Re: hardwired VMI crap

Zachary Amsden
2007-03-08T22:31:59Z

Jeremy Fitzhardinge wrote:
> Zachary Amsden wrote:
>
>> We faithfully emulate lapic, io_apic, the pit, pic, and a normal
>> interrupt subsystem.
>>
>
> Can you not just use the apic clock driver directly then? Do you need
> to do anything special?
>

The apic clock driver is going to program the apic, not our virtual
clock, which tracks real time, available and stolen time. APIC has no
idea about any of this.

We want an APIC, just purely as a local interrupt controller, and a
separate, paravirt timer device. It is not very complicated.

The problem is that we are not supposed to fiddle with APIC internals,
so we shouldn't be using their clock events, so we can't use their low
level local timer interrupt, and we are not supposed to write our own.
So we need a weird hack somewhere because we are not allowed to use any
of the paths that currently work for our code, because of the
maintenance burden it imposes by misusing the interfaces.

The larger problem I am having is that nobody wants to give productive
feedback on how to fix the problem, just sit around and fling muck.

Zach