Re: [Qemu-devel] [PATCH v4 11/43] tcg: define CF_PARALLEL and use it for TB hashing along with CF_COUNT_MASK

["Emilio G. Cota" <cota@braap.org>]

On Sun, Aug 27, 2017 at 18:15:50 -0400, Pranith Kumar wrote:
> Hi Emilio,
> 
> On Fri, Jul 21, 2017 at 1:59 AM, Emilio G. Cota <cota@braap.org> wrote:
> > This will enable us to decouple code translation from the value
> > of parallel_cpus at any given time. It will also help us minimize
> > TB flushes when generating code via EXCP_ATOMIC.
> >
> > Note that the declaration of parallel_cpus is brought to exec-all.h
> > to be able to define there the "curr_cflags" inline.
> >
> > Signed-off-by: Emilio G. Cota <cota@braap.org>
> 
> I was testing a winxp image today and I bisected a infinite loop to
> this commit. The loop happens both with and without mttcg, so I think
> it has got to do with something else.

Can you test the below? It lets me boot ubuntu, otherwise it reliably
chokes on a 'rep movsb' *very* early (doesn't even get to grub).

This discusson on v2 might be relevant (I added CF_COUNT_MASK as a
result of it, but it seems I have to revisit that):
  https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg06456.html

Anyway let me know if this fixes it for you. Thanks for testing!

		Emilio

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 025fae0..8b2f233 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -326,7 +326,7 @@ struct TranslationBlock {
 #define CF_INVALID     0x80000 /* TB is stale. Setters must acquire tb_lock */
 #define CF_PARALLEL    0x100000 /* Generate code for a parallel context */
 /* cflags' mask for hashing/comparison */
-#define CF_HASH_MASK (CF_COUNT_MASK | CF_PARALLEL)
+#define CF_HASH_MASK (CF_PARALLEL)

     /* Per-vCPU dynamic tracing state used to generate this TB */
     uint32_t trace_vcpu_dstate;