Re: [libvirt] [PATCH RFC 0/4] Allow hibernation on guests

As we've added guest agent recently, the whole world of new functionality has opened. As this patch set, which allows domains to enter S4 state. What is needed for this? Patched qemu. As this is not in qemu git, but patches are await to be pushed in very short future. They can be found here: http://lists.gnu.org/archive/html/qemu-devel/2012-01/msg03261.html Despite that, if anybody is willing to give me review if I am going the right way, I'd appreciate it. One thing, that you'll probably notice is this 'set-support-level' command. Basically, it tells GA what qemu version is it running on. Ideally, this should be done as soon as GA starts up. However, that cannot be determined from outside world as GA doesn't emit any events yet. Ideally^2 this command should be left out as it should be qemu who tells its own agent this kind of information. Anyway, I was going to call this command in qemuProcess{Startup, Reconnect,Attach}, but it won't work. We need to un-pause guest CPUs so guest can boot and start GA, but that implies returning from qemuProcess*. So I am setting this just before 'guest-suspend' command, as there is one more thing about GA. It is unable to remember anything upon its restart (GA process). Which has BTW show flaw in our current code with FS freeze & thaw. If we freeze guest FS, and somebody restart GA, the simple FS Thaw will not succeed as GA thinks FS are not frozen. But that's a different cup of tea. Because of what written above, we need to call set-level on every suspend.