linux-kernel - Re: Use of memmap= to forcibly recover memory in 3GB-4GB range

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Message-ID: <CAE9FiQXg29gdrC8RK0Z8vLexju3yNpu9MvJcYHUoPnCNceSWkw@mail.gmail.com>
Date:	Tue, 15 Jan 2013 23:11:57 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Alex Villacís Lasso <a_villacis@...osanto.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Use of memmap= to forcibly recover memory in 3GB-4GB range - is
 this safe?

On Tue, Jan 15, 2013 at 5:47 PM, Alex Villacís Lasso
<a_villacis@...osanto.com> wrote:
> [    0.000000] e820: BIOS-provided physical RAM map:
> [    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009f3ff] usable
> [    0.000000] BIOS-e820: [mem 0x000000000009f400-0x000000000009ffff]
> reserved
> [    0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff]
> reserved
> [    0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cf58ffff] usable
> [    0.000000] BIOS-e820: [mem 0x00000000cf590000-0x00000000cf5e2fff] ACPI
> NVS
> [    0.000000] BIOS-e820: [mem 0x00000000cf5e3000-0x00000000cf5effff] ACPI
> data
> [    0.000000] BIOS-e820: [mem 0x00000000cf5f0000-0x00000000cf5fffff]
> reserved
> [    0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff]
> reserved
> [    0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000ffffffff]
> reserved
> [    0.000000] NX (Execute Disable) protection: active
..
> [    0.000000] original variable MTRRs
> [    0.000000] reg 0, base: 4GB, range: 512MB, type WB
> [    0.000000] reg 1, base: 4608MB, range: 256MB, type WB
> [    0.000000] reg 2, base: 0GB, range: 2GB, type WB
> [    0.000000] reg 3, base: 2GB, range: 1GB, type WB
> [    0.000000] reg 4, base: 3GB, range: 256MB, type WB
> [    0.000000] reg 5, base: 3319MB, range: 1MB, type UC
> [    0.000000] reg 6, base: 3320MB, range: 8MB, type UC
> [    0.000000] reg 7, base: 3318MB, range: 1MB, type UC
> [    0.000000] total RAM covered: 4086M

Can you apply attached debug patch to see if the raw e820 is right from BIOS ?

Yinghai

Download attachment "print_raw_e820.patch" of type "application/octet-stream" (1557 bytes)