linux-kernel - Re: [PATCH] EFI: Only set regions uncacheable if they support it

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Date:	Thu, 15 Mar 2012 07:00:06 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Matthew Garrett <mjg@...hat.com>
CC:	linux-kernel@...r.kernel.org, x86@...nel.org,
	matt.fleming@...el.com
Subject: Re: [PATCH] EFI: Only set regions uncacheable if they support it

On 03/15/2012 06:56 AM, Matthew Garrett wrote:
> The EFI memory region attributes field indicates whether the region can
> be mapped with various cache attributes. Our current implementation always
> marks regions uncacheable if they don't have the writeback support flag.
> This causes us to mark some regions uncacheable even if they don't
> indicate support for being uncacheable, triggering a clflush that may cause
> an MCE. Ensure we only do this for regions which support it.
> 
> Signed-off-by: Matthew Garrett <mjg@...hat.com>

Could you be specific as to what you're seeing in the field?  In
particular, what *do* these memory regions claim to support?

	-hpa

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