[Qemu-devel] savevm snapshot

[sridhar kulkarni]

I am working on creating a snapshot for ARM based VM running on A7. We don't 
use disk images, so to save the snapshot I am passing "-drive if=none, 
format=qcow2, file=/home/sridhar/qemu_disk_images/dummy.qcow2" as dummy disk to 
save the snapshot.
Then from qemu monitor, I run the "savevm" command. The savevm seems to execute 
and return, however I don't see the RAM being copied correctly, and loadvm 
fails to restore the VM state.
When I debugged, I can see that in "ram_control_save_page", the condition 
highlighted  in bold below fails and function returns RAM_SAVE_CONTROL_NOT_SUPP.
Am I missing something here? From the documents available on qemu.org, I can 
see that savevm should take care of saving RAM contents as well, and it should 
work seamlessly.
Can you help on this?
-Sridhar

| size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset, |
|  |  ram_addr_t offset, size_t size, |
|  |  uint64_t *bytes_sent) |
|  | { |
|  |   if (f->hooks && f->hooks->save_page) { |
|  |  int ret = f->hooks->save_page(f, f->opaque, block_offset, |
|  |  offset, size, bytes_sent); |
|  |  |
|  |  if (ret != RAM_SAVE_CONTROL_DELAYED) { |
|  |  if (bytes_sent && *bytes_sent > 0) { |
|  |  qemu_update_position(f, *bytes_sent); |
|  |  } else if (ret < 0) { |
|  |  qemu_file_set_error(f, ret); |
|  |  } |
|  |  } |
|  |  |
|  |  return ret; |
|  |  } |
|  |  |
|  |  return RAM_SAVE_CONTROL_NOT_SUPP; |
|  | } |