Re: [Xen-devel] [PATCH v11 12/23] x86: refactor psr: L3 CAT: set value: implement write msr flow.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 03.05.17 at 10:44, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> +struct cos_write_info
> +{
> +    unsigned int cos;
> +    struct feat_node *feature;
> +    uint32_t *val;
> +    enum psr_feat_type feat_type;
> +};
> +
> +static void do_write_psr_msrs(void *data)
> +{
> +    struct cos_write_info *info = data;
> +    unsigned int cos = info->cos;
> +    struct feat_node *feat = info->feature;
> +    const struct feat_props *props = feat_props[info->feat_type];
> +    unsigned int i;
> +
> +    for ( i = 0; i < props->cos_num; i++ )
> +    {
> +        if ( feat->cos_reg_val[cos * props->cos_num + i] != info->val[i] )
> +        {
> +            feat->cos_reg_val[cos * props->cos_num + i] = info->val[i];
> +            props->write_msr(cos, info->val[i], props->type[i]);
> +        }
> +    }
> +}

Again you're passing feat_type here only to get at props. Why
not pass props right away? Also I think it would make sense to
pull props->cos_num into a local variable.

>  static int write_psr_msrs(unsigned int socket, unsigned int cos,
>                            uint32_t val[], unsigned int array_len,
>                            enum psr_feat_type feat_type)
>  {
> -    return -ENOENT;
> +    unsigned int i;
> +    struct psr_socket_info *info = get_socket_info(socket);
> +    struct cos_write_info data =
> +    {
> +        .cos = cos,
> +        .feature = info->features[feat_type],
> +        .feat_type = feat_type,
> +    };
> +
> +    if ( cos > info->features[feat_type]->cos_max )
> +        return -EINVAL;
> +
> +    /* Skip to the feature's value head. */
> +    for ( i = 0; i < feat_type; i++ )
> +    {
> +        if ( !info->features[i] )
> +            continue;

This is inconsistent with checks done elsewhere, where you also
check feat_props[feat_type] against NULL. I've made a comment
regarding whether both checks are wanted in a uniform or non-
uniform way pretty early in the series. Whatever is selected
should then be used consistently.

Jan


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