On 26.01.2017 21:45, Laurent Vivier wrote: > This is a port to ppc of the i386 commit: > 00f4d64 kvmclock: clock should count only if vm is running > > We remove timebase_/pre_save/post_load/ functions, > and use the VM state change handler to save and restore > the guest_timebase (on stop and continue). > > Time base offset has originally been introduced by commit > 98a8b52 spapr: Add support for time base offset migration > > So while VM is paused, the time is stopped. This allows to have > the same result with date (based on Time Base Register) and > hwclock (based on "get-time-of-day" RTAS call). > > Moreover in TCG mode, the Time Base is always paused, so this > patch also adjust the behavior between TCG and KVM. > > VM state field "time_of_the_day_ns" is now useless but we keep > it to be able to migrate to older version of the machine.
Not sure, but the cpu_ppc_clock_vm_state_change() handler is only used with KVM, isn't it? So what happens if you migrate in TCG mode from a new QEMU to an older one? Don't you have to update time_of_the_day_ns here somewhere, too (e.g. in a pre_save handler)? Thomas
