Re: [Xen-devel] [PATCH v4 10/24] x86: refactor psr: set value: implement cos finding flow.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.12.16 at 05:07, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> Continue with previous patch, we can try to find if there is a

Please take into consideration that a series may be applied in small
steps. References such as "previous patch" are thus possibly
meaningless. Please instead refer to the patch by title. Also I think
you mean "continue from ...".

> @@ -666,7 +724,58 @@ static int find_cos(const uint64_t *val, uint32_t 
> array_len,
>                      enum cbm_type type,
>                      const struct psr_socket_info *info)
>  {
> -    return 0;
> +    unsigned int cos;
> +    const unsigned int *ref = info->cos_ref;
> +    const struct feat_node *feat_tmp;
> +    const uint64_t *val_tmp = val;
> +    int ret;
> +    bool found = false;
> +    unsigned int cos_max = 0;
> +
> +    /* cos_max is the one of the feature which is being set. */
> +    list_for_each_entry(feat_tmp, &info->feat_list, list)
> +    {
> +        cos_max = feat_tmp->ops.get_cos_max_from_type(feat_tmp, type);
> +        if ( cos_max > 0 )
> +            break;
> +    }
> +
> +    for ( cos = 0; cos <= cos_max; cos++ )
> +    {
> +        if ( cos && !ref[cos] )
> +            continue;
> +
> +        /* Not found, need find again from beginning. */
> +        val_tmp = val;
> +        list_for_each_entry(feat_tmp, &info->feat_list, list)
> +        {
> +            /*
> +             * Compare value according to feature list order.
> +             * We must follow this order because value array is assembled
> +             * as this order in get_old_set_new().
> +             */
> +            ret = feat_tmp->ops.compare_val(val_tmp, feat_tmp, cos, &found);
> +            if ( ret < 0 )
> +                return ret;
> +
> +            /* If fail to match, go to next cos to compare. */
> +            if ( !found )
> +                break;
> +
> +            val_tmp += ret;
> +            if ( val_tmp - val > array_len )
> +                return -EINVAL;
> +        }
> +
> +        /*
> +         * With this cos id, every entry of value array can match. This cos
> +         * is what we find.
> +         */

"can match" seems rather misleading to me. I think you mean
something like "For this COS ID all entries in the values array did
match. Use it."

Other than that various of the comments given for earlier patches
apply here, in particular the fact that the type matching should
move out of the hook functions.

Jan


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