From mboxrd@z Thu Jan  1 00:00:00 1970
From: Zachary Amsden <zach@vmware.com>
Subject: Re: hardwired VMI crap
Date: Thu, 08 Mar 2007 14:31:56 -0800
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To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: john stultz <johnstul@us.ibm.com>, LKML <linux-kernel@vger.kernel.org>, Chris Wright <chrisw@sous-sol.org>, Virtualization Mailing List <virtualization@lists.osdl.org>, Ingo Molnar <mingo@elte.hu>, akpm@linux-foundation.org, Linus Torvalds <torvalds@linux-foundation.org>, tglx@linutronix.de
List-Id: virtualization@lists.linuxfoundation.org

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