Re: [PATCH RFC v2 08/17] RISC-V: QoS: add resctrl interface for CBQRI controllers

[guo.wenjia23]

Hi Drew,

On Thu, Jan 29, 2026 at 4:28 AM Drew Fustini <fustini@xxxxxxxxxx> wrote:>
> Add interface for CBQRI controller drivers to make use of the resctrl
> filesystem.
>
> Co-developed-by: Adrien Ricciardi <aricciardi@xxxxxxxxxxxx>
> Signed-off-by: Adrien Ricciardi <aricciardi@xxxxxxxxxxxx>
> Signed-off-by: Drew Fustini <fustini@xxxxxxxxxx>
> ---
> arch/riscv/kernel/qos/qos_resctrl.c | 1192 +++++++++++++++++++++++++++++++++++
> 1 file changed, 1192 insertions(+)
>
> ...
>
> +
> +int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_ctrl_domain *d,
> + u32 closid, enum resctrl_conf_type t, u32 cfg_val)
> +{
> + struct cbqri_controller *ctrl;
> + struct cbqri_resctrl_dom *dom;
> + struct cbqri_config cfg;
> + int err = 0;
> +
> + dom = container_of(d, struct cbqri_resctrl_dom, resctrl_ctrl_dom);
> + ctrl = dom->hw_ctrl;
> +
> + if (!r->alloc_capable)
> + return -EINVAL;
> +
> + switch (r->rid) {
> + case RDT_RESOURCE_L2:
> + case RDT_RESOURCE_L3:
> + cfg.cbm = cfg_val;
> + err = cbqri_apply_cache_config(dom, closid, t, &cfg);
> + break;
> + case RDT_RESOURCE_MBA:
> + /* covert from percentage to bandwidth blocks */
> + cfg.rbwb = cfg_val * ctrl->bc.nbwblks / 100;

Should use bc.mrbwb to calculate rbwb?
I think bc.nbwblks represent the available bw blks in the controller. It should should decrease as they are allocated.

> + err = cbqri_apply_bw_config(dom, closid, t, &cfg);
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return err;
> +}
>
> ...
>
> +u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_ctrl_domain *d,
> + u32 closid, enum resctrl_conf_type type)
> +{
> + struct cbqri_resctrl_dom *hw_dom;
> + struct cbqri_controller *ctrl;
> + int reg_offset;
> + u32 percent;
> + u32 rbwb;
> + u64 reg;
> + int err;
> +
> + hw_dom = container_of(d, struct cbqri_resctrl_dom, resctrl_ctrl_dom);
> +
> + ctrl = hw_dom->hw_ctrl;
> +
> + if (!r->alloc_capable)
> + return resctrl_get_default_ctrl(r);
> +
> + switch (r->rid) {
> + case RDT_RESOURCE_L2:
> + case RDT_RESOURCE_L3:
> + /* Clear cc_block_mask before read limit operation */
> + cbqri_set_cbm(ctrl, 0);
> +
> + /* Capacity read limit operation for RCID (closid) */
> + err = cbqri_cc_alloc_op(ctrl, CBQRI_CC_ALLOC_CTL_OP_READ_LIMIT, type, closid);
> + if (err < 0) {
> + pr_err("%s(): operation failed: err = %d", __func__, err);
> + return resctrl_get_default_ctrl(r);
> + }
> +
> + /* Read capacity block mask for RCID (closid) */
> + reg_offset = CBQRI_CC_BLOCK_MASK_OFF;
> + reg = ioread64(ctrl->base + reg_offset);
> +
> + /* Update the config value for the closid in this domain */
> + hw_dom->ctrl_val[closid] = reg;
> + return hw_dom->ctrl_val[closid];
> +
> + case RDT_RESOURCE_MBA:
> + /* Capacity read limit operation for RCID (closid) */
> + err = cbqri_bc_alloc_op(ctrl, CBQRI_CC_ALLOC_CTL_OP_READ_LIMIT, closid);
> + if (err < 0) {
> + pr_err("%s(): operation failed: err = %d", __func__, err);
> + return resctrl_get_default_ctrl(r);
> + }
> +
> + hw_dom->ctrl_val[closid] = cbqri_get_rbwb(ctrl);
> +
> + /* Convert from bandwidth blocks to percent */
> + rbwb = hw_dom->ctrl_val[closid];
> + rbwb *= 100;
> + percent = rbwb / ctrl->bc.nbwblks;
> + if (rbwb % ctrl->bc.nbwblks)

Same Question.

> + percent++;
> + return percent;
> +
> + default:
> + return resctrl_get_default_ctrl(r);
> + }
> +}

Sorry for my previous reply on old patch. Please ignore it. I’m re-sending this comment on v2.

Thank,
Wenjia





郭文佳10158971