Re: QEMU PIC indirection patch for in-kernel APIC work

Avi Kivity
2007-04-05T06:54:48Z

Anthony Liguori wrote:
>
> Yeah, I think this is a good point. If we're going to push the APIC
> into the kernel, we might as well put the PIT there too. The timing
> stuff is an absolute mess in QEMU since it wants to get a fast high
> res clock but isn't aware of things like CPU migration.

qemu timing could indeed use an overhaul, for example not relying on a
perioding tick but instead calculating the next wakeup event (for which
it has all the infrastructure already; just unused).

> I'm pretty sure that if you are on an SMP host, some bad things can
> happen with the QEMU timer code since it relies on the rdtsc.

It seems to compensate for it.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.