x86: drop register reload from INT80 malicious MSI guard

None of the restored registers are actually of interest to the
subsequent code (as opposed to the similar construct on the compat
mode hypercall path).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index e0f5c83ac754392d0b78b924adae89d0fd763c85..dd7f1149d716636e9939836f03976eb20f7c56f6 100644 (file)
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -286,7 +286,6 @@ ENTRY(int80_direct_trap)
 UNLIKELY_START(ne, msi_check)
         movl  $0x80,%edi
         call  check_for_unexpected_msi
-        LOAD_C_CLOBBERED
 UNLIKELY_END(msi_check)
 
         GET_CURRENT(%rbx)