x86: Add NULL check to lsl (Jan Kiszka)

According to the Intel specs, lsl performs a check against NULL for the
provided selector, just like lar does. helper_lar() includes the
corresponding code, helper_lsl() was lacking it so far.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6863 c046a42c-6fe2-441c-8c8c-71466251a162

target-i386/op_helper.c

@@ -3241,6 +3241,8 @@ target_ulong helper_lsl(target_ulong selector1)
 
     selector = selector1 & 0xffff;
     eflags = helper_cc_compute_all(CC_OP);
+    if ((selector & 0xfffc) == 0)
+        goto fail;
     if (load_segment(&e1, &e2, selector) != 0)
         goto fail;
     rpl = selector & 3;