On Sat, May 4, 2024 at 7:31 PM Peter Maydell <peter.mayd...@linaro.org> wrote:
>
> On Fri, 3 May 2024 at 19:14, Dorjoy Chowdhury <dorjoychy...@gmail.com> wrote:
> >
> > On Fri, May 3, 2024 at 10:28 PM Peter Maydell <peter.mayd...@linaro.org>
> > wrote:
> > > In the meantime, there is one tiny bit of this that we can
> > > do now:
> > >
> > > > diff --git a/hw/arm/npcm7xx.c b/hw/arm/npcm7xx.c
> > > > index cc68b5d8f1..9d5dcf1a3f 100644
> > > > --- a/hw/arm/npcm7xx.c
> > > > +++ b/hw/arm/npcm7xx.c
> > > > @@ -487,7 +487,7 @@ static void npcm7xx_realize(DeviceState *dev, Error
> > > > **errp)
> > > > /* CPUs */
> > > > for (i = 0; i < nc->num_cpus; i++) {
> > > > object_property_set_int(OBJECT(&s->cpu[i]), "mp-affinity",
> > > > - arm_build_mp_affinity(i,
> > > > NPCM7XX_MAX_NUM_CPUS),
> > > > +
> > > > arm_build_mp_affinity(ARM_CPU(&s->cpu[i]), i, NPCM7XX_MAX_NUM_CPUS),
> > > > &error_abort);
> > > > object_property_set_int(OBJECT(&s->cpu[i]), "reset-cbar",
> > > > NPCM7XX_GIC_CPU_IF_ADDR, &error_abort);
> > >
> > > In this file, the value of the mp-affinity property that the
> > > board is setting is always the same as the default value it
> > > would have anyway. So we can delete the call to
> > > object_property_set_int() entirely, which gives us one fewer
> > > place we need to deal with when we do eventually figure out
> > > how the MPIDR values should work.
> > >
> >
> > Before I send the patch removing the "object_property_set_int" line
> > for "mp-affinity", just so that I understand, where else is it that
> > for npcm7xx the mp_affinity is being set? I can't follow the code
> > easily and I am not seeing where else it is being set to the same
> > value. It's a bit hard to follow the initialization codes in QEMU.
>
> The value that npcm7xx sets here is identical to the default value
> that the Arm CPU will use if we don't set the property at all.
> If the board doesn't set the property then the cpu mp_affinity field
> is left at its default of ARM64_AFFINITY_INVALID, which then causes
> arm_cpu_realizefn() to set it to the result of
> arm_build_mp_affinity(cs->cpu_index, ARM_DEFAULT_CPUS_PER_CLUSTER)
> Although ARM_DEFAULT_CPUS_PER_CLUSTER and NPCM7XX_MAX_NUM_CPUS are
> different, the number of CPUs on an npcm7xx is always exactly 2,
> so we never get to a CPU number high enough for that difference
> to cause the mp_affinity value to be different from the default.
> (The two CPUs get an mp_affinity of 0 and 1.)
>
Understood. Thanks! I sent a patch.
Regards,
Dorjoy
