lkml.org 
[lkml]   [2023]   [Jun]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RESUBMIT][PATCH] x86/mm: Fix PAT bit missing from page protection modify mask
From
On 02.06.23 16:43, Borislav Petkov wrote:
> On Thu, Jun 01, 2023 at 10:47:39AM +0200, Juergen Gross wrote:
>> As described in the commit message, this only works on bare metal due to the
>> PAT bit not being needed for WC mappings.
>>
>> Making this patch Xen specific would try to cure the symptoms without fixing
>> the underlying problem: _PAGE_PAT should be regarded the same way as the bits
>> for caching mode (_PAGE_CHG_MASK).
>
> So why isn't _PAGE_PAT part of _PAGE_CHG_MASK?

This would result in problems for large pages: _PAGE_PSE is at the same
position as _PAGE_PAT (large pages are using _PAGE_PAT_LARGE instead).

Yes, x86 ABI is a mess.


Juergen

[unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2023-06-02 16:49    [W:0.079 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site