// SPDX-License-Identifier: GPL-2.0-only
/*
 * Resource Director Technology(RDT)
 * - Cache Allocation code.
 *
 * Copyright (C) 2016 Intel Corporation
 *
 * Authors:
 *    Fenghua Yu <fenghua.yu@intel.com>
 *    Tony Luck <tony.luck@intel.com>
 *
 * More information about RDT be found in the Intel (R) x86 Architecture
 * Software Developer Manual June 2016, volume 3, section 17.17.
 */

#define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/kernfs.h>
#include <linux/math.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/tick.h>

#include "internal.h"

struct rdt_parse_data {
        u32                     closid;
        enum rdtgrp_mode        mode;
        char                    *buf;
};

typedef int (ctrlval_parser_t)(struct rdt_parse_data *data,
                               struct resctrl_schema *s,
                               struct rdt_ctrl_domain *d);

/*
 * Check whether MBA bandwidth percentage value is correct. The value is
 * checked against the minimum and max bandwidth values specified by the
 * hardware. The allocated bandwidth percentage is rounded to the next
 * control step available on the hardware.
 */
static bool bw_validate(char *buf, u32 *data, struct rdt_resource *r)
{
        int ret;
        u32 bw;

        /*
         * Only linear delay values is supported for current Intel SKUs.
         */
        if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
                rdt_last_cmd_puts("No support for non-linear MB domains\n");
                return false;
        }

        ret = kstrtou32(buf, 10, &bw);
        if (ret) {
                rdt_last_cmd_printf("Invalid MB value %s\n", buf);
                return false;
        }

        /* Nothing else to do if software controller is enabled. */
        if (is_mba_sc(r)) {
                *data = bw;
                return true;
        }

        if (bw < r->membw.min_bw || bw > r->membw.max_bw) {
                rdt_last_cmd_printf("MB value %u out of range [%d,%d]\n",
                                    bw, r->membw.min_bw, r->membw.max_bw);
                return false;
        }

        *data = roundup(bw, (unsigned long)r->membw.bw_gran);
        return true;
}

static int parse_bw(struct rdt_parse_data *data, struct resctrl_schema *s,
                    struct rdt_ctrl_domain *d)
{
        struct resctrl_staged_config *cfg;
        struct rdt_resource *r = s->res;
        u32 closid = data->closid;
        u32 bw_val;

        cfg = &d->staged_config[s->conf_type];
        if (cfg->have_new_ctrl) {
                rdt_last_cmd_printf("Duplicate domain %d\n", d->hdr.id);
                return -EINVAL;
        }

        if (!bw_validate(data->buf, &bw_val, r))
                return -EINVAL;

        if (is_mba_sc(r)) {
                d->mbps_val[closid] = bw_val;
                return 0;
        }

        cfg->new_ctrl = bw_val;
        cfg->have_new_ctrl = true;

        return 0;
}

/*
 * Check whether a cache bit mask is valid.
 * On Intel CPUs, non-contiguous 1s value support is indicated by CPUID:
 *   - CPUID.0x10.1:ECX[3]: L3 non-contiguous 1s value supported if 1
 *   - CPUID.0x10.2:ECX[3]: L2 non-contiguous 1s value supported if 1
 *
 * Haswell does not support a non-contiguous 1s value and additionally
 * requires at least two bits set.
 * AMD allows non-contiguous bitmasks.
 */
static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
{
        u32 supported_bits = BIT_MASK(r->cache.cbm_len) - 1;
        unsigned int cbm_len = r->cache.cbm_len;
        unsigned long first_bit, zero_bit, val;
        int ret;

        ret = kstrtoul(buf, 16, &val);
        if (ret) {
                rdt_last_cmd_printf("Non-hex character in the mask %s\n", buf);
                return false;
        }

        if ((r->cache.min_cbm_bits > 0 && val == 0) || val > supported_bits) {
                rdt_last_cmd_puts("Mask out of range\n");
                return false;
        }

        first_bit = find_first_bit(&val, cbm_len);
        zero_bit = find_next_zero_bit(&val, cbm_len, first_bit);

        /* Are non-contiguous bitmasks allowed? */
        if (!r->cache.arch_has_sparse_bitmasks &&
            (find_next_bit(&val, cbm_len, zero_bit) < cbm_len)) {
                rdt_last_cmd_printf("The mask %lx has non-consecutive 1-bits\n", val);
                return false;
        }

        if ((zero_bit - first_bit) < r->cache.min_cbm_bits) {
                rdt_last_cmd_printf("Need at least %d bits in the mask\n",
                                    r->cache.min_cbm_bits);
                return false;
        }

        *data = val;
        return true;
}

/*
 * Read one cache bit mask (hex). Check that it is valid for the current
 * resource type.
 */
static int parse_cbm(struct rdt_parse_data *data, struct resctrl_schema *s,
                     struct rdt_ctrl_domain *d)
{
        enum rdtgrp_mode mode = data->mode;
        struct resctrl_staged_config *cfg;
        struct rdt_resource *r = s->res;
        u32 closid = data->closid;
        u32 cbm_val;

        cfg = &d->staged_config[s->conf_type];
        if (cfg->have_new_ctrl) {
                rdt_last_cmd_printf("Duplicate domain %d\n", d->hdr.id);
                return -EINVAL;
        }

        /*
         * Cannot set up more than one pseudo-locked region in a cache
         * hierarchy.
         */
        if (mode == RDT_MODE_PSEUDO_LOCKSETUP &&
            rdtgroup_pseudo_locked_in_hierarchy(d)) {
                rdt_last_cmd_puts("Pseudo-locked region in hierarchy\n");
                return -EINVAL;
        }

        if (!cbm_validate(data->buf, &cbm_val, r))
                return -EINVAL;

        if ((mode == RDT_MODE_EXCLUSIVE || mode == RDT_MODE_SHAREABLE) &&
            rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
                rdt_last_cmd_puts("CBM overlaps with pseudo-locked region\n");
                return -EINVAL;
        }

        /*
         * The CBM may not overlap with the CBM of another closid if
         * either is exclusive.
         */
        if (rdtgroup_cbm_overlaps(s, d, cbm_val, closid, true)) {
                rdt_last_cmd_puts("Overlaps with exclusive group\n");
                return -EINVAL;
        }

        if (rdtgroup_cbm_overlaps(s, d, cbm_val, closid, false)) {
                if (mode == RDT_MODE_EXCLUSIVE ||
                    mode == RDT_MODE_PSEUDO_LOCKSETUP) {
                        rdt_last_cmd_puts("Overlaps with other group\n");
                        return -EINVAL;
                }
        }

        cfg->new_ctrl = cbm_val;
        cfg->have_new_ctrl = true;

        return 0;
}

/*
 * For each domain in this resource we expect to find a series of:
 *      id=mask
 * separated by ";". The "id" is in decimal, and must match one of
 * the "id"s for this resource.
 */
static int parse_line(char *line, struct resctrl_schema *s,
                      struct rdtgroup *rdtgrp)
{
        enum resctrl_conf_type t = s->conf_type;
        ctrlval_parser_t *parse_ctrlval = NULL;
        struct resctrl_staged_config *cfg;
        struct rdt_resource *r = s->res;
        struct rdt_parse_data data;
        struct rdt_ctrl_domain *d;
        char *dom = NULL, *id;
        unsigned long dom_id;

        /* Walking r->domains, ensure it can't race with cpuhp */
        lockdep_assert_cpus_held();

        switch (r->schema_fmt) {
        case RESCTRL_SCHEMA_BITMAP:
                parse_ctrlval = &parse_cbm;
                break;
        case RESCTRL_SCHEMA_RANGE:
                parse_ctrlval = &parse_bw;
                break;
        }

        if (WARN_ON_ONCE(!parse_ctrlval))
                return -EINVAL;

        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
            (r->rid == RDT_RESOURCE_MBA || r->rid == RDT_RESOURCE_SMBA)) {
                rdt_last_cmd_puts("Cannot pseudo-lock MBA resource\n");
                return -EINVAL;
        }

next:
        if (!line || line[0] == '\0')
                return 0;
        dom = strsep(&line, ";");
        id = strsep(&dom, "=");
        if (!dom || kstrtoul(id, 10, &dom_id)) {
                rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");
                return -EINVAL;
        }
        dom = strim(dom);
        list_for_each_entry(d, &r->ctrl_domains, hdr.list) {
                if (d->hdr.id == dom_id) {
                        data.buf = dom;
                        data.closid = rdtgrp->closid;
                        data.mode = rdtgrp->mode;
                        if (parse_ctrlval(&data, s, d))
                                return -EINVAL;
                        if (rdtgrp->mode ==  RDT_MODE_PSEUDO_LOCKSETUP) {
                                cfg = &d->staged_config[t];
                                /*
                                 * In pseudo-locking setup mode and just
                                 * parsed a valid CBM that should be
                                 * pseudo-locked. Only one locked region per
                                 * resource group and domain so just do
                                 * the required initialization for single
                                 * region and return.
                                 */
                                rdtgrp->plr->s = s;
                                rdtgrp->plr->d = d;
                                rdtgrp->plr->cbm = cfg->new_ctrl;
                                d->plr = rdtgrp->plr;
                                return 0;
                        }
                        goto next;
                }
        }
        return -EINVAL;
}

static int rdtgroup_parse_resource(char *resname, char *tok,
                                   struct rdtgroup *rdtgrp)
{
        struct resctrl_schema *s;

        list_for_each_entry(s, &resctrl_schema_all, list) {
                if (!strcmp(resname, s->name) && rdtgrp->closid < s->num_closid)
                        return parse_line(tok, s, rdtgrp);
        }
        rdt_last_cmd_printf("Unknown or unsupported resource name '%s'\n", resname);
        return -EINVAL;
}

ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
                                char *buf, size_t nbytes, loff_t off)
{
        struct resctrl_schema *s;
        struct rdtgroup *rdtgrp;
        struct rdt_resource *r;
        char *tok, *resname;
        int ret = 0;

        /* Valid input requires a trailing newline */
        if (nbytes == 0 || buf[nbytes - 1] != '\n')
                return -EINVAL;
        buf[nbytes - 1] = '\0';

        rdtgrp = rdtgroup_kn_lock_live(of->kn);
        if (!rdtgrp) {
                rdtgroup_kn_unlock(of->kn);
                return -ENOENT;
        }
        rdt_last_cmd_clear();

        /*
         * No changes to pseudo-locked region allowed. It has to be removed
         * and re-created instead.
         */
        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
                ret = -EINVAL;
                rdt_last_cmd_puts("Resource group is pseudo-locked\n");
                goto out;
        }

        rdt_staged_configs_clear();

        while ((tok = strsep(&buf, "\n")) != NULL) {
                resname = strim(strsep(&tok, ":"));
                if (!tok) {
                        rdt_last_cmd_puts("Missing ':'\n");
                        ret = -EINVAL;
                        goto out;
                }
                if (tok[0] == '\0') {
                        rdt_last_cmd_printf("Missing '%s' value\n", resname);
                        ret = -EINVAL;
                        goto out;
                }
                ret = rdtgroup_parse_resource(resname, tok, rdtgrp);
                if (ret)
                        goto out;
        }

        list_for_each_entry(s, &resctrl_schema_all, list) {
                r = s->res;

                /*
                 * Writes to mba_sc resources update the software controller,
                 * not the control MSR.
                 */
                if (is_mba_sc(r))
                        continue;

                ret = resctrl_arch_update_domains(r, rdtgrp->closid);
                if (ret)
                        goto out;
        }

        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
                /*
                 * If pseudo-locking fails we keep the resource group in
                 * mode RDT_MODE_PSEUDO_LOCKSETUP with its class of service
                 * active and updated for just the domain the pseudo-locked
                 * region was requested for.
                 */
                ret = rdtgroup_pseudo_lock_create(rdtgrp);
        }

out:
        rdt_staged_configs_clear();
        rdtgroup_kn_unlock(of->kn);
        return ret ?: nbytes;
}

static void show_doms(struct seq_file *s, struct resctrl_schema *schema,
                      char *resource_name, int closid)
{
        struct rdt_resource *r = schema->res;
        struct rdt_ctrl_domain *dom;
        bool sep = false;
        u32 ctrl_val;

        /* Walking r->domains, ensure it can't race with cpuhp */
        lockdep_assert_cpus_held();

        if (resource_name)
                seq_printf(s, "%*s:", max_name_width, resource_name);
        list_for_each_entry(dom, &r->ctrl_domains, hdr.list) {
                if (sep)
                        seq_puts(s, ";");

                if (is_mba_sc(r))
                        ctrl_val = dom->mbps_val[closid];
                else
                        ctrl_val = resctrl_arch_get_config(r, dom, closid,
                                                           schema->conf_type);

                seq_printf(s, schema->fmt_str, dom->hdr.id, ctrl_val);
                sep = true;
        }
        seq_puts(s, "\n");
}

int rdtgroup_schemata_show(struct kernfs_open_file *of,
                           struct seq_file *s, void *v)
{
        struct resctrl_schema *schema;
        struct rdtgroup *rdtgrp;
        int ret = 0;
        u32 closid;

        rdtgrp = rdtgroup_kn_lock_live(of->kn);
        if (rdtgrp) {
                if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
                        list_for_each_entry(schema, &resctrl_schema_all, list) {
                                seq_printf(s, "%s:uninitialized\n", schema->name);
                        }
                } else if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
                        if (!rdtgrp->plr->d) {
                                rdt_last_cmd_clear();
                                rdt_last_cmd_puts("Cache domain offline\n");
                                ret = -ENODEV;
                        } else {
                                seq_printf(s, "%s:%d=%x\n",
                                           rdtgrp->plr->s->res->name,
                                           rdtgrp->plr->d->hdr.id,
                                           rdtgrp->plr->cbm);
                        }
                } else {
                        closid = rdtgrp->closid;
                        list_for_each_entry(schema, &resctrl_schema_all, list) {
                                if (closid < schema->num_closid)
                                        show_doms(s, schema, schema->name, closid);
                        }
                }
        } else {
                ret = -ENOENT;
        }
        rdtgroup_kn_unlock(of->kn);
        return ret;
}

static int smp_mon_event_count(void *arg)
{
        mon_event_count(arg);

        return 0;
}

ssize_t rdtgroup_mba_mbps_event_write(struct kernfs_open_file *of,
                                      char *buf, size_t nbytes, loff_t off)
{
        struct rdtgroup *rdtgrp;
        int ret = 0;

        /* Valid input requires a trailing newline */
        if (nbytes == 0 || buf[nbytes - 1] != '\n')
                return -EINVAL;
        buf[nbytes - 1] = '\0';

        rdtgrp = rdtgroup_kn_lock_live(of->kn);
        if (!rdtgrp) {
                rdtgroup_kn_unlock(of->kn);
                return -ENOENT;
        }
        rdt_last_cmd_clear();

        if (!strcmp(buf, "mbm_local_bytes")) {
                if (resctrl_is_mon_event_enabled(QOS_L3_MBM_LOCAL_EVENT_ID))
                        rdtgrp->mba_mbps_event = QOS_L3_MBM_LOCAL_EVENT_ID;
                else
                        ret = -EINVAL;
        } else if (!strcmp(buf, "mbm_total_bytes")) {
                if (resctrl_is_mon_event_enabled(QOS_L3_MBM_TOTAL_EVENT_ID))
                        rdtgrp->mba_mbps_event = QOS_L3_MBM_TOTAL_EVENT_ID;
                else
                        ret = -EINVAL;
        } else {
                ret = -EINVAL;
        }

        if (ret)
                rdt_last_cmd_printf("Unsupported event id '%s'\n", buf);

        rdtgroup_kn_unlock(of->kn);

        return ret ?: nbytes;
}

int rdtgroup_mba_mbps_event_show(struct kernfs_open_file *of,
                                 struct seq_file *s, void *v)
{
        struct rdtgroup *rdtgrp;
        int ret = 0;

        rdtgrp = rdtgroup_kn_lock_live(of->kn);

        if (rdtgrp) {
                switch (rdtgrp->mba_mbps_event) {
                case QOS_L3_MBM_LOCAL_EVENT_ID:
                        seq_puts(s, "mbm_local_bytes\n");
                        break;
                case QOS_L3_MBM_TOTAL_EVENT_ID:
                        seq_puts(s, "mbm_total_bytes\n");
                        break;
                default:
                        pr_warn_once("Bad event %d\n", rdtgrp->mba_mbps_event);
                        ret = -EINVAL;
                        break;
                }
        } else {
                ret = -ENOENT;
        }

        rdtgroup_kn_unlock(of->kn);

        return ret;
}

struct rdt_domain_hdr *resctrl_find_domain(struct list_head *h, int id,
                                           struct list_head **pos)
{
        struct rdt_domain_hdr *d;
        struct list_head *l;

        list_for_each(l, h) {
                d = list_entry(l, struct rdt_domain_hdr, list);
                /* When id is found, return its domain. */
                if (id == d->id)
                        return d;
                /* Stop searching when finding id's position in sorted list. */
                if (id < d->id)
                        break;
        }

        if (pos)
                *pos = l;

        return NULL;
}

void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
                    struct rdt_domain_hdr *hdr, struct rdtgroup *rdtgrp,
                    cpumask_t *cpumask, struct mon_evt *evt, int first)
{
        int cpu;

        /* When picking a CPU from cpu_mask, ensure it can't race with cpuhp */
        lockdep_assert_cpus_held();

        /*
         * Setup the parameters to pass to mon_event_count() to read the data.
         */
        rr->rgrp = rdtgrp;
        rr->evt = evt;
        rr->r = r;
        rr->hdr = hdr;
        rr->first = first;
        if (resctrl_arch_mbm_cntr_assign_enabled(r) &&
            resctrl_is_mbm_event(evt->evtid)) {
                rr->is_mbm_cntr = true;
        } else {
                rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evt->evtid);
                if (IS_ERR(rr->arch_mon_ctx)) {
                        rr->err = -EINVAL;
                        return;
                }
        }

        if (evt->any_cpu) {
                mon_event_count(rr);
                goto out_ctx_free;
        }

        cpu = cpumask_any_housekeeping(cpumask, RESCTRL_PICK_ANY_CPU);

        /*
         * cpumask_any_housekeeping() prefers housekeeping CPUs, but
         * are all the CPUs nohz_full? If yes, pick a CPU to IPI.
         * MPAM's resctrl_arch_rmid_read() is unable to read the
         * counters on some platforms if its called in IRQ context.
         */
        if (tick_nohz_full_cpu(cpu))
                smp_call_function_any(cpumask, mon_event_count, rr, 1);
        else
                smp_call_on_cpu(cpu, smp_mon_event_count, rr, false);

out_ctx_free:
        if (rr->arch_mon_ctx)
                resctrl_arch_mon_ctx_free(r, evt->evtid, rr->arch_mon_ctx);
}

/*
 * Decimal place precision to use for each number of fixed-point
 * binary bits computed from ceil(binary_bits * log10(2)) except
 * binary_bits == 0 which will print "value.0"
 */
static const unsigned int decplaces[MAX_BINARY_BITS + 1] = {
        [0]  =  1,
        [1]  =  1,
        [2]  =  1,
        [3]  =  1,
        [4]  =  2,
        [5]  =  2,
        [6]  =  2,
        [7]  =  3,
        [8]  =  3,
        [9]  =  3,
        [10] =  4,
        [11] =  4,
        [12] =  4,
        [13] =  4,
        [14] =  5,
        [15] =  5,
        [16] =  5,
        [17] =  6,
        [18] =  6,
        [19] =  6,
        [20] =  7,
        [21] =  7,
        [22] =  7,
        [23] =  7,
        [24] =  8,
        [25] =  8,
        [26] =  8,
        [27] =  9
};

static void print_event_value(struct seq_file *m, unsigned int binary_bits, u64 val)
{
        unsigned long long frac = 0;

        if (binary_bits) {
                /* Mask off the integer part of the fixed-point value. */
                frac = val & GENMASK_ULL(binary_bits - 1, 0);

                /*
                 * Multiply by 10^{desired decimal places}. The integer part of
                 * the fixed point value is now almost what is needed.
                 */
                frac *= int_pow(10ull, decplaces[binary_bits]);

                /*
                 * Round to nearest by adding a value that would be a "1" in the
                 * binary_bits + 1 place.  Integer part of fixed point value is
                 * now the needed value.
                 */
                frac += 1ull << (binary_bits - 1);

                /*
                 * Extract the integer part of the value. This is the decimal
                 * representation of the original fixed-point fractional value.
                 */
                frac >>= binary_bits;
        }

        /*
         * "frac" is now in the range [0 .. 10^decplaces).  I.e. string
         * representation will fit into chosen number of decimal places.
         */
        seq_printf(m, "%llu.%0*llu\n", val >> binary_bits, decplaces[binary_bits], frac);
}

int rdtgroup_mondata_show(struct seq_file *m, void *arg)
{
        struct kernfs_open_file *of = m->private;
        enum resctrl_res_level resid;
        struct rdt_domain_hdr *hdr;
        struct rmid_read rr = {0};
        struct rdtgroup *rdtgrp;
        int domid, cpu, ret = 0;
        struct rdt_resource *r;
        struct cacheinfo *ci;
        struct mon_evt *evt;
        struct mon_data *md;

        rdtgrp = rdtgroup_kn_lock_live(of->kn);
        if (!rdtgrp) {
                ret = -ENOENT;
                goto out;
        }

        md = of->kn->priv;
        if (WARN_ON_ONCE(!md)) {
                ret = -EIO;
                goto out;
        }

        resid = md->rid;
        domid = md->domid;
        evt = md->evt;
        r = resctrl_arch_get_resource(resid);

        if (md->sum) {
                struct rdt_l3_mon_domain *d;

                if (WARN_ON_ONCE(resid != RDT_RESOURCE_L3)) {
                        ret = -EINVAL;
                        goto out;
                }

                /*
                 * This file requires summing across all domains that share
                 * the L3 cache id that was provided in the "domid" field of the
                 * struct mon_data. Search all domains in the resource for
                 * one that matches this cache id.
                 */
                list_for_each_entry(d, &r->mon_domains, hdr.list) {
                        if (d->ci_id == domid) {
                                cpu = cpumask_any(&d->hdr.cpu_mask);
                                ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE);
                                if (!ci)
                                        continue;
                                rr.ci = ci;
                                mon_event_read(&rr, r, NULL, rdtgrp,
                                               &ci->shared_cpu_map, evt, false);
                                goto checkresult;
                        }
                }
                ret = -ENOENT;
                goto out;
        } else {
                /*
                 * This file provides data from a single domain. Search
                 * the resource to find the domain with "domid".
                 */
                hdr = resctrl_find_domain(&r->mon_domains, domid, NULL);
                if (!hdr) {
                        ret = -ENOENT;
                        goto out;
                }
                mon_event_read(&rr, r, hdr, rdtgrp, &hdr->cpu_mask, evt, false);
        }

checkresult:

        /*
         * -ENOENT is a special case, set only when "mbm_event" counter assignment
         * mode is enabled and no counter has been assigned.
         */
        if (rr.err == -EIO)
                seq_puts(m, "Error\n");
        else if (rr.err == -EINVAL)
                seq_puts(m, "Unavailable\n");
        else if (rr.err == -ENOENT)
                seq_puts(m, "Unassigned\n");
        else if (evt->is_floating_point)
                print_event_value(m, evt->binary_bits, rr.val);
        else
                seq_printf(m, "%llu\n", rr.val);

out:
        rdtgroup_kn_unlock(of->kn);
        return ret;
}

int resctrl_io_alloc_show(struct kernfs_open_file *of, struct seq_file *seq, void *v)
{
        struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
        struct rdt_resource *r = s->res;

        mutex_lock(&rdtgroup_mutex);

        if (r->cache.io_alloc_capable) {
                if (resctrl_arch_get_io_alloc_enabled(r))
                        seq_puts(seq, "enabled\n");
                else
                        seq_puts(seq, "disabled\n");
        } else {
                seq_puts(seq, "not supported\n");
        }

        mutex_unlock(&rdtgroup_mutex);

        return 0;
}

/*
 * resctrl_io_alloc_closid_supported() - io_alloc feature utilizes the
 * highest CLOSID value to direct I/O traffic. Ensure that io_alloc_closid
 * is in the supported range.
 */
static bool resctrl_io_alloc_closid_supported(u32 io_alloc_closid)
{
        return io_alloc_closid < closids_supported();
}

/*
 * Initialize io_alloc CLOSID cache resource CBM with all usable (shared
 * and unused) cache portions.
 */
static int resctrl_io_alloc_init_cbm(struct resctrl_schema *s, u32 closid)
{
        enum resctrl_conf_type peer_type;
        struct rdt_resource *r = s->res;
        struct rdt_ctrl_domain *d;
        int ret;

        rdt_staged_configs_clear();

        ret = rdtgroup_init_cat(s, closid);
        if (ret < 0)
                goto out;

        /* Keep CDP_CODE and CDP_DATA of io_alloc CLOSID's CBM in sync. */
        if (resctrl_arch_get_cdp_enabled(r->rid)) {
                peer_type = resctrl_peer_type(s->conf_type);
                list_for_each_entry(d, &s->res->ctrl_domains, hdr.list)
                        memcpy(&d->staged_config[peer_type],
                               &d->staged_config[s->conf_type],
                               sizeof(d->staged_config[0]));
        }

        ret = resctrl_arch_update_domains(r, closid);
out:
        rdt_staged_configs_clear();
        return ret;
}

/*
 * resctrl_io_alloc_closid() - io_alloc feature routes I/O traffic using
 * the highest available CLOSID. Retrieve the maximum CLOSID supported by the
 * resource. Note that if Code Data Prioritization (CDP) is enabled, the number
 * of available CLOSIDs is reduced by half.
 */
u32 resctrl_io_alloc_closid(struct rdt_resource *r)
{
        if (resctrl_arch_get_cdp_enabled(r->rid))
                return resctrl_arch_get_num_closid(r) / 2  - 1;
        else
                return resctrl_arch_get_num_closid(r) - 1;
}

ssize_t resctrl_io_alloc_write(struct kernfs_open_file *of, char *buf,
                               size_t nbytes, loff_t off)
{
        struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
        struct rdt_resource *r = s->res;
        char const *grp_name;
        u32 io_alloc_closid;
        bool enable;
        int ret;

        ret = kstrtobool(buf, &enable);
        if (ret)
                return ret;

        cpus_read_lock();
        mutex_lock(&rdtgroup_mutex);

        rdt_last_cmd_clear();

        if (!r->cache.io_alloc_capable) {
                rdt_last_cmd_printf("io_alloc is not supported on %s\n", s->name);
                ret = -ENODEV;
                goto out_unlock;
        }

        /* If the feature is already up to date, no action is needed. */
        if (resctrl_arch_get_io_alloc_enabled(r) == enable)
                goto out_unlock;

        io_alloc_closid = resctrl_io_alloc_closid(r);
        if (!resctrl_io_alloc_closid_supported(io_alloc_closid)) {
                rdt_last_cmd_printf("io_alloc CLOSID (ctrl_hw_id) %u is not available\n",
                                    io_alloc_closid);
                ret = -EINVAL;
                goto out_unlock;
        }

        if (enable) {
                if (!closid_alloc_fixed(io_alloc_closid)) {
                        grp_name = rdtgroup_name_by_closid(io_alloc_closid);
                        WARN_ON_ONCE(!grp_name);
                        rdt_last_cmd_printf("CLOSID (ctrl_hw_id) %u for io_alloc is used by %s group\n",
                                            io_alloc_closid, grp_name ? grp_name : "another");
                        ret = -ENOSPC;
                        goto out_unlock;
                }

                ret = resctrl_io_alloc_init_cbm(s, io_alloc_closid);
                if (ret) {
                        rdt_last_cmd_puts("Failed to initialize io_alloc allocations\n");
                        closid_free(io_alloc_closid);
                        goto out_unlock;
                }
        } else {
                closid_free(io_alloc_closid);
        }

        ret = resctrl_arch_io_alloc_enable(r, enable);
        if (enable && ret) {
                rdt_last_cmd_puts("Failed to enable io_alloc feature\n");
                closid_free(io_alloc_closid);
        }

out_unlock:
        mutex_unlock(&rdtgroup_mutex);
        cpus_read_unlock();

        return ret ?: nbytes;
}

int resctrl_io_alloc_cbm_show(struct kernfs_open_file *of, struct seq_file *seq, void *v)
{
        struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
        struct rdt_resource *r = s->res;
        int ret = 0;

        cpus_read_lock();
        mutex_lock(&rdtgroup_mutex);

        rdt_last_cmd_clear();

        if (!r->cache.io_alloc_capable) {
                rdt_last_cmd_printf("io_alloc is not supported on %s\n", s->name);
                ret = -ENODEV;
                goto out_unlock;
        }

        if (!resctrl_arch_get_io_alloc_enabled(r)) {
                rdt_last_cmd_printf("io_alloc is not enabled on %s\n", s->name);
                ret = -EINVAL;
                goto out_unlock;
        }

        /*
         * When CDP is enabled, the CBMs of the highest CLOSID of CDP_CODE and
         * CDP_DATA are kept in sync. As a result, the io_alloc CBMs shown for
         * either CDP resource are identical and accurately represent the CBMs
         * used for I/O.
         */
        show_doms(seq, s, NULL, resctrl_io_alloc_closid(r));

out_unlock:
        mutex_unlock(&rdtgroup_mutex);
        cpus_read_unlock();
        return ret;
}

static int resctrl_io_alloc_parse_line(char *line,  struct rdt_resource *r,
                                       struct resctrl_schema *s, u32 closid)
{
        enum resctrl_conf_type peer_type;
        struct rdt_parse_data data;
        struct rdt_ctrl_domain *d;
        char *dom = NULL, *id;
        unsigned long dom_id;

next:
        if (!line || line[0] == '\0')
                return 0;

        dom = strsep(&line, ";");
        id = strsep(&dom, "=");
        if (!dom || kstrtoul(id, 10, &dom_id)) {
                rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");
                return -EINVAL;
        }

        dom = strim(dom);
        list_for_each_entry(d, &r->ctrl_domains, hdr.list) {
                if (d->hdr.id == dom_id) {
                        data.buf = dom;
                        data.mode = RDT_MODE_SHAREABLE;
                        data.closid = closid;
                        if (parse_cbm(&data, s, d))
                                return -EINVAL;
                        /*
                         * Keep io_alloc CLOSID's CBM of CDP_CODE and CDP_DATA
                         * in sync.
                         */
                        if (resctrl_arch_get_cdp_enabled(r->rid)) {
                                peer_type = resctrl_peer_type(s->conf_type);
                                memcpy(&d->staged_config[peer_type],
                                       &d->staged_config[s->conf_type],
                                       sizeof(d->staged_config[0]));
                        }
                        goto next;
                }
        }

        return -EINVAL;
}

ssize_t resctrl_io_alloc_cbm_write(struct kernfs_open_file *of, char *buf,
                                   size_t nbytes, loff_t off)
{
        struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
        struct rdt_resource *r = s->res;
        u32 io_alloc_closid;
        int ret = 0;

        /* Valid input requires a trailing newline */
        if (nbytes == 0 || buf[nbytes - 1] != '\n')
                return -EINVAL;

        buf[nbytes - 1] = '\0';

        cpus_read_lock();
        mutex_lock(&rdtgroup_mutex);
        rdt_last_cmd_clear();

        if (!r->cache.io_alloc_capable) {
                rdt_last_cmd_printf("io_alloc is not supported on %s\n", s->name);
                ret = -ENODEV;
                goto out_unlock;
        }

        if (!resctrl_arch_get_io_alloc_enabled(r)) {
                rdt_last_cmd_printf("io_alloc is not enabled on %s\n", s->name);
                ret = -EINVAL;
                goto out_unlock;
        }

        io_alloc_closid = resctrl_io_alloc_closid(r);

        rdt_staged_configs_clear();
        ret = resctrl_io_alloc_parse_line(buf, r, s, io_alloc_closid);
        if (ret)
                goto out_clear_configs;

        ret = resctrl_arch_update_domains(r, io_alloc_closid);

out_clear_configs:
        rdt_staged_configs_clear();
out_unlock:
        mutex_unlock(&rdtgroup_mutex);
        cpus_read_unlock();

        return ret ?: nbytes;
}