Re: [PATCH v4 18/19] hw/arm/smmuv3: Advertise S2FWB

[Mostafa Saleh]

Hi Jean,

On Thu, Jul 04, 2024 at 07:36:58PM +0100, Jean-Philippe Brucker wrote:
> On Mon, Jul 01, 2024 at 11:02:40AM +0000, Mostafa Saleh wrote:
> > QEMU doesn's support memory attributes, so FWB is NOP, this
> > might change in the future if memory attributre would be supported.
> > 
> > Signed-off-by: Mostafa Saleh <smostafa@google.com>
> > ---
> >  hw/arm/smmuv3.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
> > index 807f26f2da..88378e83dd 100644
> > --- a/hw/arm/smmuv3.c
> > +++ b/hw/arm/smmuv3.c
> > @@ -287,6 +287,14 @@ static void smmuv3_init_regs(SMMUv3State *s)
> >      if (FIELD_EX32(s->idr[0], IDR0, S2P)) {
> >          /* XNX is a stage-2-specific feature */
> >          s->idr[3] = FIELD_DP32(s->idr[3], IDR3, XNX, 1);
> > +        if (FIELD_EX32(s->idr[0], IDR0, S1P)) {
> 
> Why is this check needed?
>

I thought that only made sense only for nested SMMUs, but I guess in
practice it’s not important for qemu and Linux doesn’t use it, I can
just drop this patch.

Thanks,
Mostafa

> 
> > +            /*
> > +             * QEMU doesn's support memory attributes, so FWB is NOP, this
> 
> doesn't
> 
> Thanks,
> Jean
> 
> > +             * might change in the future if memory attributre would be
> > +             * supported.
> > +             */
> > +           s->idr[3] = FIELD_DP32(s->idr[3], IDR3, FWB, 1);
> > +        }
> >      }
> >      s->idr[3] = FIELD_DP32(s->idr[3], IDR3, RIL, 1);
> >      s->idr[3] = FIELD_DP32(s->idr[3], IDR3, BBML, 2);
> > -- 
> > 2.45.2.803.g4e1b14247a-goog
> >