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postcopy: Transmit and compare individual page sizes

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When using postcopy with hugepages, we require the source
and destination page sizes for any RAMBlock to match; note
that different RAMBlocks in the same VM can have different
page sizes.

Transmit them as part of the RAM information header and
fail if there's a difference.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20170224182844.32452-3-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2017-02-24 18:28:30 +00:00
parent e8ca1db29b
commit ef08fb389f
1 changed files with 17 additions and 0 deletions
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17
migration/ram.c
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@ -2027,6 +2027,9 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
qemu_put_byte(f, strlen(block->idstr));
qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
qemu_put_be64(f, block->used_length);
if (migrate_postcopy_ram() && block->page_size != qemu_host_page_size) {
qemu_put_be64(f, block->page_size);
}
}
rcu_read_unlock();
@ -2528,6 +2531,8 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
* be atomic
*/
bool postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING;
/* ADVISE is earlier, it shows the source has the postcopy capability on */
bool postcopy_advised = postcopy_state_get() >= POSTCOPY_INCOMING_ADVISE;
seq_iter++;
@ -2592,6 +2597,18 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
error_report_err(local_err);
}
}
/* For postcopy we need to check hugepage sizes match */
if (postcopy_advised &&
block->page_size != qemu_host_page_size) {
uint64_t remote_page_size = qemu_get_be64(f);
if (remote_page_size != block->page_size) {
error_report("Mismatched RAM page size %s "
"(local) %zd != %" PRId64,
id, block->page_size,
remote_page_size);
ret = -EINVAL;
}
}
ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG,
block->idstr);
} else {