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From: Andi Kleen <andi@firstfloor.org>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>,
	Nick Piggin <npiggin@suse.de>
Subject: Re: [PATCH] reserve RAM below PHYSICAL_START
Date: Mon, 03 Mar 2008 13:17:46 +0100	[thread overview]
Message-ID: <p73ve446lxx.fsf@bingen.suse.de> (raw)
In-Reply-To: <20080227003325.GS28483@v2.random> (Andrea Arcangeli's message of "Wed\, 27 Feb 2008 01\:33\:25 +0100")

Andrea Arcangeli <andrea@qumranet.com> writes:

> Hello,
>
> this patch allows to prevent linux from using the ram below
> PHYSICAL_START.
>
> The "reserved RAM" can be mapped by virtualization software with to
> create a 1:1 mapping between guest physical (bus) address and host
> physical (bus) address.

Wouldn't it be easier if your virtualization software just marked
that area reserved or unmapped in its e820 map? 

Of if you don't want that you can get the same result with mem=... 
arguments (e.g commonly used by crash dumping) 

Even if that was all not possible for some reason having CONFIG for this would
seem unfortunate for me -- i don't think users really want specially
compiled kernels for specific hypervisors. With paravirt Linux
is trying to get away from that. Some runtime setup method
would be much better.

-Andi

  parent reply	other threads:[~2008-03-03 12:17 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-27  0:33 [PATCH] reserve RAM below PHYSICAL_START Andrea Arcangeli
2008-02-27 23:50 ` Randy Dunlap
2008-02-28 18:36 ` Vivek Goyal
2008-02-29 19:12   ` Andrea Arcangeli
2008-02-29 18:21 ` H. Peter Anvin
2008-02-29 18:50   ` Andrea Arcangeli
2008-03-03 12:17 ` Andi Kleen [this message]
2008-03-10  0:33   ` Andrea Arcangeli

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