[xen master] x86/entry: Use 32bit XOR in handle_ist_exception

[patchbot@xxxxxxx]

commit 625f2cc66f53c7f1bf56562bf96c06510087d484
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Feb 10 21:22:37 2023 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Nov 21 13:28:51 2023 +0000

    x86/entry: Use 32bit XOR in handle_ist_exception
    
    This is a micro-optimsiation for Silvermont microarchitectures, which don't
    recognise the 64bit form as a zeroing idiom.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/x86_64/entry.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 9a7b129aa7..d95fc75b34 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -1027,7 +1027,7 @@ handle_ist_exception:
          * Interrupted guest context. Clear the restore value for xen_cr3
          * and copy the context to stack bottom.
          */
-        xor   %r15, %r15
+        xor   %r15d, %r15d
         xor   %ebx, %ebx
         GET_CPUINFO_FIELD(guest_cpu_user_regs,di)
         movq  %rsp,%rsi
--
generated by git-patchbot for /home/xen/git/xen.git#master