Re: [RFC] mpam,x86,fs/resctrl: Generic schema description Proof of Concept

["Chen, Yu C" <yu.c.chen@intel.com>]

Hi Ben,

On 7/2/2026 10:27 PM, Ben Horgan wrote:
> Hi Chenyu,

[ ... ]

>> The following are current thoughts on how Control B can emulate Control A.
>> May I know if this direction is acceptable?
>>
>> The main idea is that, Legacy MBA controller delegates to region-aware MBA
>> controller via a pointer, with its hw_update function converting
>> percentages
>> to the target's value range.
>>
>> struct resctrl_hw_ctrl {
>>      struct resctrl_ctrl  r_ctrl;
>>      unsigned int         msr_base;
>>      void                 (*hw_update)(struct hw_param *m);
>>      /* points to the backing controller */
>>      struct resctrl_ctrl  *r_ctrl_emul;  <-- newly added
>> };
> 
> What's the reason for this being in the architecture specific code? I
> would expect that the resctrl core code would need to know about any
> emulation even if the exact emulation is architecture specific?
> 

I was thinking that the low-level emulation was implemented by the
hardware/architecture, so I put it within resctrl_hw_ctrl. But you
are right - the generic resctrl might need to be aware of the emulation,
because the "info" directory needs to display the emulation hierarchy.
Let me have a try at moving it into the generic resctrl, like into
struct resctrl_ctrl.

thanks,
Chenyu