Re: [Xen-devel] [PATCH v8 16/24] x86: refactor psr: implement set value callback functions for CDP.

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, Feb 15, 2017 at 04:49:31PM +0800, Yi Sun wrote:
> This patch implements L3 CDP set value related callback functions.
> 
> With this patch, 'psr-cat-cbm-set' command can work for L3 CDP.
> 
> Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
> ---
> v8:
>     - modify 'l3_cdp_write_msr' to 'void'.
> ---
>  xen/arch/x86/psr.c | 118 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 118 insertions(+)
> 
> diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
> index 72ed923..0a0bab9 100644
> --- a/xen/arch/x86/psr.c
> +++ b/xen/arch/x86/psr.c
> @@ -560,10 +560,128 @@ static bool l3_cdp_get_val(const struct feat_node 
> *feat, unsigned int cos,
>      return true;
>  }
>  
> +static unsigned int l3_cdp_get_cos_num(const struct feat_node *feat)
> +{
> +    return 2;

Please avoid using magic number, or document where 2 comes from.

> +}
> +
> +static int l3_cdp_get_old_val(uint64_t val[],

Hmm... so val is indeed an array. I think we need to pass the length as
well.

> +                              const struct feat_node *feat,
> +                              unsigned int old_cos)
> +{
> +    if ( old_cos > feat->info.l3_cdp_info.cos_max )
> +        /* Use default value. */
> +        old_cos = 0;
> +
> +    /* Data */
> +    val[0] = get_cdp_data(feat, old_cos);
> +    /* Code */
> +    val[1] = get_cdp_code(feat, old_cos);
> +
> +    return 0;
> +}
> +
> +static int l3_cdp_set_new_val(uint64_t val[],
> +                              const struct feat_node *feat,
> +                              enum cbm_type type,
> +                              uint64_t m)
> +{
> +    if ( !psr_check_cbm(feat->info.l3_cdp_info.cbm_len, m) )
> +        return -EINVAL;
> +
> +    if ( type == PSR_CBM_TYPE_L3_DATA )
> +        val[0] = m;
> +    else
> +        val[1] = m;
> +
> +    return 0;
> +}
> +
> +static int l3_cdp_compare_val(const uint64_t val[],
> +                              const struct feat_node *feat,
> +                              unsigned int cos, bool *found)
> +{
> +    uint64_t l3_def_cbm;
> +
> +    l3_def_cbm = (1ull << feat->info.l3_cdp_info.cbm_len) - 1;

This is getting repetitive. Please consider providing a macro to
calculate this value.

Wei.

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