/* * QEMU System Emulator * * Copyright (c) 2003-2008 Fabrice Bellard * Copyright (c) 2009-2015 Red Hat Inc * * Authors: * Juan Quintela * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include "hw/boards.h" #include "net/net.h" #include "migration.h" #include "migration/snapshot.h" #include "migration-stats.h" #include "migration/vmstate.h" #include "migration/misc.h" #include "migration/register.h" #include "migration/global_state.h" #include "migration/channel-block.h" #include "ram.h" #include "qemu-file.h" #include "savevm.h" #include "postcopy-ram.h" #include "qapi/error.h" #include "qapi/qapi-commands-migration.h" #include "qapi/clone-visitor.h" #include "qapi/qapi-builtin-visit.h" #include "qapi/qmp/qerror.h" #include "qemu/error-report.h" #include "sysemu/cpus.h" #include "exec/memory.h" #include "exec/target_page.h" #include "trace.h" #include "qemu/iov.h" #include "qemu/job.h" #include "qemu/main-loop.h" #include "block/snapshot.h" #include "qemu/cutils.h" #include "io/channel-buffer.h" #include "io/channel-file.h" #include "sysemu/replay.h" #include "sysemu/runstate.h" #include "sysemu/sysemu.h" #include "sysemu/xen.h" #include "migration/colo.h" #include "qemu/bitmap.h" #include "net/announce.h" #include "qemu/yank.h" #include "yank_functions.h" #include "sysemu/qtest.h" #include "options.h" const unsigned int postcopy_ram_discard_version; /* Subcommands for QEMU_VM_COMMAND */ enum qemu_vm_cmd { MIG_CMD_INVALID = 0, /* Must be 0 */ MIG_CMD_OPEN_RETURN_PATH, /* Tell the dest to open the Return path */ MIG_CMD_PING, /* Request a PONG on the RP */ MIG_CMD_POSTCOPY_ADVISE, /* Prior to any page transfers, just warn we might want to do PC */ MIG_CMD_POSTCOPY_LISTEN, /* Start listening for incoming pages as it's running. */ MIG_CMD_POSTCOPY_RUN, /* Start execution */ MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that were previously sent during precopy but are dirty. */ MIG_CMD_PACKAGED, /* Send a wrapped stream within this stream */ MIG_CMD_ENABLE_COLO, /* Enable COLO */ MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */ MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */ MIG_CMD_MAX }; #define MAX_VM_CMD_PACKAGED_SIZE UINT32_MAX static struct mig_cmd_args { ssize_t len; /* -1 = variable */ const char *name; } mig_cmd_args[] = { [MIG_CMD_INVALID] = { .len = -1, .name = "INVALID" }, [MIG_CMD_OPEN_RETURN_PATH] = { .len = 0, .name = "OPEN_RETURN_PATH" }, [MIG_CMD_PING] = { .len = sizeof(uint32_t), .name = "PING" }, [MIG_CMD_POSTCOPY_ADVISE] = { .len = -1, .name = "POSTCOPY_ADVISE" }, [MIG_CMD_POSTCOPY_LISTEN] = { .len = 0, .name = "POSTCOPY_LISTEN" }, [MIG_CMD_POSTCOPY_RUN] = { .len = 0, .name = "POSTCOPY_RUN" }, [MIG_CMD_POSTCOPY_RAM_DISCARD] = { .len = -1, .name = "POSTCOPY_RAM_DISCARD" }, [MIG_CMD_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" }, [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" }, [MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, [MIG_CMD_MAX] = { .len = -1, .name = "MAX" }, }; /* Note for MIG_CMD_POSTCOPY_ADVISE: * The format of arguments is depending on postcopy mode: * - postcopy RAM only * uint64_t host page size * uint64_t target page size * * - postcopy RAM and postcopy dirty bitmaps * format is the same as for postcopy RAM only * * - postcopy dirty bitmaps only * Nothing. Command length field is 0. * * Be careful: adding a new postcopy entity with some other parameters should * not break format self-description ability. Good way is to introduce some * generic extendable format with an exception for two old entities. */ /***********************************************************/ /* savevm/loadvm support */ static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable) { if (is_writable) { return qemu_file_new_output(QIO_CHANNEL(qio_channel_block_new(bs))); } else { return qemu_file_new_input(QIO_CHANNEL(qio_channel_block_new(bs))); } } /* QEMUFile timer support. * Not in qemu-file.c to not add qemu-timer.c as dependency to qemu-file.c */ void timer_put(QEMUFile *f, QEMUTimer *ts) { uint64_t expire_time; expire_time = timer_expire_time_ns(ts); qemu_put_be64(f, expire_time); } void timer_get(QEMUFile *f, QEMUTimer *ts) { uint64_t expire_time; expire_time = qemu_get_be64(f); if (expire_time != -1) { timer_mod_ns(ts, expire_time); } else { timer_del(ts); } } /* VMState timer support. * Not in vmstate.c to not add qemu-timer.c as dependency to vmstate.c */ static int get_timer(QEMUFile *f, void *pv, size_t size, const VMStateField *field) { QEMUTimer *v = pv; timer_get(f, v); return 0; } static int put_timer(QEMUFile *f, void *pv, size_t size, const VMStateField *field, JSONWriter *vmdesc) { QEMUTimer *v = pv; timer_put(f, v); return 0; } const VMStateInfo vmstate_info_timer = { .name = "timer", .get = get_timer, .put = put_timer, }; typedef struct CompatEntry { char idstr[256]; int instance_id; } CompatEntry; typedef struct SaveStateEntry { QTAILQ_ENTRY(SaveStateEntry) entry; char idstr[256]; uint32_t instance_id; int alias_id; int version_id; /* version id read from the stream */ int load_version_id; int section_id; /* section id read from the stream */ int load_section_id; const SaveVMHandlers *ops; const VMStateDescription *vmsd; void *opaque; CompatEntry *compat; int is_ram; } SaveStateEntry; typedef struct SaveState { QTAILQ_HEAD(, SaveStateEntry) handlers; SaveStateEntry *handler_pri_head[MIG_PRI_MAX + 1]; int global_section_id; uint32_t len; const char *name; uint32_t target_page_bits; uint32_t caps_count; MigrationCapability *capabilities; QemuUUID uuid; } SaveState; static SaveState savevm_state = { .handlers = QTAILQ_HEAD_INITIALIZER(savevm_state.handlers), .handler_pri_head = { [MIG_PRI_DEFAULT ... MIG_PRI_MAX] = NULL }, .global_section_id = 0, }; static bool should_validate_capability(int capability) { assert(capability >= 0 && capability < MIGRATION_CAPABILITY__MAX); /* Validate only new capabilities to keep compatibility. */ switch (capability) { case MIGRATION_CAPABILITY_X_IGNORE_SHARED: return true; default: return false; } } static uint32_t get_validatable_capabilities_count(void) { MigrationState *s = migrate_get_current(); uint32_t result = 0; int i; for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { if (should_validate_capability(i) && s->capabilities[i]) { result++; } } return result; } static int configuration_pre_save(void *opaque) { SaveState *state = opaque; const char *current_name = MACHINE_GET_CLASS(current_machine)->name; MigrationState *s = migrate_get_current(); int i, j; state->len = strlen(current_name); state->name = current_name; state->target_page_bits = qemu_target_page_bits(); state->caps_count = get_validatable_capabilities_count(); state->capabilities = g_renew(MigrationCapability, state->capabilities, state->caps_count); for (i = j = 0; i < MIGRATION_CAPABILITY__MAX; i++) { if (should_validate_capability(i) && s->capabilities[i]) { state->capabilities[j++] = i; } } state->uuid = qemu_uuid; return 0; } static int configuration_post_save(void *opaque) { SaveState *state = opaque; g_free(state->capabilities); state->capabilities = NULL; state->caps_count = 0; return 0; } static int configuration_pre_load(void *opaque) { SaveState *state = opaque; /* If there is no target-page-bits subsection it means the source * predates the variable-target-page-bits support and is using the * minimum possible value for this CPU. */ state->target_page_bits = qemu_target_page_bits_min(); return 0; } static bool configuration_validate_capabilities(SaveState *state) { bool ret = true; MigrationState *s = migrate_get_current(); unsigned long *source_caps_bm; int i; source_caps_bm = bitmap_new(MIGRATION_CAPABILITY__MAX); for (i = 0; i < state->caps_count; i++) { MigrationCapability capability = state->capabilities[i]; set_bit(capability, source_caps_bm); } for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { bool source_state, target_state; if (!should_validate_capability(i)) { continue; } source_state = test_bit(i, source_caps_bm); target_state = s->capabilities[i]; if (source_state != target_state) { error_report("Capability %s is %s, but received capability is %s", MigrationCapability_str(i), target_state ? "on" : "off", source_state ? "on" : "off"); ret = false; /* Don't break here to report all failed capabilities */ } } g_free(source_caps_bm); return ret; } static int configuration_post_load(void *opaque, int version_id) { SaveState *state = opaque; const char *current_name = MACHINE_GET_CLASS(current_machine)->name; int ret = 0; if (strncmp(state->name, current_name, state->len) != 0) { error_report("Machine type received is '%.*s' and local is '%s'", (int) state->len, state->name, current_name); ret = -EINVAL; goto out; } if (state->target_page_bits != qemu_target_page_bits()) { error_report("Received TARGET_PAGE_BITS is %d but local is %d", state->target_page_bits, qemu_target_page_bits()); ret = -EINVAL; goto out; } if (!configuration_validate_capabilities(state)) { ret = -EINVAL; goto out; } out: g_free((void *)state->name); state->name = NULL; state->len = 0; g_free(state->capabilities); state->capabilities = NULL; state->caps_count = 0; return ret; } static int get_capability(QEMUFile *f, void *pv, size_t size, const VMStateField *field) { MigrationCapability *capability = pv; char capability_str[UINT8_MAX + 1]; uint8_t len; int i; len = qemu_get_byte(f); qemu_get_buffer(f, (uint8_t *)capability_str, len); capability_str[len] = '\0'; for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) { if (!strcmp(MigrationCapability_str(i), capability_str)) { *capability = i; return 0; } } error_report("Received unknown capability %s", capability_str); return -EINVAL; } static int put_capability(QEMUFile *f, void *pv, size_t size, const VMStateField *field, JSONWriter *vmdesc) { MigrationCapability *capability = pv; const char *capability_str = MigrationCapability_str(*capability); size_t len = strlen(capability_str); assert(len <= UINT8_MAX); qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)capability_str, len); return 0; } static const VMStateInfo vmstate_info_capability = { .name = "capability", .get = get_capability, .put = put_capability, }; /* The target-page-bits subsection is present only if the * target page size is not the same as the default (ie the * minimum page size for a variable-page-size guest CPU). * If it is present then it contains the actual target page * bits for the machine, and migration will fail if the * two ends don't agree about it. */ static bool vmstate_target_page_bits_needed(void *opaque) { return qemu_target_page_bits() > qemu_target_page_bits_min(); } static const VMStateDescription vmstate_target_page_bits = { .name = "configuration/target-page-bits", .version_id = 1, .minimum_version_id = 1, .needed = vmstate_target_page_bits_needed, .fields = (VMStateField[]) { VMSTATE_UINT32(target_page_bits, SaveState), VMSTATE_END_OF_LIST() } }; static bool vmstate_capabilites_needed(void *opaque) { return get_validatable_capabilities_count() > 0; } static const VMStateDescription vmstate_capabilites = { .name = "configuration/capabilities", .version_id = 1, .minimum_version_id = 1, .needed = vmstate_capabilites_needed, .fields = (VMStateField[]) { VMSTATE_UINT32_V(caps_count, SaveState, 1), VMSTATE_VARRAY_UINT32_ALLOC(capabilities, SaveState, caps_count, 1, vmstate_info_capability, MigrationCapability), VMSTATE_END_OF_LIST() } }; static bool vmstate_uuid_needed(void *opaque) { return qemu_uuid_set && migrate_validate_uuid(); } static int vmstate_uuid_post_load(void *opaque, int version_id) { SaveState *state = opaque; char uuid_src[UUID_FMT_LEN + 1]; char uuid_dst[UUID_FMT_LEN + 1]; if (!qemu_uuid_set) { /* * It's warning because user might not know UUID in some cases, * e.g. load an old snapshot */ qemu_uuid_unparse(&state->uuid, uuid_src); warn_report("UUID is received %s, but local uuid isn't set", uuid_src); return 0; } if (!qemu_uuid_is_equal(&state->uuid, &qemu_uuid)) { qemu_uuid_unparse(&state->uuid, uuid_src); qemu_uuid_unparse(&qemu_uuid, uuid_dst); error_report("UUID received is %s and local is %s", uuid_src, uuid_dst); return -EINVAL; } return 0; } static const VMStateDescription vmstate_uuid = { .name = "configuration/uuid", .version_id = 1, .minimum_version_id = 1, .needed = vmstate_uuid_needed, .post_load = vmstate_uuid_post_load, .fields = (VMStateField[]) { VMSTATE_UINT8_ARRAY_V(uuid.data, SaveState, sizeof(QemuUUID), 1), VMSTATE_END_OF_LIST() } }; static const VMStateDescription vmstate_configuration = { .name = "configuration", .version_id = 1, .pre_load = configuration_pre_load, .post_load = configuration_post_load, .pre_save = configuration_pre_save, .post_save = configuration_post_save, .fields = (VMStateField[]) { VMSTATE_UINT32(len, SaveState), VMSTATE_VBUFFER_ALLOC_UINT32(name, SaveState, 0, NULL, len), VMSTATE_END_OF_LIST() }, .subsections = (const VMStateDescription *[]) { &vmstate_target_page_bits, &vmstate_capabilites, &vmstate_uuid, NULL } }; static void dump_vmstate_vmsd(FILE *out_file, const VMStateDescription *vmsd, int indent, bool is_subsection); static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field, int indent) { fprintf(out_file, "%*s{\n", indent, ""); indent += 2; fprintf(out_file, "%*s\"field\": \"%s\",\n", indent, "", field->name); fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", field->version_id); fprintf(out_file, "%*s\"field_exists\": %s,\n", indent, "", field->field_exists ? "true" : "false"); if (field->flags & VMS_ARRAY) { fprintf(out_file, "%*s\"num\": %d,\n", indent, "", field->num); } fprintf(out_file, "%*s\"size\": %zu", indent, "", field->size); if (field->vmsd != NULL) { fprintf(out_file, ",\n"); dump_vmstate_vmsd(out_file, field->vmsd, indent, false); } fprintf(out_file, "\n%*s}", indent - 2, ""); } static void dump_vmstate_vmss(FILE *out_file, const VMStateDescription **subsection, int indent) { if (*subsection != NULL) { dump_vmstate_vmsd(out_file, *subsection, indent, true); } } static void dump_vmstate_vmsd(FILE *out_file, const VMStateDescription *vmsd, int indent, bool is_subsection) { if (is_subsection) { fprintf(out_file, "%*s{\n", indent, ""); } else { fprintf(out_file, "%*s\"%s\": {\n", indent, "", "Description"); } indent += 2; fprintf(out_file, "%*s\"name\": \"%s\",\n", indent, "", vmsd->name); fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", vmsd->version_id); fprintf(out_file, "%*s\"minimum_version_id\": %d", indent, "", vmsd->minimum_version_id); if (vmsd->fields != NULL) { const VMStateField *field = vmsd->fields; bool first; fprintf(out_file, ",\n%*s\"Fields\": [\n", indent, ""); first = true; while (field->name != NULL) { if (field->flags & VMS_MUST_EXIST) { /* Ignore VMSTATE_VALIDATE bits; these don't get migrated */ field++; continue; } if (!first) { fprintf(out_file, ",\n"); } dump_vmstate_vmsf(out_file, field, indent + 2); field++; first = false; } assert(field->flags == VMS_END); fprintf(out_file, "\n%*s]", indent, ""); } if (vmsd->subsections != NULL) { const VMStateDescription **subsection = vmsd->subsections; bool first; fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, ""); first = true; while (*subsection != NULL) { if (!first) { fprintf(out_file, ",\n"); } dump_vmstate_vmss(out_file, subsection, indent + 2); subsection++; first = false; } fprintf(out_file, "\n%*s]", indent, ""); } fprintf(out_file, "\n%*s}", indent - 2, ""); } static void dump_machine_type(FILE *out_file) { MachineClass *mc; mc = MACHINE_GET_CLASS(current_machine); fprintf(out_file, " \"vmschkmachine\": {\n"); fprintf(out_file, " \"Name\": \"%s\"\n", mc->name); fprintf(out_file, " },\n"); } void dump_vmstate_json_to_file(FILE *out_file) { GSList *list, *elt; bool first; fprintf(out_file, "{\n"); dump_machine_type(out_file); first = true; list = object_class_get_list(TYPE_DEVICE, true); for (elt = list; elt; elt = elt->next) { DeviceClass *dc = OBJECT_CLASS_CHECK(DeviceClass, elt->data, TYPE_DEVICE); const char *name; int indent = 2; if (!dc->vmsd) { continue; } if (!first) { fprintf(out_file, ",\n"); } name = object_class_get_name(OBJECT_CLASS(dc)); fprintf(out_file, "%*s\"%s\": {\n", indent, "", name); indent += 2; fprintf(out_file, "%*s\"Name\": \"%s\",\n", indent, "", name); fprintf(out_file, "%*s\"version_id\": %d,\n", indent, "", dc->vmsd->version_id); fprintf(out_file, "%*s\"minimum_version_id\": %d,\n", indent, "", dc->vmsd->minimum_version_id); dump_vmstate_vmsd(out_file, dc->vmsd, indent, false); fprintf(out_file, "\n%*s}", indent - 2, ""); first = false; } fprintf(out_file, "\n}\n"); fclose(out_file); g_slist_free(list); } static uint32_t calculate_new_instance_id(const char *idstr) { SaveStateEntry *se; uint32_t instance_id = 0; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (strcmp(idstr, se->idstr) == 0 && instance_id <= se->instance_id) { instance_id = se->instance_id + 1; } } /* Make sure we never loop over without being noticed */ assert(instance_id != VMSTATE_INSTANCE_ID_ANY); return instance_id; } static int calculate_compat_instance_id(const char *idstr) { SaveStateEntry *se; int instance_id = 0; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->compat) { continue; } if (strcmp(idstr, se->compat->idstr) == 0 && instance_id <= se->compat->instance_id) { instance_id = se->compat->instance_id + 1; } } return instance_id; } static inline MigrationPriority save_state_priority(SaveStateEntry *se) { if (se->vmsd) { return se->vmsd->priority; } return MIG_PRI_DEFAULT; } static void savevm_state_handler_insert(SaveStateEntry *nse) { MigrationPriority priority = save_state_priority(nse); SaveStateEntry *se; int i; assert(priority <= MIG_PRI_MAX); for (i = priority - 1; i >= 0; i--) { se = savevm_state.handler_pri_head[i]; if (se != NULL) { assert(save_state_priority(se) < priority); break; } } if (i >= 0) { QTAILQ_INSERT_BEFORE(se, nse, entry); } else { QTAILQ_INSERT_TAIL(&savevm_state.handlers, nse, entry); } if (savevm_state.handler_pri_head[priority] == NULL) { savevm_state.handler_pri_head[priority] = nse; } } static void savevm_state_handler_remove(SaveStateEntry *se) { SaveStateEntry *next; MigrationPriority priority = save_state_priority(se); if (se == savevm_state.handler_pri_head[priority]) { next = QTAILQ_NEXT(se, entry); if (next != NULL && save_state_priority(next) == priority) { savevm_state.handler_pri_head[priority] = next; } else { savevm_state.handler_pri_head[priority] = NULL; } } QTAILQ_REMOVE(&savevm_state.handlers, se, entry); } /* TODO: Individual devices generally have very little idea about the rest of the system, so instance_id should be removed/replaced. Meanwhile pass -1 as instance_id if you do not already have a clearly distinguishing id for all instances of your device class. */ int register_savevm_live(const char *idstr, uint32_t instance_id, int version_id, const SaveVMHandlers *ops, void *opaque) { SaveStateEntry *se; se = g_new0(SaveStateEntry, 1); se->version_id = version_id; se->section_id = savevm_state.global_section_id++; se->ops = ops; se->opaque = opaque; se->vmsd = NULL; /* if this is a live_savem then set is_ram */ if (ops->save_setup != NULL) { se->is_ram = 1; } pstrcat(se->idstr, sizeof(se->idstr), idstr); if (instance_id == VMSTATE_INSTANCE_ID_ANY) { se->instance_id = calculate_new_instance_id(se->idstr); } else { se->instance_id = instance_id; } assert(!se->compat || se->instance_id == 0); savevm_state_handler_insert(se); return 0; } void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque) { SaveStateEntry *se, *new_se; char id[256] = ""; if (obj) { char *oid = vmstate_if_get_id(obj); if (oid) { pstrcpy(id, sizeof(id), oid); pstrcat(id, sizeof(id), "/"); g_free(oid); } } pstrcat(id, sizeof(id), idstr); QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) { if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) { savevm_state_handler_remove(se); g_free(se->compat); g_free(se); } } } /* * Perform some basic checks on vmsd's at registration * time. */ static void vmstate_check(const VMStateDescription *vmsd) { const VMStateField *field = vmsd->fields; const VMStateDescription **subsection = vmsd->subsections; if (field) { while (field->name) { if (field->flags & (VMS_STRUCT | VMS_VSTRUCT)) { /* Recurse to sub structures */ vmstate_check(field->vmsd); } /* Carry on */ field++; } /* Check for the end of field list canary */ if (field->flags != VMS_END) { error_report("VMSTATE not ending with VMS_END: %s", vmsd->name); g_assert_not_reached(); } } while (subsection && *subsection) { /* * The name of a subsection should start with the name of the * current object. */ assert(!strncmp(vmsd->name, (*subsection)->name, strlen(vmsd->name))); vmstate_check(*subsection); subsection++; } } int vmstate_register_with_alias_id(VMStateIf *obj, uint32_t instance_id, const VMStateDescription *vmsd, void *opaque, int alias_id, int required_for_version, Error **errp) { SaveStateEntry *se; /* If this triggers, alias support can be dropped for the vmsd. */ assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id); se = g_new0(SaveStateEntry, 1); se->version_id = vmsd->version_id; se->section_id = savevm_state.global_section_id++; se->opaque = opaque; se->vmsd = vmsd; se->alias_id = alias_id; if (obj) { char *id = vmstate_if_get_id(obj); if (id) { if (snprintf(se->idstr, sizeof(se->idstr), "%s/", id) >= sizeof(se->idstr)) { error_setg(errp, "Path too long for VMState (%s)", id); g_free(id); g_free(se); return -1; } g_free(id); se->compat = g_new0(CompatEntry, 1); pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name); se->compat->instance_id = instance_id == VMSTATE_INSTANCE_ID_ANY ? calculate_compat_instance_id(vmsd->name) : instance_id; instance_id = VMSTATE_INSTANCE_ID_ANY; } } pstrcat(se->idstr, sizeof(se->idstr), vmsd->name); if (instance_id == VMSTATE_INSTANCE_ID_ANY) { se->instance_id = calculate_new_instance_id(se->idstr); } else { se->instance_id = instance_id; } /* Perform a recursive sanity check during the test runs */ if (qtest_enabled()) { vmstate_check(vmsd); } assert(!se->compat || se->instance_id == 0); savevm_state_handler_insert(se); return 0; } void vmstate_unregister(VMStateIf *obj, const VMStateDescription *vmsd, void *opaque) { SaveStateEntry *se, *new_se; QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) { if (se->vmsd == vmsd && se->opaque == opaque) { savevm_state_handler_remove(se); g_free(se->compat); g_free(se); } } } static int vmstate_load(QEMUFile *f, SaveStateEntry *se) { trace_vmstate_load(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); if (!se->vmsd) { /* Old style */ return se->ops->load_state(f, se->opaque, se->load_version_id); } return vmstate_load_state(f, se->vmsd, se->opaque, se->load_version_id); } static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc) { uint64_t old_offset = qemu_file_transferred_fast(f); se->ops->save_state(f, se->opaque); uint64_t size = qemu_file_transferred_fast(f) - old_offset; if (vmdesc) { json_writer_int64(vmdesc, "size", size); json_writer_start_array(vmdesc, "fields"); json_writer_start_object(vmdesc, NULL); json_writer_str(vmdesc, "name", "data"); json_writer_int64(vmdesc, "size", size); json_writer_str(vmdesc, "type", "buffer"); json_writer_end_object(vmdesc); json_writer_end_array(vmdesc); } } /* * Write the header for device section (QEMU_VM_SECTION START/END/PART/FULL) */ static void save_section_header(QEMUFile *f, SaveStateEntry *se, uint8_t section_type) { qemu_put_byte(f, section_type); qemu_put_be32(f, se->section_id); if (section_type == QEMU_VM_SECTION_FULL || section_type == QEMU_VM_SECTION_START) { /* ID string */ size_t len = strlen(se->idstr); qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)se->idstr, len); qemu_put_be32(f, se->instance_id); qemu_put_be32(f, se->version_id); } } /* * Write a footer onto device sections that catches cases misformatted device * sections. */ static void save_section_footer(QEMUFile *f, SaveStateEntry *se) { if (migrate_get_current()->send_section_footer) { qemu_put_byte(f, QEMU_VM_SECTION_FOOTER); qemu_put_be32(f, se->section_id); } } static int vmstate_save(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc) { int ret; if ((!se->ops || !se->ops->save_state) && !se->vmsd) { return 0; } if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) { trace_savevm_section_skip(se->idstr, se->section_id); return 0; } trace_savevm_section_start(se->idstr, se->section_id); save_section_header(f, se, QEMU_VM_SECTION_FULL); if (vmdesc) { json_writer_start_object(vmdesc, NULL); json_writer_str(vmdesc, "name", se->idstr); json_writer_int64(vmdesc, "instance_id", se->instance_id); } trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); if (!se->vmsd) { vmstate_save_old_style(f, se, vmdesc); } else { ret = vmstate_save_state(f, se->vmsd, se->opaque, vmdesc); if (ret) { return ret; } } trace_savevm_section_end(se->idstr, se->section_id, 0); save_section_footer(f, se); if (vmdesc) { json_writer_end_object(vmdesc); } return 0; } /** * qemu_savevm_command_send: Send a 'QEMU_VM_COMMAND' type element with the * command and associated data. * * @f: File to send command on * @command: Command type to send * @len: Length of associated data * @data: Data associated with command. */ static void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, uint16_t len, uint8_t *data) { trace_savevm_command_send(command, len); qemu_put_byte(f, QEMU_VM_COMMAND); qemu_put_be16(f, (uint16_t)command); qemu_put_be16(f, len); qemu_put_buffer(f, data, len); qemu_fflush(f); } void qemu_savevm_send_colo_enable(QEMUFile *f) { trace_savevm_send_colo_enable(); qemu_savevm_command_send(f, MIG_CMD_ENABLE_COLO, 0, NULL); } void qemu_savevm_send_ping(QEMUFile *f, uint32_t value) { uint32_t buf; trace_savevm_send_ping(value); buf = cpu_to_be32(value); qemu_savevm_command_send(f, MIG_CMD_PING, sizeof(value), (uint8_t *)&buf); } void qemu_savevm_send_open_return_path(QEMUFile *f) { trace_savevm_send_open_return_path(); qemu_savevm_command_send(f, MIG_CMD_OPEN_RETURN_PATH, 0, NULL); } /* We have a buffer of data to send; we don't want that all to be loaded * by the command itself, so the command contains just the length of the * extra buffer that we then send straight after it. * TODO: Must be a better way to organise that * * Returns: * 0 on success * -ve on error */ int qemu_savevm_send_packaged(QEMUFile *f, const uint8_t *buf, size_t len) { uint32_t tmp; if (len > MAX_VM_CMD_PACKAGED_SIZE) { error_report("%s: Unreasonably large packaged state: %zu", __func__, len); return -1; } tmp = cpu_to_be32(len); trace_qemu_savevm_send_packaged(); qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp); qemu_put_buffer(f, buf, len); return 0; } /* Send prior to any postcopy transfer */ void qemu_savevm_send_postcopy_advise(QEMUFile *f) { if (migrate_postcopy_ram()) { uint64_t tmp[2]; tmp[0] = cpu_to_be64(ram_pagesize_summary()); tmp[1] = cpu_to_be64(qemu_target_page_size()); trace_qemu_savevm_send_postcopy_advise(); qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 16, (uint8_t *)tmp); } else { qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 0, NULL); } } /* Sent prior to starting the destination running in postcopy, discard pages * that have already been sent but redirtied on the source. * CMD_POSTCOPY_RAM_DISCARD consist of: * byte version (0) * byte Length of name field (not including 0) * n x byte RAM block name * byte 0 terminator (just for safety) * n x Byte ranges within the named RAMBlock * be64 Start of the range * be64 Length * * name: RAMBlock name that these entries are part of * len: Number of page entries * start_list: 'len' addresses * length_list: 'len' addresses * */ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name, uint16_t len, uint64_t *start_list, uint64_t *length_list) { uint8_t *buf; uint16_t tmplen; uint16_t t; size_t name_len = strlen(name); trace_qemu_savevm_send_postcopy_ram_discard(name, len); assert(name_len < 256); buf = g_malloc0(1 + 1 + name_len + 1 + (8 + 8) * len); buf[0] = postcopy_ram_discard_version; buf[1] = name_len; memcpy(buf + 2, name, name_len); tmplen = 2 + name_len; buf[tmplen++] = '\0'; for (t = 0; t < len; t++) { stq_be_p(buf + tmplen, start_list[t]); tmplen += 8; stq_be_p(buf + tmplen, length_list[t]); tmplen += 8; } qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf); g_free(buf); } /* Get the destination into a state where it can receive postcopy data. */ void qemu_savevm_send_postcopy_listen(QEMUFile *f) { trace_savevm_send_postcopy_listen(); qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_LISTEN, 0, NULL); } /* Kick the destination into running */ void qemu_savevm_send_postcopy_run(QEMUFile *f) { trace_savevm_send_postcopy_run(); qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RUN, 0, NULL); } void qemu_savevm_send_postcopy_resume(QEMUFile *f) { trace_savevm_send_postcopy_resume(); qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RESUME, 0, NULL); } void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name) { size_t len; char buf[256]; trace_savevm_send_recv_bitmap(block_name); buf[0] = len = strlen(block_name); memcpy(buf + 1, block_name, len); qemu_savevm_command_send(f, MIG_CMD_RECV_BITMAP, len + 1, (uint8_t *)buf); } bool qemu_savevm_state_blocked(Error **errp) { SaveStateEntry *se; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->vmsd && se->vmsd->unmigratable) { error_setg(errp, "State blocked by non-migratable device '%s'", se->idstr); return true; } } return false; } void qemu_savevm_non_migratable_list(strList **reasons) { SaveStateEntry *se; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->vmsd && se->vmsd->unmigratable) { QAPI_LIST_PREPEND(*reasons, g_strdup_printf("non-migratable device: %s", se->idstr)); } } } void qemu_savevm_state_header(QEMUFile *f) { trace_savevm_state_header(); qemu_put_be32(f, QEMU_VM_FILE_MAGIC); qemu_put_be32(f, QEMU_VM_FILE_VERSION); if (migrate_get_current()->send_configuration) { qemu_put_byte(f, QEMU_VM_CONFIGURATION); vmstate_save_state(f, &vmstate_configuration, &savevm_state, 0); } } bool qemu_savevm_state_guest_unplug_pending(void) { SaveStateEntry *se; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->vmsd && se->vmsd->dev_unplug_pending && se->vmsd->dev_unplug_pending(se->opaque)) { return true; } } return false; } void qemu_savevm_state_setup(QEMUFile *f) { MigrationState *ms = migrate_get_current(); SaveStateEntry *se; Error *local_err = NULL; int ret; ms->vmdesc = json_writer_new(false); json_writer_start_object(ms->vmdesc, NULL); json_writer_int64(ms->vmdesc, "page_size", qemu_target_page_size()); json_writer_start_array(ms->vmdesc, "devices"); trace_savevm_state_setup(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->vmsd && se->vmsd->early_setup) { ret = vmstate_save(f, se, ms->vmdesc); if (ret) { qemu_file_set_error(f, ret); break; } continue; } if (!se->ops || !se->ops->save_setup) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } save_section_header(f, se, QEMU_VM_SECTION_START); ret = se->ops->save_setup(f, se->opaque); save_section_footer(f, se); if (ret < 0) { qemu_file_set_error(f, ret); break; } } if (precopy_notify(PRECOPY_NOTIFY_SETUP, &local_err)) { error_report_err(local_err); } } int qemu_savevm_state_resume_prepare(MigrationState *s) { SaveStateEntry *se; int ret; trace_savevm_state_resume_prepare(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->resume_prepare) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } ret = se->ops->resume_prepare(s, se->opaque); if (ret < 0) { return ret; } } return 0; } /* * this function has three return values: * negative: there was one error, and we have -errno. * 0 : We haven't finished, caller have to go again * 1 : We have finished, we can go to complete phase */ int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy) { SaveStateEntry *se; int ret = 1; trace_savevm_state_iterate(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->save_live_iterate) { continue; } if (se->ops->is_active && !se->ops->is_active(se->opaque)) { continue; } if (se->ops->is_active_iterate && !se->ops->is_active_iterate(se->opaque)) { continue; } /* * In the postcopy phase, any device that doesn't know how to * do postcopy should have saved it's state in the _complete * call that's already run, it might get confused if we call * iterate afterwards. */ if (postcopy && !(se->ops->has_postcopy && se->ops->has_postcopy(se->opaque))) { continue; } if (migration_rate_exceeded(f)) { return 0; } trace_savevm_section_start(se->idstr, se->section_id); save_section_header(f, se, QEMU_VM_SECTION_PART); ret = se->ops->save_live_iterate(f, se->opaque); trace_savevm_section_end(se->idstr, se->section_id, ret); save_section_footer(f, se); if (ret < 0) { error_report("failed to save SaveStateEntry with id(name): " "%d(%s): %d", se->section_id, se->idstr, ret); qemu_file_set_error(f, ret); } if (ret <= 0) { /* Do not proceed to the next vmstate before this one reported completion of the current stage. This serializes the migration and reduces the probability that a faster changing state is synchronized over and over again. */ break; } } return ret; } static bool should_send_vmdesc(void) { MachineState *machine = MACHINE(qdev_get_machine()); bool in_postcopy = migration_in_postcopy(); return !machine->suppress_vmdesc && !in_postcopy; } /* * Calls the save_live_complete_postcopy methods * causing the last few pages to be sent immediately and doing any associated * cleanup. * Note postcopy also calls qemu_savevm_state_complete_precopy to complete * all the other devices, but that happens at the point we switch to postcopy. */ void qemu_savevm_state_complete_postcopy(QEMUFile *f) { SaveStateEntry *se; int ret; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->save_live_complete_postcopy) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } trace_savevm_section_start(se->idstr, se->section_id); /* Section type */ qemu_put_byte(f, QEMU_VM_SECTION_END); qemu_put_be32(f, se->section_id); ret = se->ops->save_live_complete_postcopy(f, se->opaque); trace_savevm_section_end(se->idstr, se->section_id, ret); save_section_footer(f, se); if (ret < 0) { qemu_file_set_error(f, ret); return; } } qemu_put_byte(f, QEMU_VM_EOF); qemu_fflush(f); } static int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy) { SaveStateEntry *se; int ret; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || (in_postcopy && se->ops->has_postcopy && se->ops->has_postcopy(se->opaque)) || !se->ops->save_live_complete_precopy) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } trace_savevm_section_start(se->idstr, se->section_id); save_section_header(f, se, QEMU_VM_SECTION_END); ret = se->ops->save_live_complete_precopy(f, se->opaque); trace_savevm_section_end(se->idstr, se->section_id, ret); save_section_footer(f, se); if (ret < 0) { qemu_file_set_error(f, ret); return -1; } } return 0; } int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, bool in_postcopy, bool inactivate_disks) { MigrationState *ms = migrate_get_current(); JSONWriter *vmdesc = ms->vmdesc; int vmdesc_len; SaveStateEntry *se; int ret; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->vmsd && se->vmsd->early_setup) { /* Already saved during qemu_savevm_state_setup(). */ continue; } ret = vmstate_save(f, se, vmdesc); if (ret) { qemu_file_set_error(f, ret); return ret; } } if (inactivate_disks) { /* Inactivate before sending QEMU_VM_EOF so that the * bdrv_activate_all() on the other end won't fail. */ ret = bdrv_inactivate_all(); if (ret) { error_report("%s: bdrv_inactivate_all() failed (%d)", __func__, ret); qemu_file_set_error(f, ret); return ret; } } if (!in_postcopy) { /* Postcopy stream will still be going */ qemu_put_byte(f, QEMU_VM_EOF); } json_writer_end_array(vmdesc); json_writer_end_object(vmdesc); vmdesc_len = strlen(json_writer_get(vmdesc)); if (should_send_vmdesc()) { qemu_put_byte(f, QEMU_VM_VMDESCRIPTION); qemu_put_be32(f, vmdesc_len); qemu_put_buffer(f, (uint8_t *)json_writer_get(vmdesc), vmdesc_len); } /* Free it now to detect any inconsistencies. */ json_writer_free(vmdesc); ms->vmdesc = NULL; return 0; } int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only, bool inactivate_disks) { int ret; Error *local_err = NULL; bool in_postcopy = migration_in_postcopy(); if (precopy_notify(PRECOPY_NOTIFY_COMPLETE, &local_err)) { error_report_err(local_err); } trace_savevm_state_complete_precopy(); cpu_synchronize_all_states(); if (!in_postcopy || iterable_only) { ret = qemu_savevm_state_complete_precopy_iterable(f, in_postcopy); if (ret) { return ret; } } if (iterable_only) { goto flush; } ret = qemu_savevm_state_complete_precopy_non_iterable(f, in_postcopy, inactivate_disks); if (ret) { return ret; } flush: qemu_fflush(f); return 0; } /* Give an estimate of the amount left to be transferred, * the result is split into the amount for units that can and * for units that can't do postcopy. */ void qemu_savevm_state_pending_estimate(uint64_t *must_precopy, uint64_t *can_postcopy) { SaveStateEntry *se; *must_precopy = 0; *can_postcopy = 0; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->state_pending_estimate) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } se->ops->state_pending_estimate(se->opaque, must_precopy, can_postcopy); } } void qemu_savevm_state_pending_exact(uint64_t *must_precopy, uint64_t *can_postcopy) { SaveStateEntry *se; *must_precopy = 0; *can_postcopy = 0; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->state_pending_exact) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } se->ops->state_pending_exact(se->opaque, must_precopy, can_postcopy); } } void qemu_savevm_state_cleanup(void) { SaveStateEntry *se; Error *local_err = NULL; if (precopy_notify(PRECOPY_NOTIFY_CLEANUP, &local_err)) { error_report_err(local_err); } trace_savevm_state_cleanup(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->ops && se->ops->save_cleanup) { se->ops->save_cleanup(se->opaque); } } } static int qemu_savevm_state(QEMUFile *f, Error **errp) { int ret; MigrationState *ms = migrate_get_current(); MigrationStatus status; if (migration_is_running(ms->state)) { error_setg(errp, QERR_MIGRATION_ACTIVE); return -EINVAL; } if (migrate_block()) { error_setg(errp, "Block migration and snapshots are incompatible"); return -EINVAL; } migrate_init(ms); memset(&mig_stats, 0, sizeof(mig_stats)); memset(&compression_counters, 0, sizeof(compression_counters)); reset_vfio_bytes_transferred(); ms->to_dst_file = f; qemu_mutex_unlock_iothread(); qemu_savevm_state_header(f); qemu_savevm_state_setup(f); qemu_mutex_lock_iothread(); while (qemu_file_get_error(f) == 0) { if (qemu_savevm_state_iterate(f, false) > 0) { break; } } ret = qemu_file_get_error(f); if (ret == 0) { qemu_savevm_state_complete_precopy(f, false, false); ret = qemu_file_get_error(f); } qemu_savevm_state_cleanup(); if (ret != 0) { error_setg_errno(errp, -ret, "Error while writing VM state"); } if (ret != 0) { status = MIGRATION_STATUS_FAILED; } else { status = MIGRATION_STATUS_COMPLETED; } migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP, status); /* f is outer parameter, it should not stay in global migration state after * this function finished */ ms->to_dst_file = NULL; return ret; } void qemu_savevm_live_state(QEMUFile *f) { /* save QEMU_VM_SECTION_END section */ qemu_savevm_state_complete_precopy(f, true, false); qemu_put_byte(f, QEMU_VM_EOF); } int qemu_save_device_state(QEMUFile *f) { SaveStateEntry *se; if (!migration_in_colo_state()) { qemu_put_be32(f, QEMU_VM_FILE_MAGIC); qemu_put_be32(f, QEMU_VM_FILE_VERSION); } cpu_synchronize_all_states(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { int ret; if (se->is_ram) { continue; } ret = vmstate_save(f, se, NULL); if (ret) { return ret; } } qemu_put_byte(f, QEMU_VM_EOF); return qemu_file_get_error(f); } static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id) { SaveStateEntry *se; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!strcmp(se->idstr, idstr) && (instance_id == se->instance_id || instance_id == se->alias_id)) return se; /* Migrating from an older version? */ if (strstr(se->idstr, idstr) && se->compat) { if (!strcmp(se->compat->idstr, idstr) && (instance_id == se->compat->instance_id || instance_id == se->alias_id)) return se; } } return NULL; } enum LoadVMExitCodes { /* Allow a command to quit all layers of nested loadvm loops */ LOADVM_QUIT = 1, }; /* ------ incoming postcopy messages ------ */ /* 'advise' arrives before any transfers just to tell us that a postcopy * *might* happen - it might be skipped if precopy transferred everything * quickly. */ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis, uint16_t len) { PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE); uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps; size_t page_size = qemu_target_page_size(); Error *local_err = NULL; trace_loadvm_postcopy_handle_advise(); if (ps != POSTCOPY_INCOMING_NONE) { error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps); return -1; } switch (len) { case 0: if (migrate_postcopy_ram()) { error_report("RAM postcopy is enabled but have 0 byte advise"); return -EINVAL; } return 0; case 8 + 8: if (!migrate_postcopy_ram()) { error_report("RAM postcopy is disabled but have 16 byte advise"); return -EINVAL; } break; default: error_report("CMD_POSTCOPY_ADVISE invalid length (%d)", len); return -EINVAL; } if (!postcopy_ram_supported_by_host(mis, &local_err)) { error_report_err(local_err); postcopy_state_set(POSTCOPY_INCOMING_NONE); return -1; } remote_pagesize_summary = qemu_get_be64(mis->from_src_file); local_pagesize_summary = ram_pagesize_summary(); if (remote_pagesize_summary != local_pagesize_summary) { /* * This detects two potential causes of mismatch: * a) A mismatch in host page sizes * Some combinations of mismatch are probably possible but it gets * a bit more complicated. In particular we need to place whole * host pages on the dest at once, and we need to ensure that we * handle dirtying to make sure we never end up sending part of * a hostpage on it's own. * b) The use of different huge page sizes on source/destination * a more fine grain test is performed during RAM block migration * but this test here causes a nice early clear failure, and * also fails when passed to an older qemu that doesn't * do huge pages. */ error_report("Postcopy needs matching RAM page sizes (s=%" PRIx64 " d=%" PRIx64 ")", remote_pagesize_summary, local_pagesize_summary); return -1; } remote_tps = qemu_get_be64(mis->from_src_file); if (remote_tps != page_size) { /* * Again, some differences could be dealt with, but for now keep it * simple. */ error_report("Postcopy needs matching target page sizes (s=%d d=%zd)", (int)remote_tps, page_size); return -1; } if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, &local_err)) { error_report_err(local_err); return -1; } if (ram_postcopy_incoming_init(mis)) { return -1; } return 0; } /* After postcopy we will be told to throw some pages away since they're * dirty and will have to be demand fetched. Must happen before CPU is * started. * There can be 0..many of these messages, each encoding multiple pages. */ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis, uint16_t len) { int tmp; char ramid[256]; PostcopyState ps = postcopy_state_get(); trace_loadvm_postcopy_ram_handle_discard(); switch (ps) { case POSTCOPY_INCOMING_ADVISE: /* 1st discard */ tmp = postcopy_ram_prepare_discard(mis); if (tmp) { return tmp; } break; case POSTCOPY_INCOMING_DISCARD: /* Expected state */ break; default: error_report("CMD_POSTCOPY_RAM_DISCARD in wrong postcopy state (%d)", ps); return -1; } /* We're expecting a * Version (0) * a RAM ID string (length byte, name, 0 term) * then at least 1 16 byte chunk */ if (len < (1 + 1 + 1 + 1 + 2 * 8)) { error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len); return -1; } tmp = qemu_get_byte(mis->from_src_file); if (tmp != postcopy_ram_discard_version) { error_report("CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp); return -1; } if (!qemu_get_counted_string(mis->from_src_file, ramid)) { error_report("CMD_POSTCOPY_RAM_DISCARD Failed to read RAMBlock ID"); return -1; } tmp = qemu_get_byte(mis->from_src_file); if (tmp != 0) { error_report("CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp); return -1; } len -= 3 + strlen(ramid); if (len % 16) { error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len); return -1; } trace_loadvm_postcopy_ram_handle_discard_header(ramid, len); while (len) { uint64_t start_addr, block_length; start_addr = qemu_get_be64(mis->from_src_file); block_length = qemu_get_be64(mis->from_src_file); len -= 16; int ret = ram_discard_range(ramid, start_addr, block_length); if (ret) { return ret; } } trace_loadvm_postcopy_ram_handle_discard_end(); return 0; } /* * Triggered by a postcopy_listen command; this thread takes over reading * the input stream, leaving the main thread free to carry on loading the rest * of the device state (from RAM). * (TODO:This could do with being in a postcopy file - but there again it's * just another input loop, not that postcopy specific) */ static void *postcopy_ram_listen_thread(void *opaque) { MigrationIncomingState *mis = migration_incoming_get_current(); QEMUFile *f = mis->from_src_file; int load_res; MigrationState *migr = migrate_get_current(); object_ref(OBJECT(migr)); migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_POSTCOPY_ACTIVE); qemu_sem_post(&mis->thread_sync_sem); trace_postcopy_ram_listen_thread_start(); rcu_register_thread(); /* * Because we're a thread and not a coroutine we can't yield * in qemu_file, and thus we must be blocking now. */ qemu_file_set_blocking(f, true); load_res = qemu_loadvm_state_main(f, mis); /* * This is tricky, but, mis->from_src_file can change after it * returns, when postcopy recovery happened. In the future, we may * want a wrapper for the QEMUFile handle. */ f = mis->from_src_file; /* And non-blocking again so we don't block in any cleanup */ qemu_file_set_blocking(f, false); trace_postcopy_ram_listen_thread_exit(); if (load_res < 0) { qemu_file_set_error(f, load_res); dirty_bitmap_mig_cancel_incoming(); if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING && !migrate_postcopy_ram() && migrate_dirty_bitmaps()) { error_report("%s: loadvm failed during postcopy: %d. All states " "are migrated except dirty bitmaps. Some dirty " "bitmaps may be lost, and present migrated dirty " "bitmaps are correctly migrated and valid.", __func__, load_res); load_res = 0; /* prevent further exit() */ } else { error_report("%s: loadvm failed: %d", __func__, load_res); migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, MIGRATION_STATUS_FAILED); } } if (load_res >= 0) { /* * This looks good, but it's possible that the device loading in the * main thread hasn't finished yet, and so we might not be in 'RUN' * state yet; wait for the end of the main thread. */ qemu_event_wait(&mis->main_thread_load_event); } postcopy_ram_incoming_cleanup(mis); if (load_res < 0) { /* * If something went wrong then we have a bad state so exit; * depending how far we got it might be possible at this point * to leave the guest running and fire MCEs for pages that never * arrived as a desperate recovery step. */ rcu_unregister_thread(); exit(EXIT_FAILURE); } migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, MIGRATION_STATUS_COMPLETED); /* * If everything has worked fine, then the main thread has waited * for us to start, and we're the last use of the mis. * (If something broke then qemu will have to exit anyway since it's * got a bad migration state). */ migration_incoming_state_destroy(); qemu_loadvm_state_cleanup(); rcu_unregister_thread(); mis->have_listen_thread = false; postcopy_state_set(POSTCOPY_INCOMING_END); object_unref(OBJECT(migr)); return NULL; } /* After this message we must be able to immediately receive postcopy data */ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) { PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_LISTENING); Error *local_err = NULL; trace_loadvm_postcopy_handle_listen("enter"); if (ps != POSTCOPY_INCOMING_ADVISE && ps != POSTCOPY_INCOMING_DISCARD) { error_report("CMD_POSTCOPY_LISTEN in wrong postcopy state (%d)", ps); return -1; } if (ps == POSTCOPY_INCOMING_ADVISE) { /* * A rare case, we entered listen without having to do any discards, * so do the setup that's normally done at the time of the 1st discard. */ if (migrate_postcopy_ram()) { postcopy_ram_prepare_discard(mis); } } trace_loadvm_postcopy_handle_listen("after discard"); /* * Sensitise RAM - can now generate requests for blocks that don't exist * However, at this point the CPU shouldn't be running, and the IO * shouldn't be doing anything yet so don't actually expect requests */ if (migrate_postcopy_ram()) { if (postcopy_ram_incoming_setup(mis)) { postcopy_ram_incoming_cleanup(mis); return -1; } } trace_loadvm_postcopy_handle_listen("after uffd"); if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, &local_err)) { error_report_err(local_err); return -1; } mis->have_listen_thread = true; postcopy_thread_create(mis, &mis->listen_thread, "postcopy/listen", postcopy_ram_listen_thread, QEMU_THREAD_DETACHED); trace_loadvm_postcopy_handle_listen("return"); return 0; } static void loadvm_postcopy_handle_run_bh(void *opaque) { Error *local_err = NULL; MigrationIncomingState *mis = opaque; trace_loadvm_postcopy_handle_run_bh("enter"); /* TODO we should move all of this lot into postcopy_ram.c or a shared code * in migration.c */ cpu_synchronize_all_post_init(); trace_loadvm_postcopy_handle_run_bh("after cpu sync"); qemu_announce_self(&mis->announce_timer, migrate_announce_params()); trace_loadvm_postcopy_handle_run_bh("after announce"); /* Make sure all file formats throw away their mutable metadata. * If we get an error here, just don't restart the VM yet. */ bdrv_activate_all(&local_err); if (local_err) { error_report_err(local_err); local_err = NULL; autostart = false; } trace_loadvm_postcopy_handle_run_bh("after invalidate cache"); dirty_bitmap_mig_before_vm_start(); if (autostart) { /* Hold onto your hats, starting the CPU */ vm_start(); } else { /* leave it paused and let management decide when to start the CPU */ runstate_set(RUN_STATE_PAUSED); } qemu_bh_delete(mis->bh); trace_loadvm_postcopy_handle_run_bh("return"); } /* After all discards we can start running and asking for pages */ static int loadvm_postcopy_handle_run(MigrationIncomingState *mis) { PostcopyState ps = postcopy_state_get(); trace_loadvm_postcopy_handle_run(); if (ps != POSTCOPY_INCOMING_LISTENING) { error_report("CMD_POSTCOPY_RUN in wrong postcopy state (%d)", ps); return -1; } postcopy_state_set(POSTCOPY_INCOMING_RUNNING); mis->bh = qemu_bh_new(loadvm_postcopy_handle_run_bh, mis); qemu_bh_schedule(mis->bh); /* We need to finish reading the stream from the package * and also stop reading anything more from the stream that loaded the * package (since it's now being read by the listener thread). * LOADVM_QUIT will quit all the layers of nested loadvm loops. */ return LOADVM_QUIT; } /* We must be with page_request_mutex held */ static gboolean postcopy_sync_page_req(gpointer key, gpointer value, gpointer data) { MigrationIncomingState *mis = data; void *host_addr = (void *) key; ram_addr_t rb_offset; RAMBlock *rb; int ret; rb = qemu_ram_block_from_host(host_addr, true, &rb_offset); if (!rb) { /* * This should _never_ happen. However be nice for a migrating VM to * not crash/assert. Post an error (note: intended to not use *_once * because we do want to see all the illegal addresses; and this can * never be triggered by the guest so we're safe) and move on next. */ error_report("%s: illegal host addr %p", __func__, host_addr); /* Try the next entry */ return FALSE; } ret = migrate_send_rp_message_req_pages(mis, rb, rb_offset); if (ret) { /* Please refer to above comment. */ error_report("%s: send rp message failed for addr %p", __func__, host_addr); return FALSE; } trace_postcopy_page_req_sync(host_addr); return FALSE; } static void migrate_send_rp_req_pages_pending(MigrationIncomingState *mis) { WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) { g_tree_foreach(mis->page_requested, postcopy_sync_page_req, mis); } } static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis) { if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) { error_report("%s: illegal resume received", __func__); /* Don't fail the load, only for this. */ return 0; } /* * Reset the last_rb before we resend any page req to source again, since * the source should have it reset already. */ mis->last_rb = NULL; /* * This means source VM is ready to resume the postcopy migration. */ migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_RECOVER, MIGRATION_STATUS_POSTCOPY_ACTIVE); trace_loadvm_postcopy_handle_resume(); /* Tell source that "we are ready" */ migrate_send_rp_resume_ack(mis, MIGRATION_RESUME_ACK_VALUE); /* * After a postcopy recovery, the source should have lost the postcopy * queue, or potentially the requested pages could have been lost during * the network down phase. Let's re-sync with the source VM by re-sending * all the pending pages that we eagerly need, so these threads won't get * blocked too long due to the recovery. * * Without this procedure, the faulted destination VM threads (waiting for * page requests right before the postcopy is interrupted) can keep hanging * until the pages are sent by the source during the background copying of * pages, or another thread faulted on the same address accidentally. */ migrate_send_rp_req_pages_pending(mis); /* * It's time to switch state and release the fault thread to continue * service page faults. Note that this should be explicitly after the * above call to migrate_send_rp_req_pages_pending(). In short: * migrate_send_rp_message_req_pages() is not thread safe, yet. */ qemu_sem_post(&mis->postcopy_pause_sem_fault); if (migrate_postcopy_preempt()) { /* * The preempt channel will be created in async manner, now let's * wait for it and make sure it's created. */ qemu_sem_wait(&mis->postcopy_qemufile_dst_done); assert(mis->postcopy_qemufile_dst); /* Kick the fast ram load thread too */ qemu_sem_post(&mis->postcopy_pause_sem_fast_load); } return 0; } /** * Immediately following this command is a blob of data containing an embedded * chunk of migration stream; read it and load it. * * @mis: Incoming state * @length: Length of packaged data to read * * Returns: Negative values on error * */ static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) { int ret; size_t length; QIOChannelBuffer *bioc; length = qemu_get_be32(mis->from_src_file); trace_loadvm_handle_cmd_packaged(length); if (length > MAX_VM_CMD_PACKAGED_SIZE) { error_report("Unreasonably large packaged state: %zu", length); return -1; } bioc = qio_channel_buffer_new(length); qio_channel_set_name(QIO_CHANNEL(bioc), "migration-loadvm-buffer"); ret = qemu_get_buffer(mis->from_src_file, bioc->data, length); if (ret != length) { object_unref(OBJECT(bioc)); error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%zu", ret, length); return (ret < 0) ? ret : -EAGAIN; } bioc->usage += length; trace_loadvm_handle_cmd_packaged_received(ret); QEMUFile *packf = qemu_file_new_input(QIO_CHANNEL(bioc)); ret = qemu_loadvm_state_main(packf, mis); trace_loadvm_handle_cmd_packaged_main(ret); qemu_fclose(packf); object_unref(OBJECT(bioc)); return ret; } /* * Handle request that source requests for recved_bitmap on * destination. Payload format: * * len (1 byte) + ramblock_name (<255 bytes) */ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis, uint16_t len) { QEMUFile *file = mis->from_src_file; RAMBlock *rb; char block_name[256]; size_t cnt; cnt = qemu_get_counted_string(file, block_name); if (!cnt) { error_report("%s: failed to read block name", __func__); return -EINVAL; } /* Validate before using the data */ if (qemu_file_get_error(file)) { return qemu_file_get_error(file); } if (len != cnt + 1) { error_report("%s: invalid payload length (%d)", __func__, len); return -EINVAL; } rb = qemu_ram_block_by_name(block_name); if (!rb) { error_report("%s: block '%s' not found", __func__, block_name); return -EINVAL; } migrate_send_rp_recv_bitmap(mis, block_name); trace_loadvm_handle_recv_bitmap(block_name); return 0; } static int loadvm_process_enable_colo(MigrationIncomingState *mis) { int ret = migration_incoming_enable_colo(); if (!ret) { ret = colo_init_ram_cache(); if (ret) { migration_incoming_disable_colo(); } } return ret; } /* * Process an incoming 'QEMU_VM_COMMAND' * 0 just a normal return * LOADVM_QUIT All good, but exit the loop * <0 Error */ static int loadvm_process_command(QEMUFile *f) { MigrationIncomingState *mis = migration_incoming_get_current(); uint16_t cmd; uint16_t len; uint32_t tmp32; cmd = qemu_get_be16(f); len = qemu_get_be16(f); /* Check validity before continue processing of cmds */ if (qemu_file_get_error(f)) { return qemu_file_get_error(f); } if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) { error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len); return -EINVAL; } trace_loadvm_process_command(mig_cmd_args[cmd].name, len); if (mig_cmd_args[cmd].len != -1 && mig_cmd_args[cmd].len != len) { error_report("%s received with bad length - expecting %zu, got %d", mig_cmd_args[cmd].name, (size_t)mig_cmd_args[cmd].len, len); return -ERANGE; } switch (cmd) { case MIG_CMD_OPEN_RETURN_PATH: if (mis->to_src_file) { error_report("CMD_OPEN_RETURN_PATH called when RP already open"); /* Not really a problem, so don't give up */ return 0; } mis->to_src_file = qemu_file_get_return_path(f); if (!mis->to_src_file) { error_report("CMD_OPEN_RETURN_PATH failed"); return -1; } /* * Switchover ack is enabled but no device uses it, so send an ACK to * source that it's OK to switchover. Do it here, after return path has * been created. */ if (migrate_switchover_ack() && !mis->switchover_ack_pending_num) { int ret = migrate_send_rp_switchover_ack(mis); if (ret) { error_report( "Could not send switchover ack RP MSG, err %d (%s)", ret, strerror(-ret)); return ret; } } break; case MIG_CMD_PING: tmp32 = qemu_get_be32(f); trace_loadvm_process_command_ping(tmp32); if (!mis->to_src_file) { error_report("CMD_PING (0x%x) received with no return path", tmp32); return -1; } migrate_send_rp_pong(mis, tmp32); break; case MIG_CMD_PACKAGED: return loadvm_handle_cmd_packaged(mis); case MIG_CMD_POSTCOPY_ADVISE: return loadvm_postcopy_handle_advise(mis, len); case MIG_CMD_POSTCOPY_LISTEN: return loadvm_postcopy_handle_listen(mis); case MIG_CMD_POSTCOPY_RUN: return loadvm_postcopy_handle_run(mis); case MIG_CMD_POSTCOPY_RAM_DISCARD: return loadvm_postcopy_ram_handle_discard(mis, len); case MIG_CMD_POSTCOPY_RESUME: return loadvm_postcopy_handle_resume(mis); case MIG_CMD_RECV_BITMAP: return loadvm_handle_recv_bitmap(mis, len); case MIG_CMD_ENABLE_COLO: return loadvm_process_enable_colo(mis); } return 0; } /* * Read a footer off the wire and check that it matches the expected section * * Returns: true if the footer was good * false if there is a problem (and calls error_report to say why) */ static bool check_section_footer(QEMUFile *f, SaveStateEntry *se) { int ret; uint8_t read_mark; uint32_t read_section_id; if (!migrate_get_current()->send_section_footer) { /* No footer to check */ return true; } read_mark = qemu_get_byte(f); ret = qemu_file_get_error(f); if (ret) { error_report("%s: Read section footer failed: %d", __func__, ret); return false; } if (read_mark != QEMU_VM_SECTION_FOOTER) { error_report("Missing section footer for %s", se->idstr); return false; } read_section_id = qemu_get_be32(f); if (read_section_id != se->load_section_id) { error_report("Mismatched section id in footer for %s -" " read 0x%x expected 0x%x", se->idstr, read_section_id, se->load_section_id); return false; } /* All good */ return true; } static int qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis) { uint32_t instance_id, version_id, section_id; SaveStateEntry *se; char idstr[256]; int ret; /* Read section start */ section_id = qemu_get_be32(f); if (!qemu_get_counted_string(f, idstr)) { error_report("Unable to read ID string for section %u", section_id); return -EINVAL; } instance_id = qemu_get_be32(f); version_id = qemu_get_be32(f); ret = qemu_file_get_error(f); if (ret) { error_report("%s: Failed to read instance/version ID: %d", __func__, ret); return ret; } trace_qemu_loadvm_state_section_startfull(section_id, idstr, instance_id, version_id); /* Find savevm section */ se = find_se(idstr, instance_id); if (se == NULL) { error_report("Unknown savevm section or instance '%s' %"PRIu32". " "Make sure that your current VM setup matches your " "saved VM setup, including any hotplugged devices", idstr, instance_id); return -EINVAL; } /* Validate version */ if (version_id > se->version_id) { error_report("savevm: unsupported version %d for '%s' v%d", version_id, idstr, se->version_id); return -EINVAL; } se->load_version_id = version_id; se->load_section_id = section_id; /* Validate if it is a device's state */ if (xen_enabled() && se->is_ram) { error_report("loadvm: %s RAM loading not allowed on Xen", idstr); return -EINVAL; } ret = vmstate_load(f, se); if (ret < 0) { error_report("error while loading state for instance 0x%"PRIx32" of" " device '%s'", instance_id, idstr); return ret; } if (!check_section_footer(f, se)) { return -EINVAL; } return 0; } static int qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis) { uint32_t section_id; SaveStateEntry *se; int ret; section_id = qemu_get_be32(f); ret = qemu_file_get_error(f); if (ret) { error_report("%s: Failed to read section ID: %d", __func__, ret); return ret; } trace_qemu_loadvm_state_section_partend(section_id); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->load_section_id == section_id) { break; } } if (se == NULL) { error_report("Unknown savevm section %d", section_id); return -EINVAL; } ret = vmstate_load(f, se); if (ret < 0) { error_report("error while loading state section id %d(%s)", section_id, se->idstr); return ret; } if (!check_section_footer(f, se)) { return -EINVAL; } return 0; } static int qemu_loadvm_state_header(QEMUFile *f) { unsigned int v; int ret; v = qemu_get_be32(f); if (v != QEMU_VM_FILE_MAGIC) { error_report("Not a migration stream"); return -EINVAL; } v = qemu_get_be32(f); if (v == QEMU_VM_FILE_VERSION_COMPAT) { error_report("SaveVM v2 format is obsolete and don't work anymore"); return -ENOTSUP; } if (v != QEMU_VM_FILE_VERSION) { error_report("Unsupported migration stream version"); return -ENOTSUP; } if (migrate_get_current()->send_configuration) { if (qemu_get_byte(f) != QEMU_VM_CONFIGURATION) { error_report("Configuration section missing"); qemu_loadvm_state_cleanup(); return -EINVAL; } ret = vmstate_load_state(f, &vmstate_configuration, &savevm_state, 0); if (ret) { qemu_loadvm_state_cleanup(); return ret; } } return 0; } static void qemu_loadvm_state_switchover_ack_needed(MigrationIncomingState *mis) { SaveStateEntry *se; QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->switchover_ack_needed) { continue; } if (se->ops->switchover_ack_needed(se->opaque)) { mis->switchover_ack_pending_num++; } } trace_loadvm_state_switchover_ack_needed(mis->switchover_ack_pending_num); } static int qemu_loadvm_state_setup(QEMUFile *f) { SaveStateEntry *se; int ret; trace_loadvm_state_setup(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (!se->ops || !se->ops->load_setup) { continue; } if (se->ops->is_active) { if (!se->ops->is_active(se->opaque)) { continue; } } ret = se->ops->load_setup(f, se->opaque); if (ret < 0) { qemu_file_set_error(f, ret); error_report("Load state of device %s failed", se->idstr); return ret; } } return 0; } void qemu_loadvm_state_cleanup(void) { SaveStateEntry *se; trace_loadvm_state_cleanup(); QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { if (se->ops && se->ops->load_cleanup) { se->ops->load_cleanup(se->opaque); } } } /* Return true if we should continue the migration, or false. */ static bool postcopy_pause_incoming(MigrationIncomingState *mis) { int i; trace_postcopy_pause_incoming(); assert(migrate_postcopy_ram()); /* * Unregister yank with either from/to src would work, since ioc behind it * is the same */ migration_ioc_unregister_yank_from_file(mis->from_src_file); assert(mis->from_src_file); qemu_file_shutdown(mis->from_src_file); qemu_fclose(mis->from_src_file); mis->from_src_file = NULL; assert(mis->to_src_file); qemu_file_shutdown(mis->to_src_file); qemu_mutex_lock(&mis->rp_mutex); qemu_fclose(mis->to_src_file); mis->to_src_file = NULL; qemu_mutex_unlock(&mis->rp_mutex); /* * NOTE: this must happen before reset the PostcopyTmpPages below, * otherwise it's racy to reset those fields when the fast load thread * can be accessing it in parallel. */ if (mis->postcopy_qemufile_dst) { qemu_file_shutdown(mis->postcopy_qemufile_dst); /* Take the mutex to make sure the fast ram load thread halted */ qemu_mutex_lock(&mis->postcopy_prio_thread_mutex); migration_ioc_unregister_yank_from_file(mis->postcopy_qemufile_dst); qemu_fclose(mis->postcopy_qemufile_dst); mis->postcopy_qemufile_dst = NULL; qemu_mutex_unlock(&mis->postcopy_prio_thread_mutex); } migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, MIGRATION_STATUS_POSTCOPY_PAUSED); /* Notify the fault thread for the invalidated file handle */ postcopy_fault_thread_notify(mis); /* * If network is interrupted, any temp page we received will be useless * because we didn't mark them as "received" in receivedmap. After a * proper recovery later (which will sync src dirty bitmap with receivedmap * on dest) these cached small pages will be resent again. */ for (i = 0; i < mis->postcopy_channels; i++) { postcopy_temp_page_reset(&mis->postcopy_tmp_pages[i]); } error_report("Detected IO failure for postcopy. " "Migration paused."); while (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) { qemu_sem_wait(&mis->postcopy_pause_sem_dst); } trace_postcopy_pause_incoming_continued(); return true; } int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis) { uint8_t section_type; int ret = 0; retry: while (true) { section_type = qemu_get_byte(f); ret = qemu_file_get_error_obj_any(f, mis->postcopy_qemufile_dst, NULL); if (ret) { break; } trace_qemu_loadvm_state_section(section_type); switch (section_type) { case QEMU_VM_SECTION_START: case QEMU_VM_SECTION_FULL: ret = qemu_loadvm_section_start_full(f, mis); if (ret < 0) { goto out; } break; case QEMU_VM_SECTION_PART: case QEMU_VM_SECTION_END: ret = qemu_loadvm_section_part_end(f, mis); if (ret < 0) { goto out; } break; case QEMU_VM_COMMAND: ret = loadvm_process_command(f); trace_qemu_loadvm_state_section_command(ret); if ((ret < 0) || (ret == LOADVM_QUIT)) { goto out; } break; case QEMU_VM_EOF: /* This is the end of migration */ goto out; default: error_report("Unknown savevm section type %d", section_type); ret = -EINVAL; goto out; } } out: if (ret < 0) { qemu_file_set_error(f, ret); /* Cancel bitmaps incoming regardless of recovery */ dirty_bitmap_mig_cancel_incoming(); /* * If we are during an active postcopy, then we pause instead * of bail out to at least keep the VM's dirty data. Note * that POSTCOPY_INCOMING_LISTENING stage is still not enough, * during which we're still receiving device states and we * still haven't yet started the VM on destination. * * Only RAM postcopy supports recovery. Still, if RAM postcopy is * enabled, canceled bitmaps postcopy will not affect RAM postcopy * recovering. */ if (postcopy_state_get() == POSTCOPY_INCOMING_RUNNING && migrate_postcopy_ram() && postcopy_pause_incoming(mis)) { /* Reset f to point to the newly created channel */ f = mis->from_src_file; goto retry; } } return ret; } int qemu_loadvm_state(QEMUFile *f) { MigrationIncomingState *mis = migration_incoming_get_current(); Error *local_err = NULL; int ret; if (qemu_savevm_state_blocked(&local_err)) { error_report_err(local_err); return -EINVAL; } ret = qemu_loadvm_state_header(f); if (ret) { return ret; } if (qemu_loadvm_state_setup(f) != 0) { return -EINVAL; } if (migrate_switchover_ack()) { qemu_loadvm_state_switchover_ack_needed(mis); } cpu_synchronize_all_pre_loadvm(); ret = qemu_loadvm_state_main(f, mis); qemu_event_set(&mis->main_thread_load_event); trace_qemu_loadvm_state_post_main(ret); if (mis->have_listen_thread) { /* Listen thread still going, can't clean up yet */ return ret; } if (ret == 0) { ret = qemu_file_get_error(f); } /* * Try to read in the VMDESC section as well, so that dumping tools that * intercept our migration stream have the chance to see it. */ /* We've got to be careful; if we don't read the data and just shut the fd * then the sender can error if we close while it's still sending. * We also mustn't read data that isn't there; some transports (RDMA) * will stall waiting for that data when the source has already closed. */ if (ret == 0 && should_send_vmdesc()) { uint8_t *buf; uint32_t size; uint8_t section_type = qemu_get_byte(f); if (section_type != QEMU_VM_VMDESCRIPTION) { error_report("Expected vmdescription section, but got %d", section_type); /* * It doesn't seem worth failing at this point since * we apparently have an otherwise valid VM state */ } else { buf = g_malloc(0x1000); size = qemu_get_be32(f); while (size > 0) { uint32_t read_chunk = MIN(size, 0x1000); qemu_get_buffer(f, buf, read_chunk); size -= read_chunk; } g_free(buf); } } qemu_loadvm_state_cleanup(); cpu_synchronize_all_post_init(); return ret; } int qemu_load_device_state(QEMUFile *f) { MigrationIncomingState *mis = migration_incoming_get_current(); int ret; /* Load QEMU_VM_SECTION_FULL section */ ret = qemu_loadvm_state_main(f, mis); if (ret < 0) { error_report("Failed to load device state: %d", ret); return ret; } cpu_synchronize_all_post_init(); return 0; } int qemu_loadvm_approve_switchover(void) { MigrationIncomingState *mis = migration_incoming_get_current(); if (!mis->switchover_ack_pending_num) { return -EINVAL; } mis->switchover_ack_pending_num--; trace_loadvm_approve_switchover(mis->switchover_ack_pending_num); if (mis->switchover_ack_pending_num) { return 0; } return migrate_send_rp_switchover_ack(mis); } bool save_snapshot(const char *name, bool overwrite, const char *vmstate, bool has_devices, strList *devices, Error **errp) { BlockDriverState *bs; QEMUSnapshotInfo sn1, *sn = &sn1; int ret = -1, ret2; QEMUFile *f; int saved_vm_running; uint64_t vm_state_size; g_autoptr(GDateTime) now = g_date_time_new_now_local(); AioContext *aio_context; GLOBAL_STATE_CODE(); if (migration_is_blocked(errp)) { return false; } if (!replay_can_snapshot()) { error_setg(errp, "Record/replay does not allow making snapshot " "right now. Try once more later."); return false; } if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { return false; } /* Delete old snapshots of the same name */ if (name) { if (overwrite) { if (bdrv_all_delete_snapshot(name, has_devices, devices, errp) < 0) { return false; } } else { ret2 = bdrv_all_has_snapshot(name, has_devices, devices, errp); if (ret2 < 0) { return false; } if (ret2 == 1) { error_setg(errp, "Snapshot '%s' already exists in one or more devices", name); return false; } } } bs = bdrv_all_find_vmstate_bs(vmstate, has_devices, devices, errp); if (bs == NULL) { return false; } aio_context = bdrv_get_aio_context(bs); saved_vm_running = runstate_is_running(); global_state_store(); vm_stop(RUN_STATE_SAVE_VM); bdrv_drain_all_begin(); aio_context_acquire(aio_context); memset(sn, 0, sizeof(*sn)); /* fill auxiliary fields */ sn->date_sec = g_date_time_to_unix(now); sn->date_nsec = g_date_time_get_microsecond(now) * 1000; sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); if (replay_mode != REPLAY_MODE_NONE) { sn->icount = replay_get_current_icount(); } else { sn->icount = -1ULL; } if (name) { pstrcpy(sn->name, sizeof(sn->name), name); } else { g_autofree char *autoname = g_date_time_format(now, "vm-%Y%m%d%H%M%S"); pstrcpy(sn->name, sizeof(sn->name), autoname); } /* save the VM state */ f = qemu_fopen_bdrv(bs, 1); if (!f) { error_setg(errp, "Could not open VM state file"); goto the_end; } ret = qemu_savevm_state(f, errp); vm_state_size = qemu_file_transferred(f); ret2 = qemu_fclose(f); if (ret < 0) { goto the_end; } if (ret2 < 0) { ret = ret2; goto the_end; } /* The bdrv_all_create_snapshot() call that follows acquires the AioContext * for itself. BDRV_POLL_WHILE() does not support nested locking because * it only releases the lock once. Therefore synchronous I/O will deadlock * unless we release the AioContext before bdrv_all_create_snapshot(). */ aio_context_release(aio_context); aio_context = NULL; ret = bdrv_all_create_snapshot(sn, bs, vm_state_size, has_devices, devices, errp); if (ret < 0) { bdrv_all_delete_snapshot(sn->name, has_devices, devices, NULL); goto the_end; } ret = 0; the_end: if (aio_context) { aio_context_release(aio_context); } bdrv_drain_all_end(); if (saved_vm_running) { vm_start(); } return ret == 0; } void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live, Error **errp) { QEMUFile *f; QIOChannelFile *ioc; int saved_vm_running; int ret; if (!has_live) { /* live default to true so old version of Xen tool stack can have a * successful live migration */ live = true; } saved_vm_running = runstate_is_running(); vm_stop(RUN_STATE_SAVE_VM); global_state_store_running(); ioc = qio_channel_file_new_path(filename, O_WRONLY | O_CREAT | O_TRUNC, 0660, errp); if (!ioc) { goto the_end; } qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-save-state"); f = qemu_file_new_output(QIO_CHANNEL(ioc)); object_unref(OBJECT(ioc)); ret = qemu_save_device_state(f); if (ret < 0 || qemu_fclose(f) < 0) { error_setg(errp, QERR_IO_ERROR); } else { /* libxl calls the QMP command "stop" before calling * "xen-save-devices-state" and in case of migration failure, libxl * would call "cont". * So call bdrv_inactivate_all (release locks) here to let the other * side of the migration take control of the images. */ if (live && !saved_vm_running) { ret = bdrv_inactivate_all(); if (ret) { error_setg(errp, "%s: bdrv_inactivate_all() failed (%d)", __func__, ret); } } } the_end: if (saved_vm_running) { vm_start(); } } void qmp_xen_load_devices_state(const char *filename, Error **errp) { QEMUFile *f; QIOChannelFile *ioc; int ret; /* Guest must be paused before loading the device state; the RAM state * will already have been loaded by xc */ if (runstate_is_running()) { error_setg(errp, "Cannot update device state while vm is running"); return; } vm_stop(RUN_STATE_RESTORE_VM); ioc = qio_channel_file_new_path(filename, O_RDONLY | O_BINARY, 0, errp); if (!ioc) { return; } qio_channel_set_name(QIO_CHANNEL(ioc), "migration-xen-load-state"); f = qemu_file_new_input(QIO_CHANNEL(ioc)); object_unref(OBJECT(ioc)); ret = qemu_loadvm_state(f); qemu_fclose(f); if (ret < 0) { error_setg(errp, QERR_IO_ERROR); } migration_incoming_state_destroy(); } bool load_snapshot(const char *name, const char *vmstate, bool has_devices, strList *devices, Error **errp) { BlockDriverState *bs_vm_state; QEMUSnapshotInfo sn; QEMUFile *f; int ret; AioContext *aio_context; MigrationIncomingState *mis = migration_incoming_get_current(); if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { return false; } ret = bdrv_all_has_snapshot(name, has_devices, devices, errp); if (ret < 0) { return false; } if (ret == 0) { error_setg(errp, "Snapshot '%s' does not exist in one or more devices", name); return false; } bs_vm_state = bdrv_all_find_vmstate_bs(vmstate, has_devices, devices, errp); if (!bs_vm_state) { return false; } aio_context = bdrv_get_aio_context(bs_vm_state); /* Don't even try to load empty VM states */ aio_context_acquire(aio_context); ret = bdrv_snapshot_find(bs_vm_state, &sn, name); aio_context_release(aio_context); if (ret < 0) { return false; } else if (sn.vm_state_size == 0) { error_setg(errp, "This is a disk-only snapshot. Revert to it " " offline using qemu-img"); return false; } /* * Flush the record/replay queue. Now the VM state is going * to change. Therefore we don't need to preserve its consistency */ replay_flush_events(); /* Flush all IO requests so they don't interfere with the new state. */ bdrv_drain_all_begin(); ret = bdrv_all_goto_snapshot(name, has_devices, devices, errp); if (ret < 0) { goto err_drain; } /* restore the VM state */ f = qemu_fopen_bdrv(bs_vm_state, 0); if (!f) { error_setg(errp, "Could not open VM state file"); goto err_drain; } qemu_system_reset(SHUTDOWN_CAUSE_SNAPSHOT_LOAD); mis->from_src_file = f; if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) { ret = -EINVAL; goto err_drain; } aio_context_acquire(aio_context); ret = qemu_loadvm_state(f); migration_incoming_state_destroy(); aio_context_release(aio_context); bdrv_drain_all_end(); if (ret < 0) { error_setg(errp, "Error %d while loading VM state", ret); return false; } return true; err_drain: bdrv_drain_all_end(); return false; } bool delete_snapshot(const char *name, bool has_devices, strList *devices, Error **errp) { if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { return false; } if (bdrv_all_delete_snapshot(name, has_devices, devices, errp) < 0) { return false; } return true; } void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev) { qemu_ram_set_idstr(mr->ram_block, memory_region_name(mr), dev); qemu_ram_set_migratable(mr->ram_block); } void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev) { qemu_ram_unset_idstr(mr->ram_block); qemu_ram_unset_migratable(mr->ram_block); } void vmstate_register_ram_global(MemoryRegion *mr) { vmstate_register_ram(mr, NULL); } bool vmstate_check_only_migratable(const VMStateDescription *vmsd) { /* check needed if --only-migratable is specified */ if (!only_migratable) { return true; } return !(vmsd && vmsd->unmigratable); } typedef struct SnapshotJob { Job common; char *tag; char *vmstate; strList *devices; Coroutine *co; Error **errp; bool ret; } SnapshotJob; static void qmp_snapshot_job_free(SnapshotJob *s) { g_free(s->tag); g_free(s->vmstate); qapi_free_strList(s->devices); } static void snapshot_load_job_bh(void *opaque) { Job *job = opaque; SnapshotJob *s = container_of(job, SnapshotJob, common); int orig_vm_running; job_progress_set_remaining(&s->common, 1); orig_vm_running = runstate_is_running(); vm_stop(RUN_STATE_RESTORE_VM); s->ret = load_snapshot(s->tag, s->vmstate, true, s->devices, s->errp); if (s->ret && orig_vm_running) { vm_start(); } job_progress_update(&s->common, 1); qmp_snapshot_job_free(s); aio_co_wake(s->co); } static void snapshot_save_job_bh(void *opaque) { Job *job = opaque; SnapshotJob *s = container_of(job, SnapshotJob, common); job_progress_set_remaining(&s->common, 1); s->ret = save_snapshot(s->tag, false, s->vmstate, true, s->devices, s->errp); job_progress_update(&s->common, 1); qmp_snapshot_job_free(s); aio_co_wake(s->co); } static void snapshot_delete_job_bh(void *opaque) { Job *job = opaque; SnapshotJob *s = container_of(job, SnapshotJob, common); job_progress_set_remaining(&s->common, 1); s->ret = delete_snapshot(s->tag, true, s->devices, s->errp); job_progress_update(&s->common, 1); qmp_snapshot_job_free(s); aio_co_wake(s->co); } static int coroutine_fn snapshot_save_job_run(Job *job, Error **errp) { SnapshotJob *s = container_of(job, SnapshotJob, common); s->errp = errp; s->co = qemu_coroutine_self(); aio_bh_schedule_oneshot(qemu_get_aio_context(), snapshot_save_job_bh, job); qemu_coroutine_yield(); return s->ret ? 0 : -1; } static int coroutine_fn snapshot_load_job_run(Job *job, Error **errp) { SnapshotJob *s = container_of(job, SnapshotJob, common); s->errp = errp; s->co = qemu_coroutine_self(); aio_bh_schedule_oneshot(qemu_get_aio_context(), snapshot_load_job_bh, job); qemu_coroutine_yield(); return s->ret ? 0 : -1; } static int coroutine_fn snapshot_delete_job_run(Job *job, Error **errp) { SnapshotJob *s = container_of(job, SnapshotJob, common); s->errp = errp; s->co = qemu_coroutine_self(); aio_bh_schedule_oneshot(qemu_get_aio_context(), snapshot_delete_job_bh, job); qemu_coroutine_yield(); return s->ret ? 0 : -1; } static const JobDriver snapshot_load_job_driver = { .instance_size = sizeof(SnapshotJob), .job_type = JOB_TYPE_SNAPSHOT_LOAD, .run = snapshot_load_job_run, }; static const JobDriver snapshot_save_job_driver = { .instance_size = sizeof(SnapshotJob), .job_type = JOB_TYPE_SNAPSHOT_SAVE, .run = snapshot_save_job_run, }; static const JobDriver snapshot_delete_job_driver = { .instance_size = sizeof(SnapshotJob), .job_type = JOB_TYPE_SNAPSHOT_DELETE, .run = snapshot_delete_job_run, }; void qmp_snapshot_save(const char *job_id, const char *tag, const char *vmstate, strList *devices, Error **errp) { SnapshotJob *s; s = job_create(job_id, &snapshot_save_job_driver, NULL, qemu_get_aio_context(), JOB_MANUAL_DISMISS, NULL, NULL, errp); if (!s) { return; } s->tag = g_strdup(tag); s->vmstate = g_strdup(vmstate); s->devices = QAPI_CLONE(strList, devices); job_start(&s->common); } void qmp_snapshot_load(const char *job_id, const char *tag, const char *vmstate, strList *devices, Error **errp) { SnapshotJob *s; s = job_create(job_id, &snapshot_load_job_driver, NULL, qemu_get_aio_context(), JOB_MANUAL_DISMISS, NULL, NULL, errp); if (!s) { return; } s->tag = g_strdup(tag); s->vmstate = g_strdup(vmstate); s->devices = QAPI_CLONE(strList, devices); job_start(&s->common); } void qmp_snapshot_delete(const char *job_id, const char *tag, strList *devices, Error **errp) { SnapshotJob *s; s = job_create(job_id, &snapshot_delete_job_driver, NULL, qemu_get_aio_context(), JOB_MANUAL_DISMISS, NULL, NULL, errp); if (!s) { return; } s->tag = g_strdup(tag); s->devices = QAPI_CLONE(strList, devices); job_start(&s->common); }