Re: [Xen-devel] [PATCH v4 08/16] libxl/arm: Factor MPIDR computing codes out as a helper

[Julien Grall <julien.grall@xxxxxxx>]

Hi Shannon,

On 16/08/2016 06:25, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>
> Factor MPIDR computing codes out as a helper, so it could be shared
> between DT and ACPI.
>
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>

Regards,

> ---
>  tools/libxl/libxl_arm.c |  8 +-------
>  tools/libxl/libxl_arm.h | 11 +++++++++++
>  2 files changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
> index 8c7fc09..fa0497c 100644
> --- a/tools/libxl/libxl_arm.c
> +++ b/tools/libxl/libxl_arm.c
> @@ -309,13 +309,7 @@ static int make_cpus_node(libxl__gc *gc, void *fdt, int 
> nr_cpus,
>      for (i = 0; i < nr_cpus; i++) {
>          const char *name;
>
> -        /*
> -         * 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 = (i & 0x0f) | (((i >> 4) & 0xff) << 8);
> +        mpidr_aff = libxl__compute_mpdir(i);
>          name = GCSPRINTF("cpu@%"PRIx64, mpidr_aff);
>
>          res = fdt_begin_node(fdt, name);
> diff --git a/tools/libxl/libxl_arm.h b/tools/libxl/libxl_arm.h
> index fe1c05f..5c8fbc6 100644
> --- a/tools/libxl/libxl_arm.h
> +++ b/tools/libxl/libxl_arm.h
> @@ -35,6 +35,17 @@ static inline int libxl__prepare_acpi(libxl__gc *gc,
>  }
>  #endif
>
> +static inline uint64_t libxl__compute_mpdir(unsigned int cpuid)
> +{
> +    /*
> +     * 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.
> +     */
> +    return (cpuid & 0x0f) | (((cpuid >> 4) & 0xff) << 8);
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
--
Julien Grall

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