From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Hecht <dhecht@vmware.com>
Subject: Re: + stupid-hack-to-make-mainline-build.patch added to -mm tree
Date: Wed, 07 Mar 2007 13:14:29 -0800
Message-ID: <45EF2B35.9030708@vmware.com>
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Cc: Jeremy Fitzhardinge <jeremy@goop.org>, James Morris <jmorris@namei.org>, Virtualization Mailing List <virtualization@lists.osdl.org>, akpm@linux-foundation.org, john stultz <johnstul@us.ibm.com>, Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
List-Id: virtualization@lists.linuxfoundation.org

On 03/07/2007 01:19 PM, Thomas Gleixner wrote:
> On Wed, 2007-03-07 at 13:02 -0800, Dan Hecht wrote:
>> On 03/07/2007 12:57 PM, Thomas Gleixner wrote:
>>> On Wed, 2007-03-07 at 12:11 -0800, Jeremy Fitzhardinge wrote:
>>>> Dan Hecht wrote:
>>>>> Jeremy, I saw you sent out the Xen version earlier, thanks.  Here's
>>>>> ours for reference (please excuse any formating issues); it's also
>>>>> lean. We'll send out a proper patch later after some more testing:
>>>> So the interrupt side of the clockevent comes through the virtual apic? 
>>>> Where does evt->handle_event get called?
>>>
>>>>         /* We use normal irq0 handler on cpu0. */
>>>>         time_init_hook();
>>> That's exactly the thing I ranted about before. We keep the historic
>>> view of emulated hardware and just wrap it into enough glue code instead
>>> of doing an abstract design, which just gets rid of those hardware
>>> assumptions at all. That's the big advantage of paravirtualization, but
>>> the current way on paravirt ops is just ignoring this.
>>>
>> Are you saying you would prefer we create our own irq handler something 
>> like this rather than using the standard i386 handlers?
>>
>> irqreturn_t vmi_timer_interrupt(int irq, void *dev_id)
>> {
>>     local_event->event_handler(local_event);
>>     return IRQ_HANDLED;
>> }
>>
>> ??  That's fine with me.
> 
> I prefer _ONE_ generic abstract implementation of a clock event, which
> can be used by all hypervisors. Please keep all your wiring and ideas of
> how to best emulate a i386 system away from the kernel as far as you
> can.
> 
> Please sit down with the other hypervisor folks and define the five
> functions you need to interact between clockevents and the particular
> hypervisor and implement it once.
> 
> Then you can change and evolve your idea of how handle them best in your
> hypervisor code, where it belongs.
> 

Okay, I guess we are essentially back to the "XEN & VMI" thread.  Let's 
just keep that discussion in one place.