Add the necessary code to parse the format changes for 'fixed-ram' capability. One of the more notable changes in behavior is that in the 'fixed-ram' case ram pages are restored in one go rather than constantly looping through the migration stream. Also due to idiosyncrasies of the format I have added the 'ram_migrated' since it was easier to simply return directly from ->load_state rather than introducing more conditionals around the code to prevent ->load_state being called multiple times (from qemu_loadvm_section_start_full/qemu_loadvm_section_part_end i.e. from multiple QEMU_VM_SECTION_(PART|END) flags).
Signed-off-by: Nikolay Borisov <nbori...@suse.com> --- migration/migration.h | 2 + migration/ram.c | 95 ++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 95 insertions(+), 2 deletions(-) diff --git a/migration/migration.h b/migration/migration.h index 9aab1b16f407..7a832d072415 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -96,6 +96,8 @@ struct MigrationIncomingState { bool have_listen_thread; QemuThread listen_thread; + bool ram_migrated; + /* For the kernel to send us notifications */ int userfault_fd; /* To notify the fault_thread to wake, e.g., when need to quit */ diff --git a/migration/ram.c b/migration/ram.c index 1dd68c221667..e085a2431f88 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -4330,6 +4330,90 @@ static int parse_ramblocks(QEMUFile *f, ram_addr_t total_ram_bytes) return ret; } + +static int parse_ramblocks_fixed_ram(QEMUFile *f) +{ + int ret = 0; + + while (!ret) { + char id[256]; + RAMBlock *block; + ram_addr_t length; + unsigned long clear_bit_idx; + long num_pages, bitmap_size; + int len = qemu_get_byte(f); + g_autofree unsigned long *dirty_bitmap = NULL; + + qemu_get_buffer(f, (uint8_t *)id, len); + id[len] = 0; + length = qemu_get_be64(f); + + block = qemu_ram_block_by_name(id); + if (block) { + ret = parse_ramblock(f, block, length); + if (ret < 0) { + return ret; + } + } else { + error_report("Unknown ramblock \"%s\", cannot accept " + "migration", id); + ret = -EINVAL; + continue; + } + + /* 1. read the bitmap size */ + num_pages = length >> TARGET_PAGE_BITS; + bitmap_size = qemu_get_be32(f); + + assert(bitmap_size == BITS_TO_LONGS(num_pages)*sizeof(unsigned long)); + + block->pages_offset = qemu_get_be64(f); + + /* 2. read the actual bitmap */ + dirty_bitmap = g_malloc0(bitmap_size); + if (qemu_get_buffer(f, (uint8_t *)dirty_bitmap, bitmap_size) != bitmap_size) { + error_report("Error parsing dirty bitmap"); + return -EINVAL; + } + +#define BUFSIZE (4*1024*1024) + for (unsigned long set_bit_idx = find_first_bit(dirty_bitmap, num_pages); + set_bit_idx < num_pages; + set_bit_idx = find_next_bit(dirty_bitmap, num_pages, clear_bit_idx + 1)) { + + clear_bit_idx = find_next_zero_bit(dirty_bitmap, num_pages, set_bit_idx + 1); + unsigned long len = TARGET_PAGE_SIZE * (clear_bit_idx - set_bit_idx); + ram_addr_t offset = set_bit_idx << TARGET_PAGE_BITS; + + for (size_t read = 0, completed = 0; completed < len; offset += read) { + void *host = host_from_ram_block_offset(block, offset); + size_t read_len = MIN(len, BUFSIZE); + + read = qemu_get_buffer_at(f, host, read_len, + block->pages_offset + offset); + completed += read; + } + } + + /* Skip pages array */ + qemu_set_offset(f, block->pages_offset + length, SEEK_SET); + + /* Check if this is the last ramblock */ + if (qemu_get_be64(f) == RAM_SAVE_FLAG_EOS) { + ret = 1; + } else { + /* + * If not, adjust the internal file index to account for the + * previous 64 bit read + */ + qemu_file_skip(f, -8); + ret = 0; + } + } + + return ret; +} + /** * ram_load_precopy: load pages in precopy case * @@ -4349,7 +4433,7 @@ static int ram_load_precopy(QEMUFile *f) invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE; } - while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) { + while (!ret && !(flags & RAM_SAVE_FLAG_EOS) && !mis->ram_migrated) { ram_addr_t addr; void *host = NULL, *host_bak = NULL; uint8_t ch; @@ -4421,7 +4505,14 @@ static int ram_load_precopy(QEMUFile *f) switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { case RAM_SAVE_FLAG_MEM_SIZE: - ret = parse_ramblocks(f, addr); + if (migrate_fixed_ram()) { + ret = parse_ramblocks_fixed_ram(f); + if (ret == 1) { + mis->ram_migrated = true; + } + } else { + ret = parse_ramblocks(f, addr); + } break; case RAM_SAVE_FLAG_ZERO: -- 2.34.1