On 08/06/15 10:46, Andrew Cooper wrote: > On 08/06/15 04:43, Yang Hongyang wrote: >> ioreq page contains evtchn which will be set when we resume the >> secondary vm the first time. The hypervisor will check if the >> evtchn is corrupted, so we cannot zero the ioreq page more >> than one time. >> >> The ioreq->state is always STATE_IOREQ_NONE after the vm is >> suspended, so it is OK if we only zero it one time. >> >> Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com> >> Signed-off-by: Wen congyang <we...@cn.fujitsu.com> >> CC: Andrew Cooper <andrew.coop...@citrix.com> > The issue here is that we are running the restore algorithm over a > domain which has already been running in Xen for a while. This is a > brand new usecase, as far as I am aware. > > Does the qemu process associated with this domain get frozen while the > secondary is being reset, or does the process get destroyed and recreated. > > I have a gut feeling that it would be safer to clear all of the page > other than the event channel, but that depends on exactly what else is > going on. We absolutely don't want to do is have an update to this page > from the primary with an in-progress IOREQ.
Or actually worse, an update from the primary with a different event channel in it. There is no requirement or guarantee that the bufioreq event channels are the same on either side. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
