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Re: [Xen-devel] [PATCH v2 13/24] xen/arm: page: Remove unused attributes DEV_NONSHARED and DEV_CACHED


On 20/09/17 00:32, Stefano Stabellini wrote:
On Tue, 12 Sep 2017, Julien Grall wrote:
They were imported from non-LPAE Linux, but Xen is LPAE only. It is time
to do some clean-up in the memory attribute and keep only what make
sense for Xen. Follow-up patch will do more clean-up.

Also, update the comment saying our attribute matches Linux.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>

     Changes in v2:
         - Add Andre's reviewed-by
  xen/include/asm-arm/page.h | 10 +++-------
  1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index b8d641bfaf..d7939bb944 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -21,9 +21,9 @@
  #define LPAE_SH_OUTER         0x2
  #define LPAE_SH_INNER         0x3
-/* LPAE Memory region attributes, to match Linux's (non-LPAE) choices.
- * Indexed by the AttrIndex bits of a LPAE entry;
- * the 8-bit fields are packed little-endian into MAIR0 and MAIR1
+ * LPAE Memory region attributes. Indexed by the AttrIndex bits of a
+ * LPAE entry; the 8-bit fields are packed little-endian into MAIR0 and MAIR1.
   *                 ai    encoding
   *   UNCACHED      000   0000 0000  -- Strongly Ordered
@@ -35,9 +35,7 @@
   *   reserved      110
   *   WRITEALLOC    111   1111 1111  -- Write-back write-allocate
   *   DEV_WC        001   (== BUFFERABLE)
- *   DEV_CACHED    011   (== WRITEBACK)
  #define MAIR0VAL 0xeeaa4400
  #define MAIR1VAL 0xff000004

I am OK with removing unused memory attributes, but please update
MAIR0VAL and MAIR1VAL accordingly.  They still have their old values

As you may have seen below in the patch. They were just aliased to other attributes:


I removed them because they are unused and just wrongly named.

So there are no need to update MAIR0VAL and MAIR1VAL.


Julien Grall

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