[PATCH v3 20/29] arm_mpam: Allow configuration to be applied and restored during cpu online

[Ben Horgan]

Hi James,

On 10/17/25 19:56, James Morse wrote:
> When CPUs come online the MSC's original configuration should be restored.
> 
> Add struct mpam_config to hold the configuration. This has a bitmap of
> features that were modified. Once the maximum partid is known, allocate
> a configuration array for each component, and reprogram each RIS
> configuration from this.
> 
> CC: Dave Martin <Dave.Martin at arm.com>
> Signed-off-by: James Morse <james.morse at arm.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron at huawei.com>
> Reviewed-by: Ben Horgan <ben.horgan at arm.com>
> Tested-by: Fenghua Yu <fenghuay at nvidia.com>
> ---
> Changes since v2:
>  * Call mpam_init_reset_cfg() on alloated config as 0 is not longer correct.
>  * init_garbage() on each config - the array has to be freed in one go, but
>    otherwise this looks weird.
>  * Use struct initialiser in mpam_init_reset_cfg(),
>  * Moved int err definition.
>  * Removed srcu lock taking based on squinting at the only caller.
>  * Moved config reset to mpam_reset_component_cfg() for re-use in
>    mpam_reset_component_locked(), previous memset() was not enough since zero
>    no longer means reset.
> 
[...]
>  
> +struct reprogram_ris {
> +	struct mpam_msc_ris *ris;
> +	struct mpam_config *cfg;
> +};
> +
> +/* Call with MSC lock held */
> +static int mpam_reprogram_ris(void *_arg)
> +{
> +	u16 partid, partid_max;
> +	struct reprogram_ris *arg = _arg;
> +	struct mpam_msc_ris *ris = arg->ris;
> +	struct mpam_config *cfg = arg->cfg;
> +
> +	if (ris->in_reset_state)
> +		return 0;
> +
> +	spin_lock(&partid_max_lock);
> +	partid_max = mpam_partid_max;
> +	spin_unlock(&partid_max_lock);
> +	for (partid = 0; partid <= partid_max + 1; partid++)

Loop overrun. This was correct in the previous version of the patch and
the same shape of loop is done correctly elsewhere in this version. I
think it would be good to standardise on using either:
partid <= partid_max
or
partid < partid_max + 1
I have a preference for the first as you don't need to think about the
size of the type.

-- 
Thanks,

Ben