From mboxrd@z Thu Jan  1 00:00:00 1970
From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
Subject: Re: [PATCH 0/2] kvm: disable virtualization on kdump
Date: Wed, 29 Oct 2008 07:54:48 -0700
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Cc: Andrew Morton <akpm-3NddpPZAyC0@public.gmane.org>, Eduardo Habkost <ehabkost-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
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	Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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In-Reply-To: <49082FD0.3040009-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> (Avi Kivity's message of "Wed, 29
	Oct 2008 11:41:36 +0200")
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Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> writes:

> Eric W. Biederman wrote:
>>> I think I will get flamed if I try to pull to the core a bunch of code
>>> that always lived in the KVM module.  8)
>>>
>>
>> Why is KVM modular anyway?  That seems like some pretty core cpu
> functionality...
>>
>
> Many reasons.  Developers like the ability to rmmod and modprobe during
> development.  Distros like to keep their non-modular core small.  There is an
> external module distribution that allows users to graft a new kvm on an old
> kernel, which our testers and bleeding edge users like.  Because it's there.

Most of the reason I was wondering is that the cpu hardware probing
largely seems to be a duplicate of what we have in the core for
probing cpu capabilities already, and could likely be made smaller
by building upon the existing codebase.


> svm can writeback into memory at odd times if we don't do this, and the cost is
> small - clear a bit in EFER.  There's no reason to be lazy.

Especially if we can clear that bit unconditionally (when
EFER is present) I'm all for it.

Eric