[Qemu-devel] [PATCH 0/3] balloon: error if guest driver is not initialised

[Amit Shah]

Hello,

These patches make qemu generate an error on failure in setting a
balloon value:

(qemu) balloon 400
Device 'balloon' has not been activated

This can happen when the guest hasn't yet loaded a balloon driver.

Previously, such a ballooning attempt didn't produce an error, but the
virtio-balloon driver remembered the value nevertheless, causing a
module load in the guest using the attempted balloon value
originally.  This may not be the desired course of action.

I've re-used the QERR_DEVICE_NOT_ACTIVE error message, I think it fits
in this case too.  If not, let me know and I'll change it to something
else.

Please review and apply.

Amit Shah (3):
  balloon: Make functions return 0 on OK, -1 on error.
  balloon: report error if ballooning operation fails
  virtio-balloon: report error if balloon driver in guest not available

 balloon.c           |   19 ++++++++++++-------
 balloon.h           |    2 +-
 hw/virtio-balloon.c |    6 +++++-
 3 files changed, 18 insertions(+), 9 deletions(-)

-- 
1.7.7.3