tci: Make direct jump patching thread-safe
Ensure direct jump patching in TCI is atomic by:
* naturally aligning a location of direct jump address;
* using atomic_read()/atomic_set() to load/store the address.
Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Message-Id: <1461341333-19646-4-git-send-email-sergey.fedorov@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
diff --git a/tci.c b/tci.c
index 82705fe..a8939e6 100644
--- a/tci.c
+++ b/tci.c
@@ -1089,7 +1089,10 @@
goto exit;
break;
case INDEX_op_goto_tb:
- t0 = tci_read_i32(&tb_ptr);
+ /* Jump address is aligned */
+ tb_ptr = QEMU_ALIGN_PTR_UP(tb_ptr, 4);
+ t0 = atomic_read((int32_t *)tb_ptr);
+ tb_ptr += sizeof(int32_t);
tci_assert(tb_ptr == old_code_ptr + op_size);
tb_ptr += (int32_t)t0;
continue;