Re: [PATCH v4 04/12] x86: maintain COS to CBM mapping for each socket

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 09/04/2015 10:18, Chao Peng wrote:
> For each socket, a COS to CBM mapping structure is maintained for each
> COS. The mapping is indexed by COS and the value is the corresponding
> CBM. Different VMs may use the same CBM, a reference count is used to
> indicate if the CBM is available.
>
> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
> ---
>  xen/arch/x86/psr.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
> index 16c37dd..4aff5f6 100644
> --- a/xen/arch/x86/psr.c
> +++ b/xen/arch/x86/psr.c
> @@ -21,11 +21,17 @@
>  #define PSR_CMT        (1<<0)
>  #define PSR_CAT        (1<<1)
>  
> +struct psr_cat_cbm {
> +    unsigned int ref;
> +    uint64_t cbm;
> +};
> +
>  struct psr_cat_socket_info {
>      bool_t initialized;
>      bool_t enabled;
>      unsigned int cbm_len;
>      unsigned int cos_max;
> +    struct psr_cat_cbm *cos_cbm_map;

"cos_to_cmb" would be more in keeping with Xen style, and IMO easier to
read in code.

>  };
>  
>  struct psr_assoc {
> @@ -240,6 +246,14 @@ static void cat_cpu_init(unsigned int cpu)
>          info->cbm_len = (eax & 0x1f) + 1;
>          info->cos_max = (edx & 0xffff);

Apologies for missing this in the previous patch, but cos_max should
have a command line parameter like rmid_max if a lower limit wants to be
enforced.

Otherwise, Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

>  
> +        info->cos_cbm_map = xzalloc_array(struct psr_cat_cbm,
> +                                          info->cos_max + 1UL);
> +        if ( !info->cos_cbm_map )
> +            return;
> +
> +        /* cos=0 is reserved as default cbm(all ones). */
> +        info->cos_cbm_map[0].cbm = (1ull << info->cbm_len) - 1;
> +
>          info->enabled = 1;
>          printk(XENLOG_INFO "CAT: enabled on socket %u, cos_max:%u, cbm_len:%u\n",
>                 socket, info->cos_max, info->cbm_len);