[xen staging] SUPPORT.MD: Correct the amount of physical memory supported for Arm

[patchbot@xxxxxxx]

commit a5968a553f6a6c170254520038f69cb49ff7d191
Author:     Julien Grall <jgrall@xxxxxxxxxx>
AuthorDate: Thu May 5 11:46:57 2022 +0100
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Thu May 5 11:47:09 2022 +0100

    SUPPORT.MD: Correct the amount of physical memory supported for Arm
    
    As part of XSA-385, SUPPORT.MD gained a statement regarding the amount
    of physical memory supported.
    
    However, booting Xen on a Arm platform with that amount of memory would
    result to a breakage because the frametable area is too small.
    
    The wiki [1] (as of April 2022) claims we were able to support up to
    5 TiB on Arm64 and 16 GiB. However, this is not the case because
    the struct page_info has always been bigger than expected (56 bytes
    for 64-bit and 32-bytes for 32-bit).
    
    I don't have any HW with such amount of memory. So rather than
    modifying the code, take the opportunity to use the limit that should
    work on Arm (2 TiB for 64-bit and 12 GiB for 32-bit).
    
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx> #arm part
---
 SUPPORT.md | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/SUPPORT.md b/SUPPORT.md
index 088dda9561..cdf93181cf 100644
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -50,9 +50,10 @@ For the Cortex A57 r0p0 - r1p1, see Errata 832075.
 
 ### Physical Memory
 
-    Status: Supported up to 8 TiB
-
-Hosts with more memory are supported, but not security supported.
+    Status, x86: Supported up to 8 TiB. Hosts with more memory are
+                 supported, but not security supported.
+    Status, Arm32: Supported up to 12 GiB
+    Status, Arm64: Supported up to 2 TiB
 
 ### Physical Memory Hotplug
 
--
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