Add the necessary code to parse the format changes for the '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.
Signed-off-by: Nikolay Borisov <nbori...@suse.com>
Signed-off-by: Fabiano Rosas <faro...@suse.de>
---
- added sanity check for pages_offset alignment
- s/parsing/reading
- used Error
- fixed buffer size computation, now allowing an arbitrary limit
- fixed dereference of pointer to packed struct member in endianness
conversion
---
migration/ram.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index 4a0ab8105f..08604222f2 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -106,6 +106,12 @@
*/
#define FIXED_RAM_FILE_OFFSET_ALIGNMENT 0x100000
+/*
+ * When doing fixed-ram migration, this is the amount we read from the
+ * pages region in the migration file at a time.
+ */
+#define FIXED_RAM_LOAD_BUF_SIZE 0x100000
+
XBZRLECacheStats xbzrle_counters;
/* used by the search for pages to send */
@@ -2996,6 +3002,35 @@ static void fixed_ram_insert_header(QEMUFile *file,
RAMBlock *block)
qemu_put_buffer(file, (uint8_t *) header, header_size);
}
+static bool fixed_ram_read_header(QEMUFile *file, FixedRamHeader *header,
+ Error **errp)
+{
+ size_t ret, header_size = sizeof(FixedRamHeader);
+
+ ret = qemu_get_buffer(file, (uint8_t *)header, header_size);
+ if (ret != header_size) {
+ error_setg(errp, "Could not read whole fixed-ram migration header "
+ "(expected %zd, got %zd bytes)", header_size, ret);
+ return false;
+ }
+
+ /* migration stream is big-endian */
+ header->version = be32_to_cpu(header->version);
+
+ if (header->version > FIXED_RAM_HDR_VERSION) {
+ error_setg(errp, "Migration fixed-ram capability version mismatch "
+ "(expected %d, got %d)", FIXED_RAM_HDR_VERSION,
+ header->version);
+ return false;
+ }
+
+ header->page_size = be64_to_cpu(header->page_size);
+ header->bitmap_offset = be64_to_cpu(header->bitmap_offset);
+ header->pages_offset = be64_to_cpu(header->pages_offset);
+
+ return true;
+}
+
/*
* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
* long-running RCU critical section. When rcu-reclaims in the code
@@ -3892,6 +3927,80 @@ void colo_flush_ram_cache(void)
trace_colo_flush_ram_cache_end();
}
+static void read_ramblock_fixed_ram(QEMUFile *f, RAMBlock *block,
+ long num_pages, unsigned long *bitmap)
+{
+ unsigned long set_bit_idx, clear_bit_idx;
+ ram_addr_t offset;
+ void *host;
+ size_t read, unread, size, buf_size = FIXED_RAM_LOAD_BUF_SIZE;
+
+ for (set_bit_idx = find_first_bit(bitmap, num_pages);
+ set_bit_idx < num_pages;
+ set_bit_idx = find_next_bit(bitmap, num_pages, clear_bit_idx + 1)) {
+
+ clear_bit_idx = find_next_zero_bit(bitmap, num_pages, set_bit_idx + 1);
+
+ unread = TARGET_PAGE_SIZE * (clear_bit_idx - set_bit_idx);
+ offset = set_bit_idx << TARGET_PAGE_BITS;
+
+ while (unread > 0) {
+ host = host_from_ram_block_offset(block, offset);
+ size = MIN(unread, buf_size);
+
+ read = qemu_get_buffer_at(f, host, size,
+ block->pages_offset + offset);
+ offset += read;
+ unread -= read;
+ }
+ }
+}
+
+static int parse_ramblock_fixed_ram(QEMUFile *f, RAMBlock *block,
+ ram_addr_t length, Error **errp)
+{
+ g_autofree unsigned long *bitmap = NULL;
+ FixedRamHeader header;
+ size_t bitmap_size;
+ long num_pages;
+
+ if (!fixed_ram_read_header(f, &header, errp)) {
+ return -EINVAL;
+ }
+
+ block->pages_offset = header.pages_offset;
+
+ /*
+ * Check the alignment of the file region that contains pages. We
+ * don't enforce FIXED_RAM_FILE_OFFSET_ALIGNMENT to allow that
+ * value to change in the future. Do only a sanity check with page
+ * size alignment.
+ */
+ if (!QEMU_IS_ALIGNED(block->pages_offset, TARGET_PAGE_SIZE)) {
+ error_setg(errp,
+ "Error reading ramblock %s pages, region has bad alignment",
+ block->idstr);
+ return -EINVAL;
+ }
+
+ num_pages = length / header.page_size;
+ bitmap_size = BITS_TO_LONGS(num_pages) * sizeof(unsigned long);
+
+ bitmap = g_malloc0(bitmap_size);
+ if (qemu_get_buffer_at(f, (uint8_t *)bitmap, bitmap_size,
+ header.bitmap_offset) != bitmap_size) {
+ error_setg(errp, "Error reading dirty bitmap");
+ return -EINVAL;
+ }
+
+ read_ramblock_fixed_ram(f, block, num_pages, bitmap);
+
+ /* Skip pages array */
+ qemu_set_offset(f, block->pages_offset + length, SEEK_SET);
+
+ return 0;
+}
+
static int parse_ramblock(QEMUFile *f, RAMBlock *block, ram_addr_t length)
{
int ret = 0;
@@ -3900,6 +4009,16 @@ static int parse_ramblock(QEMUFile *f, RAMBlock *block,
ram_addr_t length)
assert(block);
+ if (migrate_fixed_ram()) {
+ Error *local_err = NULL;
+
+ ret = parse_ramblock_fixed_ram(f, block, length, &local_err);
+ if (local_err) {
+ error_report_err(local_err);
+ }
+ return ret;
+ }
+
if (!qemu_ram_is_migratable(block)) {
error_report("block %s should not be migrated !", block->idstr);
return -EINVAL;
--
2.35.3
