On 2018-11-27 13:43, Christian Borntraeger wrote: > On 27.11.2018 12:41, David Hildenbrand wrote: >> Just like on other architectures, we should stop the clock while the guest >> is not running. This is already properly done for TCG. Right now, doing an >> offline migration (stop, migrate, cont) can easily trigger stalls in the >> guest. >> >> Even doing a >> (hmp) stop >> ... wait 2 minutes ... >> (hmp) cont >> will already trigger stalls. >> >> So whenever the guest stops, backup the KVM TOD. When continuning to run >> the guest, restore the KVM TOD. > > We do a similar thing for managedsave so it probably makes sense to solve > the stall warnings. Now: At the same time, we actually want to have the guest > see the real time and maybe even share the TOD clock with the host in some > way, while at the same time avoid the stall warnings.
Hmm, by the way, do we also have to consider the "-rtc clock=host|rt|vm" option from the commandl line, or is this an orthogonal concept? Thomas
