diff options
Diffstat (limited to 'migration/savevm.c')
| -rw-r--r-- | migration/savevm.c | 3303 |
1 files changed, 3303 insertions, 0 deletions
diff --git a/migration/savevm.c b/migration/savevm.c new file mode 100644 index 000000000..d59e976d5 --- /dev/null +++ b/migration/savevm.c @@ -0,0 +1,3303 @@ +/* + * QEMU System Emulator + * + * Copyright (c) 2003-2008 Fabrice Bellard + * Copyright (c) 2009-2015 Red Hat Inc + * + * Authors: + * Juan Quintela <quintela@redhat.com> + * + * 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/vmstate.h" +#include "migration/misc.h" +#include "migration/register.h" +#include "migration/global_state.h" +#include "ram.h" +#include "qemu-file-channel.h" +#include "qemu-file.h" +#include "savevm.h" +#include "postcopy-ram.h" +#include "qapi/error.h" +#include "qapi/qapi-commands-migration.h" +#include "qapi/qmp/json-writer.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/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" + +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 taget 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 ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int iovcnt, + int64_t pos, Error **errp) +{ + int ret; + QEMUIOVector qiov; + + qemu_iovec_init_external(&qiov, iov, iovcnt); + ret = bdrv_writev_vmstate(opaque, &qiov, pos); + if (ret < 0) { + return ret; + } + + return qiov.size; +} + +static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, + size_t size, Error **errp) +{ + return bdrv_load_vmstate(opaque, buf, pos, size); +} + +static int bdrv_fclose(void *opaque, Error **errp) +{ + return bdrv_flush(opaque); +} + +static const QEMUFileOps bdrv_read_ops = { + .get_buffer = block_get_buffer, + .close = bdrv_fclose +}; + +static const QEMUFileOps bdrv_write_ops = { + .writev_buffer = block_writev_buffer, + .close = bdrv_fclose +}; + +static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable) +{ + if (is_writable) { + return qemu_fopen_ops(bs, &bdrv_write_ops, false); + } + return qemu_fopen_ops(bs, &bdrv_read_ops, false); +} + + +/* 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->enabled_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->enabled_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->enabled_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"); + 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; + } + 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); + } + } +} + +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; + } + 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) +{ + int64_t old_offset, size; + + old_offset = qemu_ftell_fast(f); + se->ops->save_state(f, se->opaque); + size = qemu_ftell_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); + } +} + +static int vmstate_save(QEMUFile *f, SaveStateEntry *se, + JSONWriter *vmdesc) +{ + trace_vmstate_save(se->idstr, se->vmsd ? se->vmsd->name : "(old)"); + if (!se->vmsd) { + vmstate_save_old_style(f, se, vmdesc); + return 0; + } + return vmstate_save_state(f, se->vmsd, se->opaque, 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); + } +} + +/** + * 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) +{ + SaveStateEntry *se; + Error *local_err = NULL; + int ret; + + trace_savevm_state_setup(); + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + 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 (qemu_file_rate_limit(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)", + se->section_id, se->idstr); + 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) +{ + g_autoptr(JSONWriter) vmdesc = NULL; + int vmdesc_len; + SaveStateEntry *se; + int ret; + + vmdesc = json_writer_new(false); + json_writer_start_object(vmdesc, NULL); + json_writer_int64(vmdesc, "page_size", qemu_target_page_size()); + json_writer_start_array(vmdesc, "devices"); + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + + if ((!se->ops || !se->ops->save_state) && !se->vmsd) { + continue; + } + if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) { + trace_savevm_section_skip(se->idstr, se->section_id); + continue; + } + + trace_savevm_section_start(se->idstr, se->section_id); + + json_writer_start_object(vmdesc, NULL); + json_writer_str(vmdesc, "name", se->idstr); + json_writer_int64(vmdesc, "instance_id", se->instance_id); + + save_section_header(f, se, QEMU_VM_SECTION_FULL); + ret = vmstate_save(f, se, vmdesc); + if (ret) { + qemu_file_set_error(f, ret); + return ret; + } + trace_savevm_section_end(se->idstr, se->section_id, 0); + save_section_footer(f, se); + + json_writer_end_object(vmdesc); + } + + if (inactivate_disks) { + /* Inactivate before sending QEMU_VM_EOF so that the + * bdrv_invalidate_cache_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); + } + + 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(QEMUFile *f, uint64_t threshold_size, + uint64_t *res_precopy_only, + uint64_t *res_compatible, + uint64_t *res_postcopy_only) +{ + SaveStateEntry *se; + + *res_precopy_only = 0; + *res_compatible = 0; + *res_postcopy_only = 0; + + + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { + if (!se->ops || !se->ops->save_live_pending) { + continue; + } + if (se->ops->is_active) { + if (!se->ops->is_active(se->opaque)) { + continue; + } + } + se->ops->save_live_pending(f, se->opaque, threshold_size, + res_precopy_only, res_compatible, + res_postcopy_only); + } +} + +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_use_block()) { + error_setg(errp, "Block migration and snapshots are incompatible"); + return -EINVAL; + } + + migrate_init(ms); + memset(&ram_counters, 0, sizeof(ram_counters)); + memset(&compression_counters, 0, sizeof(compression_counters)); + 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; + } + if ((!se->ops || !se->ops->save_state) && !se->vmsd) { + continue; + } + if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) { + continue; + } + + save_section_header(f, se, QEMU_VM_SECTION_FULL); + + ret = vmstate_save(f, se, NULL); + if (ret) { + return ret; + } + + save_section_footer(f, se); + } + + 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; + 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)) { + 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 != qemu_target_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, qemu_target_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->listen_thread_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); + trace_loadvm_postcopy_handle_listen(); + Error *local_err = NULL; + + 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); + } + } + + /* + * 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; + } + } + + if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_LISTEN, &local_err)) { + error_report_err(local_err); + return -1; + } + + mis->have_listen_thread = true; + /* Start up the listening thread and wait for it to signal ready */ + qemu_sem_init(&mis->listen_thread_sem, 0); + qemu_thread_create(&mis->listen_thread, "postcopy/listen", + postcopy_ram_listen_thread, NULL, + QEMU_THREAD_DETACHED); + qemu_sem_wait(&mis->listen_thread_sem); + qemu_sem_destroy(&mis->listen_thread_sem); + + return 0; +} + +static void loadvm_postcopy_handle_run_bh(void *opaque) +{ + Error *local_err = NULL; + MigrationIncomingState *mis = opaque; + + /* TODO we should move all of this lot into postcopy_ram.c or a shared code + * in migration.c + */ + cpu_synchronize_all_post_init(); + + qemu_announce_self(&mis->announce_timer, migrate_announce_params()); + + /* Make sure all file formats flush their mutable metadata. + * If we get an error here, just don't restart the VM yet. */ + bdrv_invalidate_cache_all(&local_err); + if (local_err) { + error_report_err(local_err); + local_err = NULL; + autostart = false; + } + + trace_loadvm_postcopy_handle_run_cpu_sync(); + + trace_loadvm_postcopy_handle_run_vmstart(); + + 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); +} + +/* 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); + + 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_fopen_channel_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); + } + + trace_loadvm_process_command(cmd, len); + if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) { + error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len); + return -EINVAL; + } + + 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; + } + 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 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) +{ + trace_postcopy_pause_incoming(); + + assert(migrate_postcopy_ram()); + + /* Clear the triggered bit to allow one recovery */ + mis->postcopy_recover_triggered = false; + + /* + * 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); + + 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); + + 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); + + if (qemu_file_get_error(f)) { + ret = qemu_file_get_error(f); + 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; + } + + 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; +} + +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; + + 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(); + + ret = global_state_store(); + if (ret) { + error_setg(errp, "Error saving global state"); + return false; + } + 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_ftell(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_fopen_channel_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_fopen_channel_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_NONE); + 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); +} |