Commit 8cb2ca3d authored by Peter Maydell's avatar Peter Maydell
Browse files

target/i386: Generate #UD for LOCK on a register increment 

Fix a TCG crash due to attempting an atomic increment
operation without having set up the address first.
This is a similar case to that dealt with in commit
e84fcd7f, and we fix it in the same way.

Fixes: https://bugs.launchpad.net/qemu/+bug/1807675


Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20190328104750.25046-1-peter.maydell@linaro.org
parent 120cba7f

target/i386/translate.c

+5 −0
Original line number Diff line number Diff line
@@ -1398,6 +1398,11 @@ static void gen_op(DisasContext *s1, int op, TCGMemOp ot, int d) 
static void gen_inc(DisasContext *s1, TCGMemOp ot, int d, int c)

{

    if (s1->prefix & PREFIX_LOCK) {

        if (d != OR_TMP0) {

            /* Lock prefix when destination is not memory */

            gen_illegal_opcode(s1);

            return;

        }

        tcg_gen_movi_tl(s1->T0, c > 0 ? 1 : -1);

        tcg_gen_atomic_add_fetch_tl(s1->T0, s1->A0, s1->T0,

                                    s1->mem_index, ot | MO_LE);