Re: [PATCH V4 6/8] xen/arm: Set 'reg' of cpu node for dom0 to match MPIDR's affinity

[Chen Baozi <cbz@baozis.org>]

On Fri, May 29, 2015 at 04:49:42PM +0100, Julien Grall wrote:
> Hi Chen,
> 
> On 28/05/15 11:15, Chen Baozi wrote:
> > From: Chen Baozi <baozich@gmail.com>
> > 
> > According to ARM CPUs bindings, the reg field should match the MPIDR's
> > affinity bits. We will use AFF0 and AFF1 when constructing the reg value
> > of the guest at the moment, for it is enough for the current max vcpu
> > number.
> > 
> > Signed-off-by: Chen Baozi <baozich@gmail.com>
> > ---
> >  xen/arch/arm/domain_build.c | 14 +++++++++++---
> >  1 file changed, 11 insertions(+), 3 deletions(-)
> > 
> > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> > index a156de9..5591d82 100644
> > --- a/xen/arch/arm/domain_build.c
> > +++ b/xen/arch/arm/domain_build.c
> > @@ -712,6 +712,7 @@ static int make_cpus_node(const struct domain *d, void *fdt,
> >      char buf[15];
> >      u32 clock_frequency;
> >      bool_t clock_valid;
> > +    uint32_t mpidr_aff;
> >  
> >      DPRINT("Create cpus node\n");
> >  
> > @@ -761,9 +762,16 @@ static int make_cpus_node(const struct domain *d, void *fdt,
> >  
> >      for ( cpu = 0; cpu < d->max_vcpus; cpu++ )
> >      {
> > -        DPRINT("Create cpu@%u node\n", cpu);
> > +        /*
> > +         * According to ARM CPUs bindings, the reg field should match
> > +         * the MPIDR's affinity bits. We will use AFF0 and AFF1 when
> > +         * constructing the reg value of the guest at the moment, for it
> > +         * is enough for the current max vcpu number.
> > +         */
> > +        mpidr_aff = vcpuid_to_vaffinity(cpu);
> > +        DPRINT("Create cpu@%x node\n", mpidr_aff);
> 
> I would print both the "logical CPUID" and the MPIDR. It will be easier
> for debugging.

Ok.

> 
> >  
> > -        snprintf(buf, sizeof(buf), "cpu@%u", cpu);
> > +        snprintf(buf, sizeof(buf), "cpu@%x", mpidr_aff);
> 
> Changing cpu@ is not necessary.

See my previous comment about this.

Cheers,

Baozi.