Message-ID: <4799400C.1060102@zytor.com>
Date: Thu, 24 Jan 2008 17:49:00 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Jeremy Fitzhardinge <jeremy@goop.org>
CC: Yinghai Lu <Yinghai.Lu@Sun.COM>, Ingo Molnar <mingo@elte.hu>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: x86.git: mtrr trimming removes all memory under kvm
References: <47993F1A.5070408@goop.org>
In-Reply-To: <47993F1A.5070408@goop.org>
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Jeremy Fitzhardinge wrote:
> When booting a current x86.git kernel under kvm, I get this:
> 
> (qemu) Linux version 2.6.24-rc8 (jeremy@ezr) (gcc version 4.1.2 20070925 
> (Red Hat 4.1.2-33)) #1928 SMP PREEMPT Thu Jan 24 17:09:04 PST 2008
> early_ioremap_init()
> BIOS-provided physical RAM map:
> BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
> BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
> BIOS-e820: 00000000000e8000 - 0000000000100000 (reserved)
> BIOS-e820: 0000000000100000 - 000000001fff0000 (usable)
> BIOS-e820: 000000001fff0000 - 0000000020000000 (ACPI data)
> BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved)
> console [earlyser0] enabled
> 0MB HIGHMEM available.
> 511MB LOWMEM available.
> Scan SMP from c0000000 for 1024 bytes.
> Scan SMP from c009fc00 for 1024 bytes.
> Scan SMP from c00f0000 for 65536 bytes.
> Scan SMP from c009fc00 for 1024 bytes.
> ***************
> **** WARNING: likely BIOS bug
> **** MTRRs don't cover all of memory, trimmed 131056 pages
> ***************

Looks like the code doesn't check that the CPU *has* MTRRs...

	-hpa
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