From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.fraser@eu.citrix.com>
Subject: Re: Illegal PV kernel pfm/pfn translations on PROT_NONE
	ioremaps
Date: Wed, 19 Mar 2008 18:52:13 +0000
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To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, Jan Beulich <jbeulich@novell.com>
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On 19/3/08 17:12, "Stephen C. Tweedie" <sct@redhat.com> wrote:

> On Wed, 2008-03-19 at 16:42 +0000, Keir Fraser wrote:
> 
>>> It might be easier to do this at the pte_machine_to_phys level instead,
>>> where we can potentially take advantage of other bits of the pte to
>>> encode the special casing.
>> 
>> Oh yes, the PAGE_IO type of trick I mentioned in my other email just now.
> 
> Yep.  There are a number of bits that could be used: for example, I
> don't think PROT_WRITE is ever going to be set on a PROT_NONE page,
> either.

My point is the flag would be set even when the protection is not PROT_NONE.
It has other uses beyond fixing this bug.

I might look into doing this myself as I think it is probably the best fix
for this issue.

 -- Keir