[xen master] docs/arm: Document where Xen should be loaded in memory

[patchbot@xxxxxxx]

commit 5415b2b2118bd78d8a04f276a8312f7f0cb1a466
Author:     Julien Grall <jgrall@xxxxxxxxxx>
AuthorDate: Tue Oct 24 11:28:58 2023 +0100
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Wed Oct 25 11:02:33 2023 +0100

    docs/arm: Document where Xen should be loaded in memory
    
    In commit 9d267c049d92 ("xen/arm64: Rework the memory layout"),
    we decided to require Xen to be loaded below 2 TiB to simplify
    the logic to enable the MMU. The limit was decided based on
    how known platform boot plus some slack.
    
    We had a recent report that this is not sufficient on the AVA
    platform with a old firmware [1]. But the restriction is not
    going to change in Xen 4.18. So document the limit clearly
    in docs/misc/arm/booting.txt.
    
    [1] https://lore.kernel.org/20231013122658.1270506-3-leo.yan@xxxxxxxxxx
    
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
    Release-acked-by: Henry Wang <Henry.Wang@xxxxxxx>
---
 docs/misc/arm/booting.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/docs/misc/arm/booting.txt b/docs/misc/arm/booting.txt
index 02f7bb65ec..547f58a7d9 100644
--- a/docs/misc/arm/booting.txt
+++ b/docs/misc/arm/booting.txt
@@ -21,7 +21,9 @@ The exceptions to this on 32-bit ARM are as follows:
  zImage protocol should still be used and not the stricter "raw
  (non-zImage)" protocol described in arm/Booting.
 
-There are no exception on 64-bit ARM.
+The exceptions to this on 64-bit ARM are as follows:
+
+ Xen binary should be loaded in memory below 2 TiB.
 
 Booting Guests
 --------------
--
generated by git-patchbot for /home/xen/git/xen.git#master