linux-kernel - Re: iommu: it could use some documentation

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: <20080319151346.GA28798@elte.hu>
Date:	Wed, 19 Mar 2008 16:13:46 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Pavel Machek <pavel@....cz>
Cc:	kernel list <linux-kernel@...r.kernel.org>, andi@...stfloor.org,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: iommu: it could use some documentation

* Pavel Machek <pavel@....cz> wrote:

> Fix coding style in pci-dma_64.c and add stubs for documentation. I 
> hope someone fills the rest, I understand maybe off and soft...

> +	iommu=		[x86]
> +		off
> +		force
> +		noforce
> +		biomerge
> +		panic
> +		nopanic
> +		merge
> +		nomerge
> +		forcesac
> +		soft

these are mostly quirks to get boards booting - few people use these for 
performance tuning. SAC has an address space limit (40 bits) but is 
faster, DAC can cover the physical address range but is slower. The 
softiotlb we better forget about ;-)

if you are interested in fixing this, the descriptions from 
Documentation/x86_64/boot-options.txt should/could be merged into 
Documentation/kernel-parameters.txt.

	Ingo
--
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/