Re: [PATCH] target/ppc: Fix lxvx/stxvx facility check

[Ilya Leoshkevich <iii@linux.ibm.com>]

On Thu, 2024-09-19 at 13:36 +0200, Claudio Fontana wrote:
> ping, adding Richard.
> 
> We will need to include this downstream because of the breakage its
> lack causes.
> It is already reviewed by me, but some TCG maintainer indicating it
> will be included in some queue would help,
> 
> Thanks,
> 
> Claudio
> 
> On 9/18/24 17:11, Claudio Fontana wrote:
> > Adding Ilya FYI.
> > 
> > Ciao,
> > 
> > Claudio
> > 
> > On 9/11/24 18:19, Claudio Fontana wrote:
> > > On 9/11/24 16:16, Fabiano Rosas wrote:
> > > > The XT check for the lxvx/stxvx instructions is currently
> > > > inverted. This was introduced during the move to decodetree.
> > > > 
> > > > From the ISA:
> > > >   Chapter 7. Vector-Scalar Extension Facility
> > > >   Load VSX Vector Indexed X-form
> > > > 
> > > >   lxvx XT,RA,RB
> > > >   if TX=0 & MSR.VSX=0 then VSX_Unavailable()
> > > >   if TX=1 & MSR.VEC=0 then Vector_Unavailable()
> > > >   ...
> > > >   Let XT be the value 32×TX + T.
> > > > 
> > > > The code currently does the opposite:
> > > > 
> > > >     if (paired || a->rt >= 32) {
> > > >         REQUIRE_VSX(ctx);
> > > >     } else {
> > > >         REQUIRE_VECTOR(ctx);
> > > >     }
> > > > 
> > > > This was already fixed for lxv/stxv at commit "2cc0e449d1
> > > > (target/ppc:
> > > > Fix lxv/stxv MSR facility check)", but the indexed forms were
> > > > missed.
> > > > 
> > > > Cc: qemu-stable@nongnu.org
> > > > Fixes: 70426b5bb7 ("target/ppc: moved stxvx and lxvx from
> > > > legacy to decodtree")
> > > > Signed-off-by: Fabiano Rosas <farosas@suse.de>
> > > > ---
> > > >  target/ppc/translate/vsx-impl.c.inc | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/target/ppc/translate/vsx-impl.c.inc
> > > > b/target/ppc/translate/vsx-impl.c.inc
> > > > index 40a87ddc4a..a869f30e86 100644
> > > > --- a/target/ppc/translate/vsx-impl.c.inc
> > > > +++ b/target/ppc/translate/vsx-impl.c.inc
> > > > @@ -2244,7 +2244,7 @@ static bool do_lstxv_PLS_D(DisasContext
> > > > *ctx, arg_PLS_D *a,
> > > >  
> > > >  static bool do_lstxv_X(DisasContext *ctx, arg_X *a, bool
> > > > store, bool paired)
> > > >  {
> > > > -    if (paired || a->rt >= 32) {
> > > > +    if (paired || a->rt < 32) {
> > > >          REQUIRE_VSX(ctx);
> > > >      } else {
> > > >          REQUIRE_VECTOR(ctx);
> > > 
> > > Reviewed-by: Claudio Fontana <cfontana@suse.de>

FWIW

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>

But I'm not a maintainer, I guess Richard will need to pick it up.