linux-user: init_guest_space: Add a comment about search strategy

Signed-off-by: NLuke Shumaker <lukeshu@parabola.nu>
Message-Id: <20171228180814.9749-10-lukeshu@lukeshu.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

linux-user/elfload.c

@@ -1910,6 +1910,10 @@ unsigned long init_guest_space(unsigned long host_start,
          * happen often.  Probably means we got unlucky and host
          * address space randomization put a shared library somewhere
          * inconvenient.
+         *
+         * This is probably a good strategy if host_start, but is
+         * probably a bad strategy if not, which means we got here
+         * because of trouble with ARM commpage setup.
          */
         munmap((void *)real_start, real_size);
         current_start += qemu_host_page_size;