[Xen-devel] [PATCH] x86/shim: don't use 32-bit compare on boolean variable

["Jan Beulich" <JBeulich@xxxxxxxx>]

Current upstream gas silently assumes 32-bit operand size for most
operations where the size can't be inferred from an involved register
(my own one doesn't anymore, which is how I've noticed this). It is pure
luck that the 3 bytes following pvh_boot are currently padding ones.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -586,7 +586,7 @@ trampoline_setup:
         push    %eax                /* Magic number. */
         call    reloc
 #ifdef CONFIG_PVH_GUEST
-        cmp     $0, sym_fs(pvh_boot)
+        cmpb    $0, sym_fs(pvh_boot)
         je      1f
         mov     %eax, sym_fs(pvh_start_info_pa)
         jmp     2f




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