target-arm: Log the target EL when taking exceptions

Log the target EL when taking exceptions. This is useful when
debugging guest SW or QEMU itself while transitioning through
the various ELs.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Message-id: 1441311266-8644-2-git-send-email-edgar.iglesias@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target-arm/helper-a64.c

@@ -478,7 +478,8 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
     }
 
     arm_log_exception(cs->exception_index);
-    qemu_log_mask(CPU_LOG_INT, "...from EL%d\n", arm_current_el(env));
+    qemu_log_mask(CPU_LOG_INT, "...from EL%d to EL%d\n", arm_current_el(env),
+                  new_el);
     if (qemu_loglevel_mask(CPU_LOG_INT)
         && !excp_is_internal(cs->exception_index)) {
         qemu_log_mask(CPU_LOG_INT, "...with ESR 0x%" PRIx32 "\n",