On Mon, 15 Mar 2010 15:55:26 +0000 "Daniel P. Berrange" <berra...@redhat.com> wrote:
> On Mon, Mar 15, 2010 at 04:01:27PM +0100, Fran?ois Revol wrote: > > Hello, > > while working on a demonstrator for a green-IT project, to show > > scheduled machine shutdown and powering depending on various > > conditions, I wondered if I could use QEMU with wake-on-lan > > transparently, but it seems it's not implemented at all. > > > > I though I could try to add support for it, and with -S it theorically > > should be doable at least for the first boot, but the network packets > > do not go much further until the NIC is actually initialized, as most > > network layers use qemu_can_send_packet() which returns 0 if the > > machine is stopped. > > Hacking this function to return 1 seems to push the packet upward, but > > I couldn't find a single point where I could check for WOL packets, > > different -net subsystems using different code paths. > > > > Also, it seems -no-shutdown doesn't actually "stop the emulation" as > > said in the manual, it actually keeps the vm running (and using cpu), > > despite the OS trying to shutdown via ACPI. At least I tested so with > > Haiku (and acpi=true in kernel config), which properly exits QEMU > > without -no-shutdown. > > Hmm, I think -no-shutdown should at least stop the CPUs executing. It is > not really useful on its own though. The app managing QEMU would want to > use the new JSON based monitor to listen for the SHUTDOWN event to be > emitted, so it can detect the shutdown completing & then take action it > wants either reset the guest, or kill QEMU, etc If I'm not missing something, -no-shutdown calls vm_stop(), which calls pause_all_vcpus().
