x86emul: suppress general register update upon AVX gather failures

While destination and mask registers may indeed need updating in this
case, the rIP update in particular needs to be avoided, as well as e.g.
raising a single step trap.

Reported-by: George Dunlap <george.dunlap@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c
index ea02d100dd670102b0147edd2b327b2f87c24e93..0293a7229239fb753347095940719a6eda74b3c7 100644 (file)
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -8547,6 +8547,9 @@ x86_emulate(
         invoke_stub("", "", "+m" (mask) : "a" (&mask));
         put_stub(stub);
 
+        if ( rc != X86EMUL_OKAY )
+            goto done;
+
         state->simd_size = simd_none;
         break;
     }