On Fri, Jan 8, 2010 at 5:43 PM, Alexander Graf <ag...@suse.de> wrote: > Our guest systems need to know by how much the timebase increases every > second, > so there usually is a "timebase-frequency" property in the cpu leaf of the > device tree. > > This property is missing in OpenBIOS, as is the "clock-frequency" property > that > tells the guest how fast the CPU is. FWIW that one is only used for > /proc/cpuinfo though. > > With qemu, Linux's fallback timebase speed and qemu's internal timebase speed > match up. With KVM, that is no longer true. The guest is running at the same > timebase speed as the host. > > This leads to massive timing problems. On my test machine, a "sleep 2" takes > about 14 seconds with KVM enabled. > > This patch exports the timebase and clock frequencies to OpenBIOS, so it can > then put them into the device tree. I'll push the OpenBIOS change with the > NewWorld patch set, once that's either been reviewed or applied.
IIRC copying the host CPU frequency to guest was rejected earlier for x86.
