diff options
| -rw-r--r-- | migration/migration.c | 68 | ||||
| -rw-r--r-- | migration/migration.h | 2 | ||||
| -rw-r--r-- | migration/ram.c | 144 | ||||
| -rw-r--r-- | migration/ram.h | 3 | ||||
| -rw-r--r-- | migration/savevm.c | 2 | ||||
| -rw-r--r-- | migration/trace-events | 3 |
6 files changed, 221 insertions, 1 deletions
diff --git a/migration/migration.c b/migration/migration.c index ec3bc9a..7c5e20b 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -95,6 +95,7 @@ enum mig_rp_message_type { MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */ MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */ + MIG_RP_MSG_RECV_BITMAP, /* send recved_bitmap back to source */ MIG_RP_MSG_MAX }; @@ -524,6 +525,45 @@ void migrate_send_rp_pong(MigrationIncomingState *mis, migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf); } +void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis, + char *block_name) +{ + char buf[512]; + int len; + int64_t res; + + /* + * First, we send the header part. It contains only the len of + * idstr, and the idstr itself. + */ + len = strlen(block_name); + buf[0] = len; + memcpy(buf + 1, block_name, len); + + if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) { + error_report("%s: MSG_RP_RECV_BITMAP only used for recovery", + __func__); + return; + } + + migrate_send_rp_message(mis, MIG_RP_MSG_RECV_BITMAP, len + 1, buf); + + /* + * Next, we dump the received bitmap to the stream. + * + * TODO: currently we are safe since we are the only one that is + * using the to_src_file handle (fault thread is still paused), + * and it's ok even not taking the mutex. However the best way is + * to take the lock before sending the message header, and release + * the lock after sending the bitmap. + */ + qemu_mutex_lock(&mis->rp_mutex); + res = ramblock_recv_bitmap_send(mis->to_src_file, block_name); + qemu_mutex_unlock(&mis->rp_mutex); + + trace_migrate_send_rp_recv_bitmap(block_name, res); +} + MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp) { MigrationCapabilityStatusList *head = NULL; @@ -1802,6 +1842,7 @@ static struct rp_cmd_args { [MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" }, [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" }, [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" }, + [MIG_RP_MSG_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" }, [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" }, }; @@ -1846,6 +1887,19 @@ static bool postcopy_pause_return_path_thread(MigrationState *s) return true; } +static int migrate_handle_rp_recv_bitmap(MigrationState *s, char *block_name) +{ + RAMBlock *block = qemu_ram_block_by_name(block_name); + + if (!block) { + error_report("%s: invalid block name '%s'", __func__, block_name); + return -EINVAL; + } + + /* Fetch the received bitmap and refresh the dirty bitmap */ + return ram_dirty_bitmap_reload(s, block); +} + /* * Handles messages sent on the return path towards the source VM * @@ -1951,6 +2005,20 @@ retry: migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len); break; + case MIG_RP_MSG_RECV_BITMAP: + if (header_len < 1) { + error_report("%s: missing block name", __func__); + mark_source_rp_bad(ms); + goto out; + } + /* Format: len (1B) + idstr (<255B). This ends the idstr. */ + buf[buf[0] + 1] = '\0'; + if (migrate_handle_rp_recv_bitmap(ms, (char *)(buf + 1))) { + mark_source_rp_bad(ms); + goto out; + } + break; + default: break; } diff --git a/migration/migration.h b/migration/migration.h index 4ea5949..2321ea3 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -260,6 +260,8 @@ void migrate_send_rp_pong(MigrationIncomingState *mis, uint32_t value); int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char* rbname, ram_addr_t start, size_t len); +void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis, + char *block_name); void dirty_bitmap_mig_before_vm_start(void); void init_dirty_bitmap_incoming_migration(void); diff --git a/migration/ram.c b/migration/ram.c index cb14399..5542843 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -190,6 +190,70 @@ void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr, nr); } +#define RAMBLOCK_RECV_BITMAP_ENDING (0x0123456789abcdefULL) + +/* + * Format: bitmap_size (8 bytes) + whole_bitmap (N bytes). + * + * Returns >0 if success with sent bytes, or <0 if error. + */ +int64_t ramblock_recv_bitmap_send(QEMUFile *file, + const char *block_name) +{ + RAMBlock *block = qemu_ram_block_by_name(block_name); + unsigned long *le_bitmap, nbits; + uint64_t size; + + if (!block) { + error_report("%s: invalid block name: %s", __func__, block_name); + return -1; + } + + nbits = block->used_length >> TARGET_PAGE_BITS; + + /* + * Make sure the tmp bitmap buffer is big enough, e.g., on 32bit + * machines we may need 4 more bytes for padding (see below + * comment). So extend it a bit before hand. + */ + le_bitmap = bitmap_new(nbits + BITS_PER_LONG); + + /* + * Always use little endian when sending the bitmap. This is + * required that when source and destination VMs are not using the + * same endianess. (Note: big endian won't work.) + */ + bitmap_to_le(le_bitmap, block->receivedmap, nbits); + + /* Size of the bitmap, in bytes */ + size = nbits / 8; + + /* + * size is always aligned to 8 bytes for 64bit machines, but it + * may not be true for 32bit machines. We need this padding to + * make sure the migration can survive even between 32bit and + * 64bit machines. + */ + size = ROUND_UP(size, 8); + + qemu_put_be64(file, size); + qemu_put_buffer(file, (const uint8_t *)le_bitmap, size); + /* + * Mark as an end, in case the middle part is screwed up due to + * some "misterious" reason. + */ + qemu_put_be64(file, RAMBLOCK_RECV_BITMAP_ENDING); + qemu_fflush(file); + + free(le_bitmap); + + if (qemu_file_get_error(file)) { + return qemu_file_get_error(file); + } + + return size + sizeof(size); +} + /* * An outstanding page request, on the source, having been received * and queued @@ -3300,6 +3364,86 @@ static bool ram_has_postcopy(void *opaque) return migrate_postcopy_ram(); } +/* + * Read the received bitmap, revert it as the initial dirty bitmap. + * This is only used when the postcopy migration is paused but wants + * to resume from a middle point. + */ +int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *block) +{ + int ret = -EINVAL; + QEMUFile *file = s->rp_state.from_dst_file; + unsigned long *le_bitmap, nbits = block->used_length >> TARGET_PAGE_BITS; + uint64_t local_size = nbits / 8; + uint64_t size, end_mark; + + trace_ram_dirty_bitmap_reload_begin(block->idstr); + + if (s->state != MIGRATION_STATUS_POSTCOPY_RECOVER) { + error_report("%s: incorrect state %s", __func__, + MigrationStatus_str(s->state)); + return -EINVAL; + } + + /* + * Note: see comments in ramblock_recv_bitmap_send() on why we + * need the endianess convertion, and the paddings. + */ + local_size = ROUND_UP(local_size, 8); + + /* Add paddings */ + le_bitmap = bitmap_new(nbits + BITS_PER_LONG); + + size = qemu_get_be64(file); + + /* The size of the bitmap should match with our ramblock */ + if (size != local_size) { + error_report("%s: ramblock '%s' bitmap size mismatch " + "(0x%"PRIx64" != 0x%"PRIx64")", __func__, + block->idstr, size, local_size); + ret = -EINVAL; + goto out; + } + + size = qemu_get_buffer(file, (uint8_t *)le_bitmap, local_size); + end_mark = qemu_get_be64(file); + + ret = qemu_file_get_error(file); + if (ret || size != local_size) { + error_report("%s: read bitmap failed for ramblock '%s': %d" + " (size 0x%"PRIx64", got: 0x%"PRIx64")", + __func__, block->idstr, ret, local_size, size); + ret = -EIO; + goto out; + } + + if (end_mark != RAMBLOCK_RECV_BITMAP_ENDING) { + error_report("%s: ramblock '%s' end mark incorrect: 0x%"PRIu64, + __func__, block->idstr, end_mark); + ret = -EINVAL; + goto out; + } + + /* + * Endianess convertion. We are during postcopy (though paused). + * The dirty bitmap won't change. We can directly modify it. + */ + bitmap_from_le(block->bmap, le_bitmap, nbits); + + /* + * What we received is "received bitmap". Revert it as the initial + * dirty bitmap for this ramblock. + */ + bitmap_complement(block->bmap, block->bmap, nbits); + + trace_ram_dirty_bitmap_reload_complete(block->idstr); + + ret = 0; +out: + free(le_bitmap); + return ret; +} + static SaveVMHandlers savevm_ram_handlers = { .save_setup = ram_save_setup, .save_live_iterate = ram_save_iterate, diff --git a/migration/ram.h b/migration/ram.h index 3f4b7da..d386f4d 100644 --- a/migration/ram.h +++ b/migration/ram.h @@ -66,5 +66,8 @@ int ramblock_recv_bitmap_test(RAMBlock *rb, void *host_addr); bool ramblock_recv_bitmap_test_byte_offset(RAMBlock *rb, uint64_t byte_offset); void ramblock_recv_bitmap_set(RAMBlock *rb, void *host_addr); void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr, size_t nr); +int64_t ramblock_recv_bitmap_send(QEMUFile *file, + const char *block_name); +int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *rb); #endif diff --git a/migration/savevm.c b/migration/savevm.c index 9f4a95d..7176b35 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1852,7 +1852,7 @@ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis, return -EINVAL; } - /* TODO: send the bitmap back to source */ + migrate_send_rp_recv_bitmap(mis, block_name); trace_loadvm_handle_recv_bitmap(block_name); diff --git a/migration/trace-events b/migration/trace-events index 5bee6d5..72e5708 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -79,6 +79,8 @@ ram_load_postcopy_loop(uint64_t addr, int flags) "@%" PRIx64 " %x" ram_postcopy_send_discard_bitmap(void) "" ram_save_page(const char *rbname, uint64_t offset, void *host) "%s: offset: 0x%" PRIx64 " host: %p" ram_save_queue_pages(const char *rbname, size_t start, size_t len) "%s: start: 0x%zx len: 0x%zx" +ram_dirty_bitmap_reload_begin(char *str) "%s" +ram_dirty_bitmap_reload_complete(char *str) "%s" # migration/migration.c await_return_path_close_on_source_close(void) "" @@ -90,6 +92,7 @@ migrate_fd_cancel(void) "" migrate_handle_rp_req_pages(const char *rbname, size_t start, size_t len) "in %s at 0x%zx len 0x%zx" migrate_pending(uint64_t size, uint64_t max, uint64_t pre, uint64_t compat, uint64_t post) "pending size %" PRIu64 " max %" PRIu64 " (pre = %" PRIu64 " compat=%" PRIu64 " post=%" PRIu64 ")" migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d" +migrate_send_rp_recv_bitmap(char *name, int64_t size) "block '%s' size 0x%"PRIi64 migration_completion_file_err(void) "" migration_completion_postcopy_end(void) "" migration_completion_postcopy_end_after_complete(void) "" |