linux-kernel - Re: [PATCH 3/4] EFI: Add support for variables longer than 1024 bytes

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Date:	Thu, 15 Dec 2011 15:43:56 +0000
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	Mike Waychison <mikew@...gle.com>
Cc:	linux-kernel@...r.kernel.org, x86@...nel.org, hpa@...or.com
Subject: Re: [PATCH 3/4] EFI: Add support for variables longer than 1024
 bytes

On Wed, Dec 14, 2011 at 02:57:51PM -0800, Mike Waychison wrote:
> On Wed, Dec 14, 2011 at 2:39 PM, Matthew Garrett <mjg59@...f.ucam.org> wrote:
> > Hm. I think that'd only work if we expose a new interface. Writes would
> > be easy enough to handle, but reads still need to work for old apps.
> 
> Well,l we could *not* support returning all the data field for
> datasize > 1024, and simply truncate the field.  We are limited by
> PAGE_SIZE by sysfs here anyway (so we don't really want to have a
> variable size memcpy in efivar_show_raw).

We'll pretty much definitely want to be able to read values > 1024 once 
people start shoving keys in there. The PAGE_SIZE limit is one that I'd 
forgotten about, though.

-- 
Matthew Garrett | mjg59@...f.ucam.org
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