| /* |
| * Postcopy migration for RAM |
| * |
| * Copyright 2013-2015 Red Hat, Inc. and/or its affiliates |
| * |
| * Authors: |
| * Dave Gilbert <dgilbert@redhat.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| * See the COPYING file in the top-level directory. |
| * |
| */ |
| |
| /* |
| * Postcopy is a migration technique where the execution flips from the |
| * source to the destination before all the data has been copied. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "exec/target_page.h" |
| #include "migration.h" |
| #include "qemu-file.h" |
| #include "savevm.h" |
| #include "postcopy-ram.h" |
| #include "ram.h" |
| #include "qapi/error.h" |
| #include "qemu/notify.h" |
| #include "qemu/rcu.h" |
| #include "sysemu/sysemu.h" |
| #include "sysemu/balloon.h" |
| #include "qemu/error-report.h" |
| #include "trace.h" |
| #include "hw/boards.h" |
| |
| /* Arbitrary limit on size of each discard command, |
| * keeps them around ~200 bytes |
| */ |
| #define MAX_DISCARDS_PER_COMMAND 12 |
| |
| struct PostcopyDiscardState { |
| const char *ramblock_name; |
| uint16_t cur_entry; |
| /* |
| * Start and length of a discard range (bytes) |
| */ |
| uint64_t start_list[MAX_DISCARDS_PER_COMMAND]; |
| uint64_t length_list[MAX_DISCARDS_PER_COMMAND]; |
| unsigned int nsentwords; |
| unsigned int nsentcmds; |
| }; |
| |
| static NotifierWithReturnList postcopy_notifier_list; |
| |
| void postcopy_infrastructure_init(void) |
| { |
| notifier_with_return_list_init(&postcopy_notifier_list); |
| } |
| |
| void postcopy_add_notifier(NotifierWithReturn *nn) |
| { |
| notifier_with_return_list_add(&postcopy_notifier_list, nn); |
| } |
| |
| void postcopy_remove_notifier(NotifierWithReturn *n) |
| { |
| notifier_with_return_remove(n); |
| } |
| |
| int postcopy_notify(enum PostcopyNotifyReason reason, Error **errp) |
| { |
| struct PostcopyNotifyData pnd; |
| pnd.reason = reason; |
| pnd.errp = errp; |
| |
| return notifier_with_return_list_notify(&postcopy_notifier_list, |
| &pnd); |
| } |
| |
| /* Postcopy needs to detect accesses to pages that haven't yet been copied |
| * across, and efficiently map new pages in, the techniques for doing this |
| * are target OS specific. |
| */ |
| #if defined(__linux__) |
| |
| #include <poll.h> |
| #include <sys/ioctl.h> |
| #include <sys/syscall.h> |
| #include <asm/types.h> /* for __u64 */ |
| #endif |
| |
| #if defined(__linux__) && defined(__NR_userfaultfd) && defined(CONFIG_EVENTFD) |
| #include <sys/eventfd.h> |
| #include <linux/userfaultfd.h> |
| |
| typedef struct PostcopyBlocktimeContext { |
| /* time when page fault initiated per vCPU */ |
| uint32_t *page_fault_vcpu_time; |
| /* page address per vCPU */ |
| uintptr_t *vcpu_addr; |
| uint32_t total_blocktime; |
| /* blocktime per vCPU */ |
| uint32_t *vcpu_blocktime; |
| /* point in time when last page fault was initiated */ |
| uint32_t last_begin; |
| /* number of vCPU are suspended */ |
| int smp_cpus_down; |
| uint64_t start_time; |
| |
| /* |
| * Handler for exit event, necessary for |
| * releasing whole blocktime_ctx |
| */ |
| Notifier exit_notifier; |
| } PostcopyBlocktimeContext; |
| |
| static void destroy_blocktime_context(struct PostcopyBlocktimeContext *ctx) |
| { |
| g_free(ctx->page_fault_vcpu_time); |
| g_free(ctx->vcpu_addr); |
| g_free(ctx->vcpu_blocktime); |
| g_free(ctx); |
| } |
| |
| static void migration_exit_cb(Notifier *n, void *data) |
| { |
| PostcopyBlocktimeContext *ctx = container_of(n, PostcopyBlocktimeContext, |
| exit_notifier); |
| destroy_blocktime_context(ctx); |
| } |
| |
| static struct PostcopyBlocktimeContext *blocktime_context_new(void) |
| { |
| MachineState *ms = MACHINE(qdev_get_machine()); |
| unsigned int smp_cpus = ms->smp.cpus; |
| PostcopyBlocktimeContext *ctx = g_new0(PostcopyBlocktimeContext, 1); |
| ctx->page_fault_vcpu_time = g_new0(uint32_t, smp_cpus); |
| ctx->vcpu_addr = g_new0(uintptr_t, smp_cpus); |
| ctx->vcpu_blocktime = g_new0(uint32_t, smp_cpus); |
| |
| ctx->exit_notifier.notify = migration_exit_cb; |
| ctx->start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); |
| qemu_add_exit_notifier(&ctx->exit_notifier); |
| return ctx; |
| } |
| |
| static uint32List *get_vcpu_blocktime_list(PostcopyBlocktimeContext *ctx) |
| { |
| MachineState *ms = MACHINE(qdev_get_machine()); |
| uint32List *list = NULL, *entry = NULL; |
| int i; |
| |
| for (i = ms->smp.cpus - 1; i >= 0; i--) { |
| entry = g_new0(uint32List, 1); |
| entry->value = ctx->vcpu_blocktime[i]; |
| entry->next = list; |
| list = entry; |
| } |
| |
| return list; |
| } |
| |
| /* |
| * This function just populates MigrationInfo from postcopy's |
| * blocktime context. It will not populate MigrationInfo, |
| * unless postcopy-blocktime capability was set. |
| * |
| * @info: pointer to MigrationInfo to populate |
| */ |
| void fill_destination_postcopy_migration_info(MigrationInfo *info) |
| { |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| PostcopyBlocktimeContext *bc = mis->blocktime_ctx; |
| |
| if (!bc) { |
| return; |
| } |
| |
| info->has_postcopy_blocktime = true; |
| info->postcopy_blocktime = bc->total_blocktime; |
| info->has_postcopy_vcpu_blocktime = true; |
| info->postcopy_vcpu_blocktime = get_vcpu_blocktime_list(bc); |
| } |
| |
| static uint32_t get_postcopy_total_blocktime(void) |
| { |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| PostcopyBlocktimeContext *bc = mis->blocktime_ctx; |
| |
| if (!bc) { |
| return 0; |
| } |
| |
| return bc->total_blocktime; |
| } |
| |
| /** |
| * receive_ufd_features: check userfault fd features, to request only supported |
| * features in the future. |
| * |
| * Returns: true on success |
| * |
| * __NR_userfaultfd - should be checked before |
| * @features: out parameter will contain uffdio_api.features provided by kernel |
| * in case of success |
| */ |
| static bool receive_ufd_features(uint64_t *features) |
| { |
| struct uffdio_api api_struct = {0}; |
| int ufd; |
| bool ret = true; |
| |
| /* if we are here __NR_userfaultfd should exists */ |
| ufd = syscall(__NR_userfaultfd, O_CLOEXEC); |
| if (ufd == -1) { |
| error_report("%s: syscall __NR_userfaultfd failed: %s", __func__, |
| strerror(errno)); |
| return false; |
| } |
| |
| /* ask features */ |
| api_struct.api = UFFD_API; |
| api_struct.features = 0; |
| if (ioctl(ufd, UFFDIO_API, &api_struct)) { |
| error_report("%s: UFFDIO_API failed: %s", __func__, |
| strerror(errno)); |
| ret = false; |
| goto release_ufd; |
| } |
| |
| *features = api_struct.features; |
| |
| release_ufd: |
| close(ufd); |
| return ret; |
| } |
| |
| /** |
| * request_ufd_features: this function should be called only once on a newly |
| * opened ufd, subsequent calls will lead to error. |
| * |
| * Returns: true on succes |
| * |
| * @ufd: fd obtained from userfaultfd syscall |
| * @features: bit mask see UFFD_API_FEATURES |
| */ |
| static bool request_ufd_features(int ufd, uint64_t features) |
| { |
| struct uffdio_api api_struct = {0}; |
| uint64_t ioctl_mask; |
| |
| api_struct.api = UFFD_API; |
| api_struct.features = features; |
| if (ioctl(ufd, UFFDIO_API, &api_struct)) { |
| error_report("%s failed: UFFDIO_API failed: %s", __func__, |
| strerror(errno)); |
| return false; |
| } |
| |
| ioctl_mask = (__u64)1 << _UFFDIO_REGISTER | |
| (__u64)1 << _UFFDIO_UNREGISTER; |
| if ((api_struct.ioctls & ioctl_mask) != ioctl_mask) { |
| error_report("Missing userfault features: %" PRIx64, |
| (uint64_t)(~api_struct.ioctls & ioctl_mask)); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis) |
| { |
| uint64_t asked_features = 0; |
| static uint64_t supported_features; |
| |
| /* |
| * it's not possible to |
| * request UFFD_API twice per one fd |
| * userfault fd features is persistent |
| */ |
| if (!supported_features) { |
| if (!receive_ufd_features(&supported_features)) { |
| error_report("%s failed", __func__); |
| return false; |
| } |
| } |
| |
| #ifdef UFFD_FEATURE_THREAD_ID |
| if (migrate_postcopy_blocktime() && mis && |
| UFFD_FEATURE_THREAD_ID & supported_features) { |
| /* kernel supports that feature */ |
| /* don't create blocktime_context if it exists */ |
| if (!mis->blocktime_ctx) { |
| mis->blocktime_ctx = blocktime_context_new(); |
| } |
| |
| asked_features |= UFFD_FEATURE_THREAD_ID; |
| } |
| #endif |
| |
| /* |
| * request features, even if asked_features is 0, due to |
| * kernel expects UFFD_API before UFFDIO_REGISTER, per |
| * userfault file descriptor |
| */ |
| if (!request_ufd_features(ufd, asked_features)) { |
| error_report("%s failed: features %" PRIu64, __func__, |
| asked_features); |
| return false; |
| } |
| |
| if (getpagesize() != ram_pagesize_summary()) { |
| bool have_hp = false; |
| /* We've got a huge page */ |
| #ifdef UFFD_FEATURE_MISSING_HUGETLBFS |
| have_hp = supported_features & UFFD_FEATURE_MISSING_HUGETLBFS; |
| #endif |
| if (!have_hp) { |
| error_report("Userfault on this host does not support huge pages"); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /* Callback from postcopy_ram_supported_by_host block iterator. |
| */ |
| static int test_ramblock_postcopiable(RAMBlock *rb, void *opaque) |
| { |
| const char *block_name = qemu_ram_get_idstr(rb); |
| ram_addr_t length = qemu_ram_get_used_length(rb); |
| size_t pagesize = qemu_ram_pagesize(rb); |
| |
| if (length % pagesize) { |
| error_report("Postcopy requires RAM blocks to be a page size multiple," |
| " block %s is 0x" RAM_ADDR_FMT " bytes with a " |
| "page size of 0x%zx", block_name, length, pagesize); |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * Note: This has the side effect of munlock'ing all of RAM, that's |
| * normally fine since if the postcopy succeeds it gets turned back on at the |
| * end. |
| */ |
| bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) |
| { |
| long pagesize = getpagesize(); |
| int ufd = -1; |
| bool ret = false; /* Error unless we change it */ |
| void *testarea = NULL; |
| struct uffdio_register reg_struct; |
| struct uffdio_range range_struct; |
| uint64_t feature_mask; |
| Error *local_err = NULL; |
| |
| if (qemu_target_page_size() > pagesize) { |
| error_report("Target page size bigger than host page size"); |
| goto out; |
| } |
| |
| ufd = syscall(__NR_userfaultfd, O_CLOEXEC); |
| if (ufd == -1) { |
| error_report("%s: userfaultfd not available: %s", __func__, |
| strerror(errno)); |
| goto out; |
| } |
| |
| /* Give devices a chance to object */ |
| if (postcopy_notify(POSTCOPY_NOTIFY_PROBE, &local_err)) { |
| error_report_err(local_err); |
| goto out; |
| } |
| |
| /* Version and features check */ |
| if (!ufd_check_and_apply(ufd, mis)) { |
| goto out; |
| } |
| |
| /* We don't support postcopy with shared RAM yet */ |
| if (foreach_not_ignored_block(test_ramblock_postcopiable, NULL)) { |
| goto out; |
| } |
| |
| /* |
| * userfault and mlock don't go together; we'll put it back later if |
| * it was enabled. |
| */ |
| if (munlockall()) { |
| error_report("%s: munlockall: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| |
| /* |
| * We need to check that the ops we need are supported on anon memory |
| * To do that we need to register a chunk and see the flags that |
| * are returned. |
| */ |
| testarea = mmap(NULL, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | |
| MAP_ANONYMOUS, -1, 0); |
| if (testarea == MAP_FAILED) { |
| error_report("%s: Failed to map test area: %s", __func__, |
| strerror(errno)); |
| goto out; |
| } |
| g_assert(((size_t)testarea & (pagesize-1)) == 0); |
| |
| reg_struct.range.start = (uintptr_t)testarea; |
| reg_struct.range.len = pagesize; |
| reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING; |
| |
| if (ioctl(ufd, UFFDIO_REGISTER, ®_struct)) { |
| error_report("%s userfault register: %s", __func__, strerror(errno)); |
| goto out; |
| } |
| |
| range_struct.start = (uintptr_t)testarea; |
| range_struct.len = pagesize; |
| if (ioctl(ufd, UFFDIO_UNREGISTER, &range_struct)) { |
| error_report("%s userfault unregister: %s", __func__, strerror(errno)); |
| goto out; |
| } |
| |
| feature_mask = (__u64)1 << _UFFDIO_WAKE | |
| (__u64)1 << _UFFDIO_COPY | |
| (__u64)1 << _UFFDIO_ZEROPAGE; |
| if ((reg_struct.ioctls & feature_mask) != feature_mask) { |
| error_report("Missing userfault map features: %" PRIx64, |
| (uint64_t)(~reg_struct.ioctls & feature_mask)); |
| goto out; |
| } |
| |
| /* Success! */ |
| ret = true; |
| out: |
| if (testarea) { |
| munmap(testarea, pagesize); |
| } |
| if (ufd != -1) { |
| close(ufd); |
| } |
| return ret; |
| } |
| |
| /* |
| * Setup an area of RAM so that it *can* be used for postcopy later; this |
| * must be done right at the start prior to pre-copy. |
| * opaque should be the MIS. |
| */ |
| static int init_range(RAMBlock *rb, void *opaque) |
| { |
| const char *block_name = qemu_ram_get_idstr(rb); |
| void *host_addr = qemu_ram_get_host_addr(rb); |
| ram_addr_t offset = qemu_ram_get_offset(rb); |
| ram_addr_t length = qemu_ram_get_used_length(rb); |
| trace_postcopy_init_range(block_name, host_addr, offset, length); |
| |
| /* |
| * We need the whole of RAM to be truly empty for postcopy, so things |
| * like ROMs and any data tables built during init must be zero'd |
| * - we're going to get the copy from the source anyway. |
| * (Precopy will just overwrite this data, so doesn't need the discard) |
| */ |
| if (ram_discard_range(block_name, 0, length)) { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * At the end of migration, undo the effects of init_range |
| * opaque should be the MIS. |
| */ |
| static int cleanup_range(RAMBlock *rb, void *opaque) |
| { |
| const char *block_name = qemu_ram_get_idstr(rb); |
| void *host_addr = qemu_ram_get_host_addr(rb); |
| ram_addr_t offset = qemu_ram_get_offset(rb); |
| ram_addr_t length = qemu_ram_get_used_length(rb); |
| MigrationIncomingState *mis = opaque; |
| struct uffdio_range range_struct; |
| trace_postcopy_cleanup_range(block_name, host_addr, offset, length); |
| |
| /* |
| * We turned off hugepage for the precopy stage with postcopy enabled |
| * we can turn it back on now. |
| */ |
| qemu_madvise(host_addr, length, QEMU_MADV_HUGEPAGE); |
| |
| /* |
| * We can also turn off userfault now since we should have all the |
| * pages. It can be useful to leave it on to debug postcopy |
| * if you're not sure it's always getting every page. |
| */ |
| range_struct.start = (uintptr_t)host_addr; |
| range_struct.len = length; |
| |
| if (ioctl(mis->userfault_fd, UFFDIO_UNREGISTER, &range_struct)) { |
| error_report("%s: userfault unregister %s", __func__, strerror(errno)); |
| |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Initialise postcopy-ram, setting the RAM to a state where we can go into |
| * postcopy later; must be called prior to any precopy. |
| * called from arch_init's similarly named ram_postcopy_incoming_init |
| */ |
| int postcopy_ram_incoming_init(MigrationIncomingState *mis) |
| { |
| if (foreach_not_ignored_block(init_range, NULL)) { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Manage a single vote to the QEMU balloon inhibitor for all postcopy usage, |
| * last caller wins. |
| */ |
| static void postcopy_balloon_inhibit(bool state) |
| { |
| static bool cur_state = false; |
| |
| if (state != cur_state) { |
| qemu_balloon_inhibit(state); |
| cur_state = state; |
| } |
| } |
| |
| /* |
| * At the end of a migration where postcopy_ram_incoming_init was called. |
| */ |
| int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) |
| { |
| trace_postcopy_ram_incoming_cleanup_entry(); |
| |
| if (mis->have_fault_thread) { |
| Error *local_err = NULL; |
| |
| /* Let the fault thread quit */ |
| atomic_set(&mis->fault_thread_quit, 1); |
| postcopy_fault_thread_notify(mis); |
| trace_postcopy_ram_incoming_cleanup_join(); |
| qemu_thread_join(&mis->fault_thread); |
| |
| if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_END, &local_err)) { |
| error_report_err(local_err); |
| return -1; |
| } |
| |
| if (foreach_not_ignored_block(cleanup_range, mis)) { |
| return -1; |
| } |
| |
| trace_postcopy_ram_incoming_cleanup_closeuf(); |
| close(mis->userfault_fd); |
| close(mis->userfault_event_fd); |
| mis->have_fault_thread = false; |
| } |
| |
| postcopy_balloon_inhibit(false); |
| |
| if (enable_mlock) { |
| if (os_mlock() < 0) { |
| error_report("mlock: %s", strerror(errno)); |
| /* |
| * It doesn't feel right to fail at this point, we have a valid |
| * VM state. |
| */ |
| } |
| } |
| |
| postcopy_state_set(POSTCOPY_INCOMING_END); |
| |
| if (mis->postcopy_tmp_page) { |
| munmap(mis->postcopy_tmp_page, mis->largest_page_size); |
| mis->postcopy_tmp_page = NULL; |
| } |
| if (mis->postcopy_tmp_zero_page) { |
| munmap(mis->postcopy_tmp_zero_page, mis->largest_page_size); |
| mis->postcopy_tmp_zero_page = NULL; |
| } |
| trace_postcopy_ram_incoming_cleanup_blocktime( |
| get_postcopy_total_blocktime()); |
| |
| trace_postcopy_ram_incoming_cleanup_exit(); |
| return 0; |
| } |
| |
| /* |
| * Disable huge pages on an area |
| */ |
| static int nhp_range(RAMBlock *rb, void *opaque) |
| { |
| const char *block_name = qemu_ram_get_idstr(rb); |
| void *host_addr = qemu_ram_get_host_addr(rb); |
| ram_addr_t offset = qemu_ram_get_offset(rb); |
| ram_addr_t length = qemu_ram_get_used_length(rb); |
| trace_postcopy_nhp_range(block_name, host_addr, offset, length); |
| |
| /* |
| * Before we do discards we need to ensure those discards really |
| * do delete areas of the page, even if THP thinks a hugepage would |
| * be a good idea, so force hugepages off. |
| */ |
| qemu_madvise(host_addr, length, QEMU_MADV_NOHUGEPAGE); |
| |
| return 0; |
| } |
| |
| /* |
| * Userfault requires us to mark RAM as NOHUGEPAGE prior to discard |
| * however leaving it until after precopy means that most of the precopy |
| * data is still THPd |
| */ |
| int postcopy_ram_prepare_discard(MigrationIncomingState *mis) |
| { |
| if (foreach_not_ignored_block(nhp_range, mis)) { |
| return -1; |
| } |
| |
| postcopy_state_set(POSTCOPY_INCOMING_DISCARD); |
| |
| return 0; |
| } |
| |
| /* |
| * Mark the given area of RAM as requiring notification to unwritten areas |
| * Used as a callback on foreach_not_ignored_block. |
| * host_addr: Base of area to mark |
| * offset: Offset in the whole ram arena |
| * length: Length of the section |
| * opaque: MigrationIncomingState pointer |
| * Returns 0 on success |
| */ |
| static int ram_block_enable_notify(RAMBlock *rb, void *opaque) |
| { |
| MigrationIncomingState *mis = opaque; |
| struct uffdio_register reg_struct; |
| |
| reg_struct.range.start = (uintptr_t)qemu_ram_get_host_addr(rb); |
| reg_struct.range.len = qemu_ram_get_used_length(rb); |
| reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING; |
| |
| /* Now tell our userfault_fd that it's responsible for this area */ |
| if (ioctl(mis->userfault_fd, UFFDIO_REGISTER, ®_struct)) { |
| error_report("%s userfault register: %s", __func__, strerror(errno)); |
| return -1; |
| } |
| if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) { |
| error_report("%s userfault: Region doesn't support COPY", __func__); |
| return -1; |
| } |
| if (reg_struct.ioctls & ((__u64)1 << _UFFDIO_ZEROPAGE)) { |
| qemu_ram_set_uf_zeroable(rb); |
| } |
| |
| return 0; |
| } |
| |
| int postcopy_wake_shared(struct PostCopyFD *pcfd, |
| uint64_t client_addr, |
| RAMBlock *rb) |
| { |
| size_t pagesize = qemu_ram_pagesize(rb); |
| struct uffdio_range range; |
| int ret; |
| trace_postcopy_wake_shared(client_addr, qemu_ram_get_idstr(rb)); |
| range.start = client_addr & ~(pagesize - 1); |
| range.len = pagesize; |
| ret = ioctl(pcfd->fd, UFFDIO_WAKE, &range); |
| if (ret) { |
| error_report("%s: Failed to wake: %zx in %s (%s)", |
| __func__, (size_t)client_addr, qemu_ram_get_idstr(rb), |
| strerror(errno)); |
| } |
| return ret; |
| } |
| |
| /* |
| * Callback from shared fault handlers to ask for a page, |
| * the page must be specified by a RAMBlock and an offset in that rb |
| * Note: Only for use by shared fault handlers (in fault thread) |
| */ |
| int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, |
| uint64_t client_addr, uint64_t rb_offset) |
| { |
| size_t pagesize = qemu_ram_pagesize(rb); |
| uint64_t aligned_rbo = rb_offset & ~(pagesize - 1); |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| |
| trace_postcopy_request_shared_page(pcfd->idstr, qemu_ram_get_idstr(rb), |
| rb_offset); |
| if (ramblock_recv_bitmap_test_byte_offset(rb, aligned_rbo)) { |
| trace_postcopy_request_shared_page_present(pcfd->idstr, |
| qemu_ram_get_idstr(rb), rb_offset); |
| return postcopy_wake_shared(pcfd, client_addr, rb); |
| } |
| if (rb != mis->last_rb) { |
| mis->last_rb = rb; |
| migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb), |
| aligned_rbo, pagesize); |
| } else { |
| /* Save some space */ |
| migrate_send_rp_req_pages(mis, NULL, aligned_rbo, pagesize); |
| } |
| return 0; |
| } |
| |
| static int get_mem_fault_cpu_index(uint32_t pid) |
| { |
| CPUState *cpu_iter; |
| |
| CPU_FOREACH(cpu_iter) { |
| if (cpu_iter->thread_id == pid) { |
| trace_get_mem_fault_cpu_index(cpu_iter->cpu_index, pid); |
| return cpu_iter->cpu_index; |
| } |
| } |
| trace_get_mem_fault_cpu_index(-1, pid); |
| return -1; |
| } |
| |
| static uint32_t get_low_time_offset(PostcopyBlocktimeContext *dc) |
| { |
| int64_t start_time_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - |
| dc->start_time; |
| return start_time_offset < 1 ? 1 : start_time_offset & UINT32_MAX; |
| } |
| |
| /* |
| * This function is being called when pagefault occurs. It |
| * tracks down vCPU blocking time. |
| * |
| * @addr: faulted host virtual address |
| * @ptid: faulted process thread id |
| * @rb: ramblock appropriate to addr |
| */ |
| static void mark_postcopy_blocktime_begin(uintptr_t addr, uint32_t ptid, |
| RAMBlock *rb) |
| { |
| int cpu, already_received; |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| PostcopyBlocktimeContext *dc = mis->blocktime_ctx; |
| uint32_t low_time_offset; |
| |
| if (!dc || ptid == 0) { |
| return; |
| } |
| cpu = get_mem_fault_cpu_index(ptid); |
| if (cpu < 0) { |
| return; |
| } |
| |
| low_time_offset = get_low_time_offset(dc); |
| if (dc->vcpu_addr[cpu] == 0) { |
| atomic_inc(&dc->smp_cpus_down); |
| } |
| |
| atomic_xchg(&dc->last_begin, low_time_offset); |
| atomic_xchg(&dc->page_fault_vcpu_time[cpu], low_time_offset); |
| atomic_xchg(&dc->vcpu_addr[cpu], addr); |
| |
| /* check it here, not at the begining of the function, |
| * due to, check could accur early than bitmap_set in |
| * qemu_ufd_copy_ioctl */ |
| already_received = ramblock_recv_bitmap_test(rb, (void *)addr); |
| if (already_received) { |
| atomic_xchg(&dc->vcpu_addr[cpu], 0); |
| atomic_xchg(&dc->page_fault_vcpu_time[cpu], 0); |
| atomic_dec(&dc->smp_cpus_down); |
| } |
| trace_mark_postcopy_blocktime_begin(addr, dc, dc->page_fault_vcpu_time[cpu], |
| cpu, already_received); |
| } |
| |
| /* |
| * This function just provide calculated blocktime per cpu and trace it. |
| * Total blocktime is calculated in mark_postcopy_blocktime_end. |
| * |
| * |
| * Assume we have 3 CPU |
| * |
| * S1 E1 S1 E1 |
| * -----***********------------xxx***************------------------------> CPU1 |
| * |
| * S2 E2 |
| * ------------****************xxx---------------------------------------> CPU2 |
| * |
| * S3 E3 |
| * ------------------------****xxx********-------------------------------> CPU3 |
| * |
| * We have sequence S1,S2,E1,S3,S1,E2,E3,E1 |
| * S2,E1 - doesn't match condition due to sequence S1,S2,E1 doesn't include CPU3 |
| * S3,S1,E2 - sequence includes all CPUs, in this case overlap will be S1,E2 - |
| * it's a part of total blocktime. |
| * S1 - here is last_begin |
| * Legend of the picture is following: |
| * * - means blocktime per vCPU |
| * x - means overlapped blocktime (total blocktime) |
| * |
| * @addr: host virtual address |
| */ |
| static void mark_postcopy_blocktime_end(uintptr_t addr) |
| { |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| PostcopyBlocktimeContext *dc = mis->blocktime_ctx; |
| MachineState *ms = MACHINE(qdev_get_machine()); |
| unsigned int smp_cpus = ms->smp.cpus; |
| int i, affected_cpu = 0; |
| bool vcpu_total_blocktime = false; |
| uint32_t read_vcpu_time, low_time_offset; |
| |
| if (!dc) { |
| return; |
| } |
| |
| low_time_offset = get_low_time_offset(dc); |
| /* lookup cpu, to clear it, |
| * that algorithm looks straighforward, but it's not |
| * optimal, more optimal algorithm is keeping tree or hash |
| * where key is address value is a list of */ |
| for (i = 0; i < smp_cpus; i++) { |
| uint32_t vcpu_blocktime = 0; |
| |
| read_vcpu_time = atomic_fetch_add(&dc->page_fault_vcpu_time[i], 0); |
| if (atomic_fetch_add(&dc->vcpu_addr[i], 0) != addr || |
| read_vcpu_time == 0) { |
| continue; |
| } |
| atomic_xchg(&dc->vcpu_addr[i], 0); |
| vcpu_blocktime = low_time_offset - read_vcpu_time; |
| affected_cpu += 1; |
| /* we need to know is that mark_postcopy_end was due to |
| * faulted page, another possible case it's prefetched |
| * page and in that case we shouldn't be here */ |
| if (!vcpu_total_blocktime && |
| atomic_fetch_add(&dc->smp_cpus_down, 0) == smp_cpus) { |
| vcpu_total_blocktime = true; |
| } |
| /* continue cycle, due to one page could affect several vCPUs */ |
| dc->vcpu_blocktime[i] += vcpu_blocktime; |
| } |
| |
| atomic_sub(&dc->smp_cpus_down, affected_cpu); |
| if (vcpu_total_blocktime) { |
| dc->total_blocktime += low_time_offset - atomic_fetch_add( |
| &dc->last_begin, 0); |
| } |
| trace_mark_postcopy_blocktime_end(addr, dc, dc->total_blocktime, |
| affected_cpu); |
| } |
| |
| static bool postcopy_pause_fault_thread(MigrationIncomingState *mis) |
| { |
| trace_postcopy_pause_fault_thread(); |
| |
| qemu_sem_wait(&mis->postcopy_pause_sem_fault); |
| |
| trace_postcopy_pause_fault_thread_continued(); |
| |
| return true; |
| } |
| |
| /* |
| * Handle faults detected by the USERFAULT markings |
| */ |
| static void *postcopy_ram_fault_thread(void *opaque) |
| { |
| MigrationIncomingState *mis = opaque; |
| struct uffd_msg msg; |
| int ret; |
| size_t index; |
| RAMBlock *rb = NULL; |
| |
| trace_postcopy_ram_fault_thread_entry(); |
| rcu_register_thread(); |
| mis->last_rb = NULL; /* last RAMBlock we sent part of */ |
| qemu_sem_post(&mis->fault_thread_sem); |
| |
| struct pollfd *pfd; |
| size_t pfd_len = 2 + mis->postcopy_remote_fds->len; |
| |
| pfd = g_new0(struct pollfd, pfd_len); |
| |
| pfd[0].fd = mis->userfault_fd; |
| pfd[0].events = POLLIN; |
| pfd[1].fd = mis->userfault_event_fd; |
| pfd[1].events = POLLIN; /* Waiting for eventfd to go positive */ |
| trace_postcopy_ram_fault_thread_fds_core(pfd[0].fd, pfd[1].fd); |
| for (index = 0; index < mis->postcopy_remote_fds->len; index++) { |
| struct PostCopyFD *pcfd = &g_array_index(mis->postcopy_remote_fds, |
| struct PostCopyFD, index); |
| pfd[2 + index].fd = pcfd->fd; |
| pfd[2 + index].events = POLLIN; |
| trace_postcopy_ram_fault_thread_fds_extra(2 + index, pcfd->idstr, |
| pcfd->fd); |
| } |
| |
| while (true) { |
| ram_addr_t rb_offset; |
| int poll_result; |
| |
| /* |
| * We're mainly waiting for the kernel to give us a faulting HVA, |
| * however we can be told to quit via userfault_quit_fd which is |
| * an eventfd |
| */ |
| |
| poll_result = poll(pfd, pfd_len, -1 /* Wait forever */); |
| if (poll_result == -1) { |
| error_report("%s: userfault poll: %s", __func__, strerror(errno)); |
| break; |
| } |
| |
| if (!mis->to_src_file) { |
| /* |
| * Possibly someone tells us that the return path is |
| * broken already using the event. We should hold until |
| * the channel is rebuilt. |
| */ |
| if (postcopy_pause_fault_thread(mis)) { |
| mis->last_rb = NULL; |
| /* Continue to read the userfaultfd */ |
| } else { |
| error_report("%s: paused but don't allow to continue", |
| __func__); |
| break; |
| } |
| } |
| |
| if (pfd[1].revents) { |
| uint64_t tmp64 = 0; |
| |
| /* Consume the signal */ |
| if (read(mis->userfault_event_fd, &tmp64, 8) != 8) { |
| /* Nothing obviously nicer than posting this error. */ |
| error_report("%s: read() failed", __func__); |
| } |
| |
| if (atomic_read(&mis->fault_thread_quit)) { |
| trace_postcopy_ram_fault_thread_quit(); |
| break; |
| } |
| } |
| |
| if (pfd[0].revents) { |
| poll_result--; |
| ret = read(mis->userfault_fd, &msg, sizeof(msg)); |
| if (ret != sizeof(msg)) { |
| if (errno == EAGAIN) { |
| /* |
| * if a wake up happens on the other thread just after |
| * the poll, there is nothing to read. |
| */ |
| continue; |
| } |
| if (ret < 0) { |
| error_report("%s: Failed to read full userfault " |
| "message: %s", |
| __func__, strerror(errno)); |
| break; |
| } else { |
| error_report("%s: Read %d bytes from userfaultfd " |
| "expected %zd", |
| __func__, ret, sizeof(msg)); |
| break; /* Lost alignment, don't know what we'd read next */ |
| } |
| } |
| if (msg.event != UFFD_EVENT_PAGEFAULT) { |
| error_report("%s: Read unexpected event %ud from userfaultfd", |
| __func__, msg.event); |
| continue; /* It's not a page fault, shouldn't happen */ |
| } |
| |
| rb = qemu_ram_block_from_host( |
| (void *)(uintptr_t)msg.arg.pagefault.address, |
| true, &rb_offset); |
| if (!rb) { |
| error_report("postcopy_ram_fault_thread: Fault outside guest: %" |
| PRIx64, (uint64_t)msg.arg.pagefault.address); |
| break; |
| } |
| |
| rb_offset &= ~(qemu_ram_pagesize(rb) - 1); |
| trace_postcopy_ram_fault_thread_request(msg.arg.pagefault.address, |
| qemu_ram_get_idstr(rb), |
| rb_offset, |
| msg.arg.pagefault.feat.ptid); |
| mark_postcopy_blocktime_begin( |
| (uintptr_t)(msg.arg.pagefault.address), |
| msg.arg.pagefault.feat.ptid, rb); |
| |
| retry: |
| /* |
| * Send the request to the source - we want to request one |
| * of our host page sizes (which is >= TPS) |
| */ |
| if (rb != mis->last_rb) { |
| mis->last_rb = rb; |
| ret = migrate_send_rp_req_pages(mis, |
| qemu_ram_get_idstr(rb), |
| rb_offset, |
| qemu_ram_pagesize(rb)); |
| } else { |
| /* Save some space */ |
| ret = migrate_send_rp_req_pages(mis, |
| NULL, |
| rb_offset, |
| qemu_ram_pagesize(rb)); |
| } |
| |
| if (ret) { |
| /* May be network failure, try to wait for recovery */ |
| if (ret == -EIO && postcopy_pause_fault_thread(mis)) { |
| /* We got reconnected somehow, try to continue */ |
| mis->last_rb = NULL; |
| goto retry; |
| } else { |
| /* This is a unavoidable fault */ |
| error_report("%s: migrate_send_rp_req_pages() get %d", |
| __func__, ret); |
| break; |
| } |
| } |
| } |
| |
| /* Now handle any requests from external processes on shared memory */ |
| /* TODO: May need to handle devices deregistering during postcopy */ |
| for (index = 2; index < pfd_len && poll_result; index++) { |
| if (pfd[index].revents) { |
| struct PostCopyFD *pcfd = |
| &g_array_index(mis->postcopy_remote_fds, |
| struct PostCopyFD, index - 2); |
| |
| poll_result--; |
| if (pfd[index].revents & POLLERR) { |
| error_report("%s: POLLERR on poll %zd fd=%d", |
| __func__, index, pcfd->fd); |
| pfd[index].events = 0; |
| continue; |
| } |
| |
| ret = read(pcfd->fd, &msg, sizeof(msg)); |
| if (ret != sizeof(msg)) { |
| if (errno == EAGAIN) { |
| /* |
| * if a wake up happens on the other thread just after |
| * the poll, there is nothing to read. |
| */ |
| continue; |
| } |
| if (ret < 0) { |
| error_report("%s: Failed to read full userfault " |
| "message: %s (shared) revents=%d", |
| __func__, strerror(errno), |
| pfd[index].revents); |
| /*TODO: Could just disable this sharer */ |
| break; |
| } else { |
| error_report("%s: Read %d bytes from userfaultfd " |
| "expected %zd (shared)", |
| __func__, ret, sizeof(msg)); |
| /*TODO: Could just disable this sharer */ |
| break; /*Lost alignment,don't know what we'd read next*/ |
| } |
| } |
| if (msg.event != UFFD_EVENT_PAGEFAULT) { |
| error_report("%s: Read unexpected event %ud " |
| "from userfaultfd (shared)", |
| __func__, msg.event); |
| continue; /* It's not a page fault, shouldn't happen */ |
| } |
| /* Call the device handler registered with us */ |
| ret = pcfd->handler(pcfd, &msg); |
| if (ret) { |
| error_report("%s: Failed to resolve shared fault on %zd/%s", |
| __func__, index, pcfd->idstr); |
| /* TODO: Fail? Disable this sharer? */ |
| } |
| } |
| } |
| } |
| rcu_unregister_thread(); |
| trace_postcopy_ram_fault_thread_exit(); |
| g_free(pfd); |
| return NULL; |
| } |
| |
| int postcopy_ram_enable_notify(MigrationIncomingState *mis) |
| { |
| /* Open the fd for the kernel to give us userfaults */ |
| mis->userfault_fd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); |
| if (mis->userfault_fd == -1) { |
| error_report("%s: Failed to open userfault fd: %s", __func__, |
| strerror(errno)); |
| return -1; |
| } |
| |
| /* |
| * Although the host check already tested the API, we need to |
| * do the check again as an ABI handshake on the new fd. |
| */ |
| if (!ufd_check_and_apply(mis->userfault_fd, mis)) { |
| return -1; |
| } |
| |
| /* Now an eventfd we use to tell the fault-thread to quit */ |
| mis->userfault_event_fd = eventfd(0, EFD_CLOEXEC); |
| if (mis->userfault_event_fd == -1) { |
| error_report("%s: Opening userfault_event_fd: %s", __func__, |
| strerror(errno)); |
| close(mis->userfault_fd); |
| return -1; |
| } |
| |
| qemu_sem_init(&mis->fault_thread_sem, 0); |
| qemu_thread_create(&mis->fault_thread, "postcopy/fault", |
| postcopy_ram_fault_thread, mis, QEMU_THREAD_JOINABLE); |
| qemu_sem_wait(&mis->fault_thread_sem); |
| qemu_sem_destroy(&mis->fault_thread_sem); |
| mis->have_fault_thread = true; |
| |
| /* Mark so that we get notified of accesses to unwritten areas */ |
| if (foreach_not_ignored_block(ram_block_enable_notify, mis)) { |
| error_report("ram_block_enable_notify failed"); |
| return -1; |
| } |
| |
| /* |
| * Ballooning can mark pages as absent while we're postcopying |
| * that would cause false userfaults. |
| */ |
| postcopy_balloon_inhibit(true); |
| |
| trace_postcopy_ram_enable_notify(); |
| |
| return 0; |
| } |
| |
| static int qemu_ufd_copy_ioctl(int userfault_fd, void *host_addr, |
| void *from_addr, uint64_t pagesize, RAMBlock *rb) |
| { |
| int ret; |
| if (from_addr) { |
| struct uffdio_copy copy_struct; |
| copy_struct.dst = (uint64_t)(uintptr_t)host_addr; |
| copy_struct.src = (uint64_t)(uintptr_t)from_addr; |
| copy_struct.len = pagesize; |
| copy_struct.mode = 0; |
| ret = ioctl(userfault_fd, UFFDIO_COPY, ©_struct); |
| } else { |
| struct uffdio_zeropage zero_struct; |
| zero_struct.range.start = (uint64_t)(uintptr_t)host_addr; |
| zero_struct.range.len = pagesize; |
| zero_struct.mode = 0; |
| ret = ioctl(userfault_fd, UFFDIO_ZEROPAGE, &zero_struct); |
| } |
| if (!ret) { |
| ramblock_recv_bitmap_set_range(rb, host_addr, |
| pagesize / qemu_target_page_size()); |
| mark_postcopy_blocktime_end((uintptr_t)host_addr); |
| |
| } |
| return ret; |
| } |
| |
| int postcopy_notify_shared_wake(RAMBlock *rb, uint64_t offset) |
| { |
| int i; |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| GArray *pcrfds = mis->postcopy_remote_fds; |
| |
| for (i = 0; i < pcrfds->len; i++) { |
| struct PostCopyFD *cur = &g_array_index(pcrfds, struct PostCopyFD, i); |
| int ret = cur->waker(cur, rb, offset); |
| if (ret) { |
| return ret; |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Place a host page (from) at (host) atomically |
| * returns 0 on success |
| */ |
| int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, |
| RAMBlock *rb) |
| { |
| size_t pagesize = qemu_ram_pagesize(rb); |
| |
| /* copy also acks to the kernel waking the stalled thread up |
| * TODO: We can inhibit that ack and only do it if it was requested |
| * which would be slightly cheaper, but we'd have to be careful |
| * of the order of updating our page state. |
| */ |
| if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, from, pagesize, rb)) { |
| int e = errno; |
| error_report("%s: %s copy host: %p from: %p (size: %zd)", |
| __func__, strerror(e), host, from, pagesize); |
| |
| return -e; |
| } |
| |
| trace_postcopy_place_page(host); |
| return postcopy_notify_shared_wake(rb, |
| qemu_ram_block_host_offset(rb, host)); |
| } |
| |
| /* |
| * Place a zero page at (host) atomically |
| * returns 0 on success |
| */ |
| int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, |
| RAMBlock *rb) |
| { |
| size_t pagesize = qemu_ram_pagesize(rb); |
| trace_postcopy_place_page_zero(host); |
| |
| /* Normal RAMBlocks can zero a page using UFFDIO_ZEROPAGE |
| * but it's not available for everything (e.g. hugetlbpages) |
| */ |
| if (qemu_ram_is_uf_zeroable(rb)) { |
| if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, pagesize, rb)) { |
| int e = errno; |
| error_report("%s: %s zero host: %p", |
| __func__, strerror(e), host); |
| |
| return -e; |
| } |
| return postcopy_notify_shared_wake(rb, |
| qemu_ram_block_host_offset(rb, |
| host)); |
| } else { |
| /* The kernel can't use UFFDIO_ZEROPAGE for hugepages */ |
| if (!mis->postcopy_tmp_zero_page) { |
| mis->postcopy_tmp_zero_page = mmap(NULL, mis->largest_page_size, |
| PROT_READ | PROT_WRITE, |
| MAP_PRIVATE | MAP_ANONYMOUS, |
| -1, 0); |
| if (mis->postcopy_tmp_zero_page == MAP_FAILED) { |
| int e = errno; |
| mis->postcopy_tmp_zero_page = NULL; |
| error_report("%s: %s mapping large zero page", |
| __func__, strerror(e)); |
| return -e; |
| } |
| memset(mis->postcopy_tmp_zero_page, '\0', mis->largest_page_size); |
| } |
| return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page, |
| rb); |
| } |
| } |
| |
| /* |
| * Returns a target page of memory that can be mapped at a later point in time |
| * using postcopy_place_page |
| * The same address is used repeatedly, postcopy_place_page just takes the |
| * backing page away. |
| * Returns: Pointer to allocated page |
| * |
| */ |
| void *postcopy_get_tmp_page(MigrationIncomingState *mis) |
| { |
| if (!mis->postcopy_tmp_page) { |
| mis->postcopy_tmp_page = mmap(NULL, mis->largest_page_size, |
| PROT_READ | PROT_WRITE, MAP_PRIVATE | |
| MAP_ANONYMOUS, -1, 0); |
| if (mis->postcopy_tmp_page == MAP_FAILED) { |
| mis->postcopy_tmp_page = NULL; |
| error_report("%s: %s", __func__, strerror(errno)); |
| return NULL; |
| } |
| } |
| |
| return mis->postcopy_tmp_page; |
| } |
| |
| #else |
| /* No target OS support, stubs just fail */ |
| void fill_destination_postcopy_migration_info(MigrationInfo *info) |
| { |
| } |
| |
| bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) |
| { |
| error_report("%s: No OS support", __func__); |
| return false; |
| } |
| |
| int postcopy_ram_incoming_init(MigrationIncomingState *mis) |
| { |
| error_report("postcopy_ram_incoming_init: No OS support"); |
| return -1; |
| } |
| |
| int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) |
| { |
| assert(0); |
| return -1; |
| } |
| |
| int postcopy_ram_prepare_discard(MigrationIncomingState *mis) |
| { |
| assert(0); |
| return -1; |
| } |
| |
| int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, |
| uint64_t client_addr, uint64_t rb_offset) |
| { |
| assert(0); |
| return -1; |
| } |
| |
| int postcopy_ram_enable_notify(MigrationIncomingState *mis) |
| { |
| assert(0); |
| return -1; |
| } |
| |
| int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, |
| RAMBlock *rb) |
| { |
| assert(0); |
| return -1; |
| } |
| |
| int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, |
| RAMBlock *rb) |
| { |
| assert(0); |
| return -1; |
| } |
| |
| void *postcopy_get_tmp_page(MigrationIncomingState *mis) |
| { |
| assert(0); |
| return NULL; |
| } |
| |
| int postcopy_wake_shared(struct PostCopyFD *pcfd, |
| uint64_t client_addr, |
| RAMBlock *rb) |
| { |
| assert(0); |
| return -1; |
| } |
| #endif |
| |
| /* ------------------------------------------------------------------------- */ |
| |
| void postcopy_fault_thread_notify(MigrationIncomingState *mis) |
| { |
| uint64_t tmp64 = 1; |
| |
| /* |
| * Wakeup the fault_thread. It's an eventfd that should currently |
| * be at 0, we're going to increment it to 1 |
| */ |
| if (write(mis->userfault_event_fd, &tmp64, 8) != 8) { |
| /* Not much we can do here, but may as well report it */ |
| error_report("%s: incrementing failed: %s", __func__, |
| strerror(errno)); |
| } |
| } |
| |
| /** |
| * postcopy_discard_send_init: Called at the start of each RAMBlock before |
| * asking to discard individual ranges. |
| * |
| * @ms: The current migration state. |
| * @offset: the bitmap offset of the named RAMBlock in the migration bitmap. |
| * @name: RAMBlock that discards will operate on. |
| */ |
| static PostcopyDiscardState pds = {0}; |
| void postcopy_discard_send_init(MigrationState *ms, const char *name) |
| { |
| pds.ramblock_name = name; |
| pds.cur_entry = 0; |
| pds.nsentwords = 0; |
| pds.nsentcmds = 0; |
| } |
| |
| /** |
| * postcopy_discard_send_range: Called by the bitmap code for each chunk to |
| * discard. May send a discard message, may just leave it queued to |
| * be sent later. |
| * |
| * @ms: Current migration state. |
| * @start,@length: a range of pages in the migration bitmap in the |
| * RAM block passed to postcopy_discard_send_init() (length=1 is one page) |
| */ |
| void postcopy_discard_send_range(MigrationState *ms, unsigned long start, |
| unsigned long length) |
| { |
| size_t tp_size = qemu_target_page_size(); |
| /* Convert to byte offsets within the RAM block */ |
| pds.start_list[pds.cur_entry] = start * tp_size; |
| pds.length_list[pds.cur_entry] = length * tp_size; |
| trace_postcopy_discard_send_range(pds.ramblock_name, start, length); |
| pds.cur_entry++; |
| pds.nsentwords++; |
| |
| if (pds.cur_entry == MAX_DISCARDS_PER_COMMAND) { |
| /* Full set, ship it! */ |
| qemu_savevm_send_postcopy_ram_discard(ms->to_dst_file, |
| pds.ramblock_name, |
| pds.cur_entry, |
| pds.start_list, |
| pds.length_list); |
| pds.nsentcmds++; |
| pds.cur_entry = 0; |
| } |
| } |
| |
| /** |
| * postcopy_discard_send_finish: Called at the end of each RAMBlock by the |
| * bitmap code. Sends any outstanding discard messages, frees the PDS |
| * |
| * @ms: Current migration state. |
| */ |
| void postcopy_discard_send_finish(MigrationState *ms) |
| { |
| /* Anything unsent? */ |
| if (pds.cur_entry) { |
| qemu_savevm_send_postcopy_ram_discard(ms->to_dst_file, |
| pds.ramblock_name, |
| pds.cur_entry, |
| pds.start_list, |
| pds.length_list); |
| pds.nsentcmds++; |
| } |
| |
| trace_postcopy_discard_send_finish(pds.ramblock_name, pds.nsentwords, |
| pds.nsentcmds); |
| } |
| |
| /* |
| * Current state of incoming postcopy; note this is not part of |
| * MigrationIncomingState since it's state is used during cleanup |
| * at the end as MIS is being freed. |
| */ |
| static PostcopyState incoming_postcopy_state; |
| |
| PostcopyState postcopy_state_get(void) |
| { |
| return atomic_mb_read(&incoming_postcopy_state); |
| } |
| |
| /* Set the state and return the old state */ |
| PostcopyState postcopy_state_set(PostcopyState new_state) |
| { |
| return atomic_xchg(&incoming_postcopy_state, new_state); |
| } |
| |
| /* Register a handler for external shared memory postcopy |
| * called on the destination. |
| */ |
| void postcopy_register_shared_ufd(struct PostCopyFD *pcfd) |
| { |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| |
| mis->postcopy_remote_fds = g_array_append_val(mis->postcopy_remote_fds, |
| *pcfd); |
| } |
| |
| /* Unregister a handler for external shared memory postcopy |
| */ |
| void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd) |
| { |
| guint i; |
| MigrationIncomingState *mis = migration_incoming_get_current(); |
| GArray *pcrfds = mis->postcopy_remote_fds; |
| |
| for (i = 0; i < pcrfds->len; i++) { |
| struct PostCopyFD *cur = &g_array_index(pcrfds, struct PostCopyFD, i); |
| if (cur->fd == pcfd->fd) { |
| mis->postcopy_remote_fds = g_array_remove_index(pcrfds, i); |
| return; |
| } |
| } |
| } |