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From: ebiederm@xmission.com (Eric W. Biederman)
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Jeremy Fitzhardinge <jeremy@goop.org>,
       Jeff Garzik <jeff@garzik.org>, Andi Kleen <ak@suse.de>,
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Subject: Re: [patches] [PATCH] [21/22] x86_64: Extend bzImage protocol for relocatable bzImage
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Date: Mon, 30 Apr 2007 09:34:20 -0600
In-Reply-To: <1177909434.30071.216.camel@localhost.localdomain> (Rusty
	Russell's message of "Mon, 30 Apr 2007 15:03:54 +1000")
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Rusty Russell <rusty@rustcorp.com.au> writes:

> On Sun, 2007-04-29 at 21:38 -0700, H. Peter Anvin wrote:
>> Rusty Russell wrote:
>> > 
>> > Dammit, Eric, you spend a lot of time using words like "insane" where
>> > you mean we didn't do everything all at once.
>> > 
>> > It's *not* clear that using %esi is sane, but nothing in the current
>> > code prevents that.
>> 
>> Why not?
>
> (I assume you mean why isn't it clear?)
>
> Because VMI uses the presence of a ROM to indicate it's not native.  KVM
> uses a magic MSR IIRC.
>
> I think it makes sense for lguest to change over, tho.  Patches welcome
> 8)

Reading this it occurs to me what I object to wasn't that clear.

I have no problem with the testing of %cs to see if we are not in ring0.
That part while a little odd is fine, and we will certainly need a test
to skip the protected instructions in head.S

What I object to in particular is having (struct lguest_info?) instead
of using the standard format for kernel parameters pointed to in %esi.

Eric