[PATCH v3 00/18] libxl: domain save/restore: run in a separate process

[Ian Jackson <ian.jackson@eu.citrix.com>]

This is v3 of my series to asyncify save/restore, rebased to current
tip, retested, and with all comments addressed.

In the list below "A" indicates a patch which has been acked
sufficiently to go in (assuming its dependencies were to go in too).
"*" indicates a new patch in v3.

Preparatory work:

   01/19 libxc: xc_domain_restore, make toolstack_restore const-correct
   02/19 libxl: domain save: rename variables etc.
   03/19 libxl: domain restore: reshuffle, preparing for ao
   04/19 libxl: domain save: API changes for asynchrony

The meat:

   05/19 libxl: domain save/restore: run in a separate process

Some fixups:

 A 06/19 libxl: rename libxl_dom:save_helper to physmap_path
   07/19 libxl: provide libxl__xs_*_checked and libxl__xs_transaction_*
   08/19 libxl: wait for qemu to acknowledge logdirty command

Asyncify writing of qemu save file, too:

   09/19 libxl: datacopier: provide "prefix data" facility
   10/19 libxl: prepare for asynchronous writing of qemu save file
   11/19 libxl: Make libxl__domain_save_device_model asynchronous

Fix gc_opt handling:

 * 12/19 libxl: Add a gc to libxl_get_cpu_topology
 * 13/19 libxl: Do not pass NULL as gc_opt; introduce NOGC
 * 14/19 libxl: Get compiler to warn about gc_opt==NULL

Work on essentially-unrelated bugs:

 A 15/19 xl: Handle return value from libxl_domain_suspend correctly
 A 16/19 libxl: do not leak dms->saved_state
   17/19 libxl: do not leak spawned middle children
 A 18/19 libxl: do not leak an event struct on ignored ao progress
 * 19/19 libxl: DO NOT APPLY enforce prohibition on internal

Thanks,
Ian.