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

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Chen,

On 28/05/15 11:15, Chen Baozi wrote:
> From: Chen Baozi <baozich@xxxxxxxxx>
> 
> 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@xxxxxxxxx>
> ---
>  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.

>  
> -        snprintf(buf, sizeof(buf), "cpu@%u", cpu);
> +        snprintf(buf, sizeof(buf), "cpu@%x", mpidr_aff);

Changing cpu@ is not necessary.

>          res = fdt_begin_node(fdt, buf);
>          if ( res )
>              return res;
> @@ -776,7 +784,7 @@ static int make_cpus_node(const struct domain *d, void 
> *fdt,
>          if ( res )
>              return res;
>  
> -        res = fdt_property_cell(fdt, "reg", cpu);
> +        res = fdt_property_cell(fdt, "reg", mpidr_aff);
>          if ( res )
>              return res;
>  
> 

Regards,


-- 
Julien Grall

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