File 573d9029-x86emul-suppress-writeback-upon-unsuccessful-MMX-SSE-AVX.patch of Package xen.4507

# Commit 2bb230972c5ddb1ca823f47750b5d46a9d302d0e
# Date 2016-05-19 12:06:33 +0200
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
x86emul: suppress writeback upon unsuccessful MMX/SSE/AVX insn emulation

This in particular prevents updating guest IP when handling the retry
needed to forward the memory access to qemu.

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

--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -3993,6 +3993,8 @@ x86_emulate(
         if ( !rc && (b & 1) && (ea.type == OP_MEM) )
             rc = ops->write(ea.mem.seg, ea.mem.off, mmvalp,
                             ea.bytes, ctxt);
+        if ( rc )
+            goto done;
         dst.type = OP_NONE;
         break;
     }
@@ -4240,6 +4242,8 @@ x86_emulate(
         if ( !rc && (b != 0x6f) && (ea.type == OP_MEM) )
             rc = ops->write(ea.mem.seg, ea.mem.off, mmvalp,
                             ea.bytes, ctxt);
+        if ( rc )
+            goto done;
         dst.type = OP_NONE;
         break;
     }