linux-kernel - Re: [PATCH]Fix broken VMI in 2.6.27-rc..

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <489B7470.5030408@kernel.org>
Date:	Thu, 07 Aug 2008 15:17:20 -0700
From:	"H. Peter Anvin" <hpa@...nel.org>
To:	Zachary Amsden <zach@...are.com>
CC:	Alok Kataria <akataria@...are.com>,
	"torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	the arch/x86 maintainers <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH]Fix broken VMI in 2.6.27-rc..

Zachary Amsden wrote:
> 
>> Realistically speaking, any (virtual) machine which does *not* have a
>> full complement of lowmem (i.e. less than 896 MB in the common case)
>> will not suffer significatly from losing a few megabytes of address space.
> 
> Yes, the reason to make the fixmap moveable is to allow as much address
> space as possible for big memory (physical) machines.
> 

That being said, the fixmap area being movable more than kind of defeats 
a major point of the fixmap area; the addresses in it are no longer fixed.

The only way I can see around that, though, is to move the 1:1 mapping 
base up by 2/4 MB (for PAE/no PAE, respectively) and put the fixmap area 
there.  Kind of sucks, but would be doable.

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/