On Thu, Jun 7, 2012 at 4:24 AM, 陳韋任 (Wei-Ren Chen) <che...@iis.sinica.edu.tw> wrote: > On Wed, Jun 06, 2012 at 11:23:37AM +0100, Stefan Hajnoczi wrote: >> On Sun, Jun 3, 2012 at 9:50 PM, Yue Chen <ycyc...@gmail.com> wrote: >> > I'm doing something like a simple and lightweight REPLAY program out of >> > QEMU, only including CPU, MEMORY, and DISK. I'm implementing it with a >> > shadow CPU (register state), shadow memory(from?"pmemsave") and shadow >> > ".img" file (disk). >> >> Why doesn't the "savevm" command provide the snapshotting you need? >> It sounds like you're trying to do VM snapshots yourself. > > Does `savevm` and reply do the same thing? :)
No. 'savevm' and 'loadvm' are purely for saving and restoring a snapshot of the VM disk, RAM, and devices. Replay is something that could be built on top of that snapshotting functionality, and I think it's something along the lines of why savevm/loadvm were added and why qcow2 has internal snapshots (before my time but I think Fabrice was working on something like replay or reversible debugging). But replay is really hard for a system that interacts with the outside world (e.g. internet). Stefan
