[xen staging] x86: restore semicolon after explicit DS prefix

[patchbot@xxxxxxx]

commit 4dec51ca72c7096b05fcd28640b5be873bd8f2db
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Oct 10 10:54:15 2024 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Oct 10 10:54:15 2024 +0200

    x86: restore semicolon after explicit DS prefix
    
    It's not unnecessary (as the earlier commit claimed): The integrated
    assembler of Clang up to 11 complains about an "invalid operand for
    instruction".
    
    Fixes: b42cf31d1165 ("x86: use alternative_input() in cache_flush()")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/flushtlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/flushtlb.c b/xen/arch/x86/flushtlb.c
index 2a70c5151b..65be0474a8 100644
--- a/xen/arch/x86/flushtlb.c
+++ b/xen/arch/x86/flushtlb.c
@@ -286,7 +286,7 @@ void cache_flush(const void *addr, unsigned int size)
          * + prefix than a clflush + nop, and hence the prefix is added instead
          * of letting the alternative framework fill the gap by appending nops.
          */
-        alternative_input("ds clflush %[p]",
+        alternative_input("ds; clflush %[p]",/* Semicolon for Clang-IAS < 12 */
                           "data16 clflush %[p]", /* clflushopt */
                            X86_FEATURE_CLFLUSHOPT,
                            [p] "m" (*(const char *)(addr)));
--
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