On 13/01/2015 22:14, Gerhard Wiesinger wrote:
I also had a look at the kernel code again:
http://lxr.free-electrons.com/source/kernel/time/timekeeping.c?v=3.17#L493
499 do {
500 seq = read_seqcount_begin(&tk_core.seq);
501
502 ts->tv_sec = tk->xtime_sec;
503 nsecs = timekeeping_get_ns(&tk->tkr);
504
505 } while (read_seqcount_retry(&tk_core.seq, seq));
So it looks like that the seqcount always changes and therefore loops
forever here (as far as I digged it down this is the only loop here).
Might be something wrong with the memory barriers in recent qemu-kvm
releases?
No, that's not possible. Unless you pause/resume or migrate the VM, all
of the handling of kvmclock is entirely in the kernel.
Paolo