addr) \ + test_bit((nr) ^ BITOP_LE_SWIZZLE, addr) +# define __set_bit_le(nr, addr) \ + __set_bit((nr) ^ BITOP_LE_SWIZZLE, addr) +# define __clear_bit_le(nr, addr) \ + __clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr) +# define __test_and_set_bit_le(nr, addr) \ + __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr) +# define __test_and_clear_bit_le(nr, addr) \ + __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr) +#else +# define test_bit_le test_bit +# define __set_bit_le __set_bit +# define __clear_bit_le __clear_bit +# define __test_and_set_bit_le __test_and_set_bit +# define __test_and_clear_bit_le __test_and_clear_bit +#endif + +#define TEST_DIRTY_RING_COUNT 65536 + +#define SIG_IPI SIGUSR1 + +/* + * 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 uint64_t guest_num_pages; +static uint64_t iteration; +static uint64_t nr_writes; +static bool vcpu_stop; + +/* + * 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; + +/* + * Continuously write to the first 8 bytes of a random pages within + * the testing memory region. + */ +static void guest_code(void) +{ + uint64_t addr; + +#ifdef __s390x__ + uint64_t i; + + /* + * On s390x, all pages of a 1M segment are initially marked as dirty + * when a page of the segment is written to for the very first time. + * To compensate this specialty in this test, we need to touch all + * pages during the first iteration. + */ + for (i = 0; i < guest_num_pages; i++) { + addr = guest_test_virt_mem + i * guest_page_size; + vcpu_arch_put_guest(*(uint64_t *)addr, READ_ONCE(iteration)); + nr_writes++; + } +#endif + + while (true) { + while (!READ_ONCE(vcpu_stop)) { + addr = guest_test_virt_mem; + addr += (guest_random_u64(&guest_rng) % guest_num_pages) + * guest_page_size; + addr = align_down(addr, host_page_size); + + vcpu_arch_put_guest(*(uint64_t *)addr, READ_ONCE(iteration)); + nr_writes++; + } + + GUEST_SYNC(1); + } +} + +/* Host variables */ +static bool host_quit; + +/* Points to the test VM memory region on which we track dirty logs */ +static void *host_test_mem; +static uint64_t host_num_pages; + +/* For statistics only */ +static uint64_t host_dirty_count; +static uint64_t host_clear_count; + +/* Whether dirty ring reset is requested, or finished */ +static sem_t sem_vcpu_stop; +static sem_t sem_vcpu_cont; + +/* + * This is updated by the vcpu thread to tell the host whether it's a + * ring-full event. It should only be read until a sem_wait() of + * sem_vcpu_stop and before vcpu continues to run. + */ +static bool dirty_ring_vcpu_ring_full; + +/* + * This is only used for verifying the dirty pages. Dirty ring has a very + * tricky case when the ring just got full, kvm will do userspace exit due to + * ring full. When that happens, the very last PFN is set but actually the + * data is not changed (the guest WRITE is not really applied yet), because + * we found that the dirty ring is full, refused to continue the vcpu, and + * recorded the dirty gfn with the old contents. + * + * For this specific case, it's safe to skip checking this pfn for this + * bit, because it's a redundant bit, and when the write happens later the bit + * will be set again. We use this variable to always keep track of the latest + * dirty gfn we've collected, so that if a mismatch of data found later in the + * verifying process, we let it pass. + */ +static uint64_t dirty_ring_last_page = -1ULL; + +/* + * In addition to the above, it is possible (especially if this + * test is run nested) for the above scenario to repeat multiple times: + * + * The following can happen: + * + * - L1 vCPU: Memory write is logged to PML but not committed. + * + * - L1 test thread: Ignores the write because its last dirty ring entry + * Resets the dirty ring which: + * - Resets the A/D bits in EPT + * - Issues tlb flush (invept), which is intercepted by L0 + * + * - L0: frees the whole nested ept mmu root as the response to invept, + * and thus ensures that when memory write is retried, it will fault again + * + * - L1 vCPU: Same memory write is logged to the PML but not committed again. + * + * - L1 test thread: Ignores the write because its last dirty ring entry (again) + * Resets the dirty ring which: + * - Resets the A/D bits in EPT (again) + * - Issues tlb flush (again) which is intercepted by L0 + * + * ... + * + * N times + * + * - L1 vCPU: Memory write is logged in the PML and then committed. + * Lots of other memory writes are logged and committed. + * ... + * + * - L1 test thread: Sees the memory write along with other memory writes + * in the dirty ring, and since the write is usually not + * the last entry in the dirty-ring and has a very outdated + * iteration, the test fails. + * + * + * Note that this is only possible when the write was the last log entry + * write during iteration N-1, thus remember last iteration last log entry + * and also don't fail when it is reported in the next iteration, together with + * an outdated iteration count. + */ +static uint64_t dirty_ring_prev_iteration_last_page; + +enum log_mode_t { + /* Only use KVM_GET_DIRTY_LOG for logging */ + LOG_MODE_DIRTY_LOG = 0, + + /* Use both KVM_[GET|CLEAR]_DIRTY_LOG for logging */ + LOG_MODE_CLEAR_LOG = 1, + + /* Use dirty ring for logging */ + LOG_MODE_DIRTY_RING = 2, + + LOG_MODE_NUM, + + /* Run all supported modes */ + LOG_MODE_ALL = LOG_MODE_NUM, +}; + +/* Mode of logging to test. Default is to run all supported modes */ +static enum log_mode_t host_log_mode_option = LOG_MODE_ALL; +/* Logging mode for current run */ +static enum log_mode_t host_log_mode; +static pthread_t vcpu_thread; +static uint32_t test_dirty_ring_count = TEST_DIRTY_RING_COUNT; + +static bool clear_log_supported(void) +{ + return kvm_has_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2); +} + +static void clear_log_create_vm_done(struct kvm_vm *vm) +{ + u64 manual_caps; + + manual_caps = kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2); + TEST_ASSERT(manual_caps, "MANUAL_CAPS is zero!"); + manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | + KVM_DIRTY_LOG_INITIALLY_SET); + vm_enable_cap(vm, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, manual_caps); +} + +static void dirty_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, + void *bitmap, uint32_t num_pages, + uint32_t *unused) +{ + kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap); +} + +static void clear_log_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, + void *bitmap, uint32_t num_pages, + uint32_t *unused) +{ + kvm_vm_get_dirty_log(vcpu->vm, slot, bitmap); + kvm_vm_clear_dirty_log(vcpu->vm, slot, bitmap, 0, num_pages); +} + +/* Should only be called after a GUEST_SYNC */ +static void vcpu_handle_sync_stop(void) +{ + if (READ_ONCE(vcpu_stop)) { + sem_post(&sem_vcpu_stop); + sem_wait(&sem_vcpu_cont); + } +} + +static void default_after_vcpu_run(struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + + TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC, + "Invalid guest sync status: exit_reason=%s", + exit_reason_str(run->exit_reason)); + + vcpu_handle_sync_stop(); +} + +static bool dirty_ring_supported(void) +{ + return (kvm_has_cap(KVM_CAP_DIRTY_LOG_RING) || + kvm_has_cap(KVM_CAP_DIRTY_LOG_RING_ACQ_REL)); +} + +static void dirty_ring_create_vm_done(struct kvm_vm *vm) +{ + uint64_t pages; + uint32_t limit; + + /* + * We rely on vcpu exit due to full dirty ring state. Adjust + * the ring buffer size to ensure we're able to reach the + * full dirty ring state. + */ + pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3; + pages = vm_adjust_num_guest_pages(vm->mode, pages); + if (vm->page_size < getpagesize()) + pages = vm_num_host_pages(vm->mode, pages); + + limit = 1 << (31 - __builtin_clz(pages)); + test_dirty_ring_count = 1 << (31 - __builtin_clz(test_dirty_ring_count)); + test_dirty_ring_count = min(limit, test_dirty_ring_count); + pr_info("dirty ring count: 0x%x\n", test_dirty_ring_count); + + /* + * Switch to dirty ring mode after VM creation but before any + * of the vcpu creation. + */ + vm_enable_dirty_ring(vm, test_dirty_ring_count * + sizeof(struct kvm_dirty_gfn)); +} + +static inline bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn) +{ + return smp_load_acquire(&gfn->flags) == KVM_DIRTY_GFN_F_DIRTY; +} + +static inline void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn) +{ + smp_store_release(&gfn->flags, KVM_DIRTY_GFN_F_RESET); +} + +static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns, + int slot, void *bitmap, + uint32_t num_pages, uint32_t *fetch_index) +{ + struct kvm_dirty_gfn *cur; + uint32_t count = 0; + + while (true) { + cur = &dirty_gfns[*fetch_index % test_dirty_ring_count]; + if (!dirty_gfn_is_dirtied(cur)) + break; + TEST_ASSERT(cur->slot == slot, "Slot number didn't match: " + "%u != %u", cur->slot, slot); + TEST_ASSERT(cur->offset < num_pages, "Offset overflow: " + "0x%llx >= 0x%x", cur->offset, num_pages); + __set_bit_le(cur->offset, bitmap); + dirty_ring_last_page = cur->offset; + dirty_gfn_set_collected(cur); + (*fetch_index)++; + count++; + } + + return count; +} + +static void dirty_ring_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, + void *bitmap, uint32_t num_pages, + uint32_t *ring_buf_idx) +{ + uint32_t count, cleared; + + /* Only have one vcpu */ + count = dirty_ring_collect_one(vcpu_map_dirty_ring(vcpu), + slot, bitmap, num_pages, + ring_buf_idx); + + cleared = kvm_vm_reset_dirty_ring(vcpu->vm); + + /* + * Cleared pages should be the same as collected, as KVM is supposed to + * clear only the entries that have been harvested. + */ + TEST_ASSERT(cleared == count, "Reset dirty pages (%u) mismatch " + "with collected (%u)", cleared, count); +} + +static void dirty_ring_after_vcpu_run(struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + + /* A ucall-sync or ring-full event is allowed */ + if (get_ucall(vcpu, NULL) == UCALL_SYNC) { + vcpu_handle_sync_stop(); + } else if (run->exit_reason == KVM_EXIT_DIRTY_RING_FULL) { + WRITE_ONCE(dirty_ring_vcpu_ring_full, true); + vcpu_handle_sync_stop(); + } else { + TEST_ASSERT(false, "Invalid guest sync status: " + "exit_reason=%s", + exit_reason_str(run->exit_reason)); + } +} + +struct log_mode { + const char *name; + /* Return true if this mode is supported, otherwise false */ + bool (*supported)(void); + /* Hook when the vm creation is done (before vcpu creation) */ + void (*create_vm_done)(struct kvm_vm *vm); + /* Hook to collect the dirty pages into the bitmap provided */ + void (*collect_dirty_pages) (struct kvm_vcpu *vcpu, int slot, + void *bitmap, uint32_t num_pages, + uint32_t *ring_buf_idx); + /* Hook to call when after each vcpu run */ + void (*after_vcpu_run)(struct kvm_vcpu *vcpu); +} log_modes[LOG_MODE_NUM] = { + { + .name = "dirty-log", + .collect_dirty_pages = dirty_log_collect_dirty_pages, + .after_vcpu_run = default_after_vcpu_run, + }, + { + .name = "clear-log", + .supported = clear_log_supported, + .create_vm_done = clear_log_create_vm_done, + .collect_dirty_pages = clear_log_collect_dirty_pages, + .after_vcpu_run = default_after_vcpu_run, + }, + { + .name = "dirty-ring", + .supported = dirty_ring_supported, + .create_vm_done = dirty_ring_create_vm_done, + .collect_dirty_pages = dirty_ring_collect_dirty_pages, + .after_vcpu_run = dirty_ring_after_vcpu_run, + }, +}; + +static void log_modes_dump(void) +{ + int i; + + printf("all"); + for (i = 0; i < LOG_MODE_NUM; i++) + printf(", %s", log_modes[i].name); + printf("\n"); +} + +static bool log_mode_supported(void) +{ + struct log_mode *mode = &log_modes[host_log_mode]; + + if (mode->supported) + return mode->supported(); + + return true; +} + +static void log_mode_create_vm_done(struct kvm_vm *vm) +{ + struct log_mode *mode = &log_modes[host_log_mode]; + + if (mode->create_vm_done) + mode->create_vm_done(vm); +} + +static void log_mode_collect_dirty_pages(struct kvm_vcpu *vcpu, int slot, + void *bitmap, uint32_t num_pages, + uint32_t *ring_buf_idx) +{ + struct log_mode *mode = &log_modes[host_log_mode]; + + TEST_ASSERT(mode->collect_dirty_pages != NULL, + "collect_dirty_pages() is required for any log mode!"); + mode->collect_dirty_pages(vcpu, slot, bitmap, num_pages, ring_buf_idx); +} + +static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu) +{ + struct log_mode *mode = &log_modes[host_log_mode]; + + if (mode->after_vcpu_run) + mode->after_vcpu_run(vcpu); +} + +static void *vcpu_worker(void *data) +{ + struct kvm_vcpu *vcpu = data; + + sem_wait(&sem_vcpu_cont); + + while (!READ_ONCE(host_quit)) { + /* Let the guest dirty the random pages */ + vcpu_run(vcpu); + log_mode_after_vcpu_run(vcpu); + } + + return NULL; +} + +static void vm_dirty_log_verify(enum vm_guest_mode mode, unsigned long **bmap) +{ + uint64_t page, nr_dirty_pages = 0, nr_clean_pages = 0; + uint64_t step = vm_num_host_pages(mode, 1); + + for (page = 0; page < host_num_pages; page += step) { + uint64_t val = *(uint64_t *)(host_test_mem + page * host_page_size); + bool bmap0_dirty = __test_and_clear_bit_le(page, bmap[0]); + + /* + * Ensure both bitmaps are cleared, as a page can be written + * multiple times per iteration, i.e. can show up in both + * bitmaps, and the dirty ring is additive, i.e. doesn't purge + * bitmap entries from previous collections. + */ + if (__test_and_clear_bit_le(page, bmap[1]) || bmap0_dirty) { + nr_dirty_pages++; + + /* + * If the page is dirty, the value written to memory + * should be the current iteration number. + */ + if (val == iteration) + continue; + + if (host_log_mode == LOG_MODE_DIRTY_RING) { + /* + * The last page in the ring from previous + * iteration can be written with the value + * from the previous iteration, as the value to + * be written may be cached in a CPU register. + */ + if (page == dirty_ring_prev_iteration_last_page && + val == iteration - 1) + continue; + + /* + * Any value from a previous iteration is legal + * for the last entry, as the write may not yet + * have retired, i.e. the page may hold whatever + * it had before this iteration started. + */ + if (page == dirty_ring_last_page && + val < iteration) + continue; + } else if (!val && iteration == 1 && bmap0_dirty) { + /* + * When testing get+clear, the dirty bitmap + * starts with all bits set, and so the first + * iteration can observe a "dirty" page that + * was never written, but only in the first + * bitmap (collecting the bitmap also clears + * all dirty pages). + */ + continue; + } + + TEST_FAIL("Dirty page %lu value (%lu) != iteration (%lu) " + "(last = %lu, prev_last = %lu)", + page, val, iteration, dirty_ring_last_page, + dirty_ring_prev_iteration_last_page); + } else { + nr_clean_pages++; + /* + * If cleared, the value written can be any + * value smaller than the iteration number. + */ + TEST_ASSERT(val < iteration, + "Clear page %lu value (%lu) >= iteration (%lu) " + "(last = %lu, prev_last = %lu)", + page, val, iteration, dirty_ring_last_page, + dirty_ring_prev_iteration_last_page); + } + } + + pr_info("Iteration %2ld: dirty: %-6lu clean: %-6lu writes: %-6lu\n", + iteration, nr_dirty_pages, nr_clean_pages, nr_writes); + + host_dirty_count += nr_dirty_pages; + host_clear_count += nr_clean_pages; +} + +static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu, + uint64_t extra_mem_pages, void *guest_code) +{ + struct kvm_vm *vm; + + pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode)); + + vm = __vm_create(VM_SHAPE(mode), 1, extra_mem_pages); + + log_mode_create_vm_done(vm); + *vcpu = vm_vcpu_add(vm, 0, guest_code); + kvm_arch_vm_finalize_vcpus(vm); + return vm; +} + +struct test_params { + unsigned long iterations; + unsigned long interval; + uint64_t phys_offset; +}; + +static void run_test(enum vm_guest_mode mode, void *arg) +{ + struct test_params *p = arg; + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + unsigned long *bmap[2]; + uint32_t ring_buf_idx = 0; + int sem_val; + + if (!log_mode_supported()) { + print_skip("Log mode '%s' not supported", + log_modes[host_log_mode].name); + return; + } + + /* + * We reserve page table for 2 times of extra dirty mem which + * will definitely cover the original (1G+) test range. Here + * we do the calculation with 4K page size which is the + * smallest so the page number will be enough for all archs + * (e.g., 64K page size guest will need even less memory for + * page tables). + */ + vm = create_vm(mode, &vcpu, + 2ul << (DIRTY_MEM_BITS - PAGE_SHIFT_4K), guest_code); + + guest_page_size = vm->page_size; + /* + * A little more than 1G of guest page sized pages. Cover the + * case where the size is not aligned to 64 pages. + */ + guest_num_pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3; + guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages); + + host_page_size = getpagesize(); + host_num_pages = vm_num_host_pages(mode, guest_num_pages); + + if (!p->phys_offset) { + guest_test_phys_mem = (vm->max_gfn - guest_num_pages) * + guest_page_size; + guest_test_phys_mem = align_down(guest_test_phys_mem, host_page_size); + } else { + guest_test_phys_mem = p->phys_offset; + } + +#ifdef __s390x__ + /* Align to 1M (segment size) */ + guest_test_phys_mem = align_down(guest_test_phys_mem, 1 << 20); + + /* + * The workaround in guest_code() to write all pages prior to the first + * iteration isn't compatible with the dirty ring, as the dirty ring + * support relies on the vCPU to actually stop when vcpu_stop is set so + * that the vCPU doesn't hang waiting for the dirty ring to be emptied. + */ + TEST_ASSERT(host_log_mode != LOG_MODE_DIRTY_RING, + "Test needs to be updated to support s390 dirty ring"); +#endif + + pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem); + + bmap[0] = bitmap_zalloc(host_num_pages); + bmap[1] = bitmap_zalloc(host_num_pages); + + /* Add an extra memory slot for testing dirty logging */ + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, + guest_test_phys_mem, + TEST_MEM_SLOT_INDEX, + guest_num_pages, + KVM_MEM_LOG_DIRTY_PAGES); + + /* Do mapping for the dirty track memory slot */ + virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages); + + /* Cache the HVA pointer of the region */ + host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem); + + /* 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, guest_test_virt_mem); + sync_global_to_guest(vm, guest_num_pages); + + host_dirty_count = 0; + host_clear_count = 0; + WRITE_ONCE(host_quit, false); + + /* + * Ensure the previous iteration didn't leave a dangling semaphore, i.e. + * that the main task and vCPU worker were synchronized and completed + * verification of all iterations. + */ + sem_getvalue(&sem_vcpu_stop, &sem_val); + TEST_ASSERT_EQ(sem_val, 0); + sem_getvalue(&sem_vcpu_cont, &sem_val); + TEST_ASSERT_EQ(sem_val, 0); + + TEST_ASSERT_EQ(vcpu_stop, false); + + pthread_create(&vcpu_thread, NULL, vcpu_worker, vcpu); + + for (iteration = 1; iteration <= p->iterations; iteration++) { + unsigned long i; + + sync_global_to_guest(vm, iteration); + + WRITE_ONCE(nr_writes, 0); + sync_global_to_guest(vm, nr_writes); + + dirty_ring_prev_iteration_last_page = dirty_ring_last_page; + WRITE_ONCE(dirty_ring_vcpu_ring_full, false); + + sem_post(&sem_vcpu_cont); + + /* + * Let the vCPU run beyond the configured interval until it has + * performed the minimum number of writes. This verifies the + * guest is making forward progress, e.g. isn't stuck because + * of a KVM bug, and puts a firm floor on test coverage. + */ + for (i = 0; i < p->interval || nr_writes < TEST_MIN_WRITES_PER_ITERATION; i++) { + /* + * Sleep in 1ms chunks to keep the interval math simple + * and so that the test doesn't run too far beyond the + * specified interval. + */ + usleep(1000); + + sync_global_from_guest(vm, nr_writes); + + /* + * Reap dirty pages while the guest is running so that + * dirty ring full events are resolved, i.e. so that a + * larger interval doesn't always end up with a vCPU + * that's effectively blocked. Collecting while the + * guest is running also verifies KVM doesn't lose any + * state. + * + * For bitmap modes, KVM overwrites the entire bitmap, + * i.e. collecting the bitmaps is destructive. Collect + * the bitmap only on the first pass, otherwise this + * test would lose track of dirty pages. + */ + if (i && host_log_mode != LOG_MODE_DIRTY_RING) + continue; + + /* + * For the dirty ring, empty the ring on subsequent + * passes only if the ring was filled at least once, + * to verify KVM's handling of a full ring (emptying + * the ring on every pass would make it unlikely the + * vCPU would ever fill the fing). + */ + if (i && !READ_ONCE(dirty_ring_vcpu_ring_full)) + continue; + + log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX, + bmap[0], host_num_pages, + &ring_buf_idx); + } + + /* + * Stop the vCPU prior to collecting and verifying the dirty + * log. If the vCPU is allowed to run during collection, then + * pages that are written during this iteration may be missed, + * i.e. collected in the next iteration. And if the vCPU is + * writing memory during verification, pages that this thread + * sees as clean may be written with this iteration's value. + */ + WRITE_ONCE(vcpu_stop, true); + sync_global_to_guest(vm, vcpu_stop); + sem_wait(&sem_vcpu_stop); + + /* + * Clear vcpu_stop after the vCPU thread has acknowledge the + * stop request and is waiting, i.e. is definitely not running! + */ + WRITE_ONCE(vcpu_stop, false); + sync_global_to_guest(vm, vcpu_stop); + + /* + * Sync the number of writes performed before verification, the + * info will be printed along with the dirty/clean page counts. + */ + sync_global_from_guest(vm, nr_writes); + + /* + * NOTE: for dirty ring, it's possible that we didn't stop at + * GUEST_SYNC but instead we stopped because ring is full; + * that's okay too because ring full means we're only missing + * the flush of the last page, and since we handle the last + * page specially verification will succeed anyway. + */ + log_mode_collect_dirty_pages(vcpu, TEST_MEM_SLOT_INDEX, + bmap[1], host_num_pages, + &ring_buf_idx); + vm_dirty_log_verify(mode, bmap); + } + + WRITE_ONCE(host_quit, true); + sem_post(&sem_vcpu_cont); + + pthread_join(vcpu_thread, NULL); + + pr_info("Total bits checked: dirty (%lu), clear (%lu)\n", + host_dirty_count, host_clear_count); + + free(bmap[0]); + free(bmap[1]); + kvm_vm_free(vm); +} + +static void help(char *name) +{ + puts(""); + printf("usage: %s [-h] [-i iterations] [-I interval] " + "[-p offset] [-m mode]\n", name); + puts(""); + printf(" -c: hint to dirty ring size, in number of entries\n"); + printf(" (only useful for dirty-ring test; default: %"PRIu32")\n", + TEST_DIRTY_RING_COUNT); + printf(" -i: specify iteration counts (default: %"PRIu64")\n", + TEST_HOST_LOOP_N); + printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n", + TEST_HOST_LOOP_INTERVAL); + printf(" -p: specify guest physical test memory offset\n" + " Warning: a low offset can conflict with the loaded test code.\n"); + printf(" -M: specify the host logging mode " + "(default: run all log modes). Supported modes: \n\t"); + log_modes_dump(); + guest_modes_help(); + puts(""); + exit(0); +} + +int main(int argc, char *argv[]) +{ + struct test_params p = { + .iterations = TEST_HOST_LOOP_N, + .interval = TEST_HOST_LOOP_INTERVAL, + }; + int opt, i; + + sem_init(&sem_vcpu_stop, 0, 0); + sem_init(&sem_vcpu_cont, 0, 0); + + guest_modes_append_default(); + + while ((opt = getopt(argc, argv, "c:hi:I:p:m:M:")) != -1) { + switch (opt) { + case 'c': + test_dirty_ring_count = strtol(optarg, NULL, 10); + break; + case 'i': + p.iterations = strtol(optarg, NULL, 10); + break; + case 'I': + p.interval = strtol(optarg, NULL, 10); + break; + case 'p': + p.phys_offset = strtoull(optarg, NULL, 0); + break; + case 'm': + guest_modes_cmdline(optarg); + break; + case 'M': + if (!strcmp(optarg, "all")) { + host_log_mode_option = LOG_MODE_ALL; + break; + } + for (i = 0; i < LOG_MODE_NUM; i++) { + if (!strcmp(optarg, log_modes[i].name)) { + pr_info("Setting log mode to: '%s'\n", + optarg); + host_log_mode_option = i; + break; + } + } + if (i == LOG_MODE_NUM) { + printf("Log mode '%s' invalid. Please choose " + "from: ", optarg); + log_modes_dump(); + exit(1); + } + break; + case 'h': + default: + help(argv[0]); + break; + } + } + + TEST_ASSERT(p.iterations > 0, "Iterations must be greater than zero"); + TEST_ASSERT(p.interval > 0, "Interval must be greater than zero"); + + pr_info("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n", + p.iterations, p.interval); + + if (host_log_mode_option == LOG_MODE_ALL) { + /* Run each log mode */ + for (i = 0; i < LOG_MODE_NUM; i++) { + pr_info("Testing Log Mode '%s'\n", log_modes[i].name); + host_log_mode = i; + for_each_guest_mode(run_test, &p); + } + } else { + host_log_mode = host_log_mode_option; + for_each_guest_mode(run_test, &p); + } + + return 0; +} |