Re: [libvirt] [PATCH 0/2 v3 use qemu's dump-guest-meory when vm uses host device

At 04/19/2012 04:38 PM, Daniel P. Berrange Wrote: > On Thu, Apr 19, 2012 at 09:03:16AM +0800, Wen Congyang wrote: >> Currently, we use migrate to dump guest's memory. There is one >> restriction in migrate command: the device's status should be >> stored in qemu because the device's status should be passed to >> target machine. >> >> If we passthrough a host device to guest, the device's status >> is stored in the real device. So migrate command will fail. >> >> We usually use dump when guest is panicked. So there is no need >> to store device's status in the vmcore. >> >> qemu will have a new monitor command dump-guest-memory to dump >> guest memory, but it doesn't support async now(it will support >> later when the common async API is implemented). >> >> So I use dump-guest-memory only when the guest uses host device >> in this patchset. > > Hmm, doesn't the new command generate dump files in a totally > different format to the existing command ? If so I don't > think it is nice behaviour to silently switch between 2 different > dump formats depending on the XML config. I think we'd want some > kind of flag to specify what format is desired. Agree with it. But the new command is not a async command, and it will block the other operation. So I only use it when the vm uses host device(migrate command will fail in this case). The new command will be converted to async command later(after async API is implemented). I think we can allow the user specify the format when the new command is async command.