linux-kernel - Re: [PATCH] x86: trim ram need to check if mtrr is there v3

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Message-ID: <20080125110935.GA20026@elte.hu>
Date:	Fri, 25 Jan 2008 12:09:35 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Yinghai Lu <Yinghai.Lu@....COM>
Cc:	Jeremy Fitzhardinge <jeremy@...p.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: trim ram need to check if mtrr is there v3


* Yinghai Lu <Yinghai.Lu@....COM> wrote:

> [PATCH] x86: trim ram need to check if mtrr is there v3

> > H. Peter Anvin wrote:
> > Looks like the code doesn't check that the CPU *has* MTRRs...
> 
> so more strict check if mtrr is there really.
> bail out if mtrr all blank when qemu cpu model is used
> 
> and check if is AMD as early
> also remove 4G less check, according to hpa.

thanks, applied. Shouldnt we put in an exception for when there is MTRR 
support, but they dont cover anything. Still emit a warning - but 
booting up real slow is still better than losing all of RAM and crashing 
...

i also updated the messages, they now go like this:

  WARNING: strange, CPU MTRRs all blank?

and:

  WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 45MB of RAM.

	Ingo
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