Re: [Qemu-devel] [PATCH for-2.5] tcg: Increase the highwater reservation

[Peter Maydell]

On 1 December 2015 at 16:19, Richard Henderson <address@hidden> wrote:
> If there are a lot of guest memory ops in the TB, the amount of
> code generated by tcg_out_tb_finalize could be well more than 1k.
> In the short term, increase the reservation larger than any TB
> seen in practice.
>
> Reported-by: Aurelien Jarno <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>
> Reported and discussed with Aurelien on IRC yesterday.  This seems
> to be the easiest fix for the upcoming release.  I will fix this
> properly (by modifying every backend's finalize routines) for 2.6.

What would be the result of our hitting this bug? I ask because
there's a report on qemu-discuss about a qemu-i386-on-ARM-host
bug: http://lists.nongnu.org/archive/html/qemu-discuss/2015-11/msg00042.html
and the debug log (http://www.mediafire.com/download/ge611be9vbebbw7/qemu.log)
suggests we're segfaulting in translation on the TB shortly
after we (successfully) translate a TB whose final 'out' size
is 1100 and which has 64 guest writes in it. So I'm wondering
if that's actually the same bug this is fixing...

thanks
-- PMM