/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2016 by Delphix. All rights reserved.
 */

#include <sys/systm.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/thread.h>
#include <sys/cpuvar.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/policy.h>
#include <sys/group.h>
#include <sys/pg.h>
#include <sys/pghw.h>
#include <sys/cpu_pm.h>
#include <sys/cap_util.h>

/*
 * Processor Groups: Hardware sharing relationship layer
 *
 * This file implements an extension to Processor Groups to capture
 * hardware sharing relationships existing between logical CPUs. Examples of
 * hardware sharing relationships include shared caches on some CMT
 * procesoor architectures, or shared local memory controllers on NUMA
 * based system architectures.
 *
 * The pghw_t structure represents the extended PG. The first member
 * of the structure is the generic pg_t with the pghw specific members
 * following. The generic pg_t *must* remain the first member of the
 * structure as the code uses casting of structure references to access
 * the generic pg_t structure elements.
 *
 * In addition to the generic CPU grouping, physical PGs have a hardware
 * sharing relationship enumerated "type", and an instance id. The enumerated
 * type is defined by the pghw_type_t enumeration, while the instance id
 * uniquely identifies the sharing instance from among others of the same
 * hardware sharing type.
 *
 * The physical PGs are organized into an overall hierarchy, and are tracked
 * in a number of different per CPU, and per pghw_type_t type groups.
 * As an example:
 *
 * -------------
 * | pg_hw     |
 * | (group_t) |
 * -------------
 *  ||                          ============================
 *  ||\\-----------------------//       \\                 \\
 *  ||  | hwset (PGC_HW_CHIP) |        -------------      -------------
 *  ||  | (group_t)           |        | pghw_t    |      | pghw_t    |
 *  ||  -----------------------        | chip 0    |      | chip 1    |
 *  ||                                 -------------      -------------
 *  ||                                 \\  \\  \\  \\     \\  \\  \\  \\
 *  ||                                  cpu cpu cpu cpu    cpu cpu cpu cpu
 *  ||
 *  ||                          ============================
 *  ||\\-----------------------//       \\                 \\
 *  ||  | hwset (PGC_HW_IPIPE)|        -------------      -------------
 *  ||  | (group_t)           |        | pghw_t    |      | pghw_t    |
 *  ||  -----------------------        | ipipe 0   |      | ipipe 1   |
 *  ||                                 -------------      -------------
 *  ||                                 \\  \\             \\  \\
 *  ||                                  cpu cpu            cpu cpu
 *  ...
 *
 *
 * The top level pg_hw is a group of "hwset" groups. Each hwset holds of group
 * of physical PGs of the same hardware sharing type. Within each hwset, the
 * PG's instance id uniquely identifies the grouping relationshsip among other
 * groupings of the same sharing type. The instance id for a grouping is
 * platform defined, and in some cases may be used by platform code as a handle
 * to search for a particular relationship instance.
 *
 * Each physical PG (by virtue of the embedded pg_t) contains a group of CPUs
 * that participate in the sharing relationship. Each CPU also has associated
 * with it a grouping tracking the PGs in which the CPU belongs. This can be
 * used to iterate over the various relationships in which the CPU participates
 * (the CPU's chip, cache, lgroup, etc.).
 *
 * The hwsets are created dynamically as new hardware sharing relationship types
 * are instantiated. They are never destroyed, as once a given relationship
 * type appears in the system, it is quite likely that at least one instance of
 * that relationship will always persist as long as the system is running.
 */

static group_t          *pg_hw;         /* top level pg hw group */

/*
 * Physical PG kstats
 */
struct pghw_kstat {
        kstat_named_t   pg_id;
        kstat_named_t   pg_class;
        kstat_named_t   pg_ncpus;
        kstat_named_t   pg_instance_id;
        kstat_named_t   pg_hw;
        kstat_named_t   pg_policy;
} pghw_kstat = {
        { "id",                 KSTAT_DATA_INT32 },
        { "pg_class",           KSTAT_DATA_STRING },
        { "ncpus",              KSTAT_DATA_UINT32 },
        { "instance_id",        KSTAT_DATA_UINT32 },
        { "hardware",           KSTAT_DATA_STRING },
        { "policy",             KSTAT_DATA_STRING },
};

kmutex_t                pghw_kstat_lock;

/*
 * Capacity and Utilization PG kstats
 *
 * These kstats are updated one at a time, so we can have a single scratch space
 * to fill the data.
 *
 * kstat fields:
 *
 *   pg_id              PG ID for PG described by this kstat
 *
 *   pg_parent          Parent PG ID. The value -1 means "no parent".
 *
 *   pg_ncpus           Number of CPUs within this PG
 *
 *   pg_cpus            String describing CPUs within this PG
 *
 *   pg_relationship    Name of sharing relationship for this PG
 *
 *   pg_generation      Generation value that increases whenever any CPU leaves
 *                        or joins PG. Two kstat snapshots for the same
 *                        CPU may only be compared if they have the same
 *                        generation
 *
 *   pg_hw_util         Running value of PG utilization for the sharing
 *                        relationship
 *
 *   pg_hw_util_time_running
 *                      Total time spent collecting CU data. The time may be
 *                      less than wall time if CU counters were stopped for
 *                      some time.
 *
 *   pg_hw_util_time_stopped Total time the CU counters were stopped.
 *
 *   pg_hw_util_rate    Utilization rate, expressed in operations per second.
 *
 *   pg_hw_util_rate_max Maximum observed value of utilization rate.
 */
struct pghw_cu_kstat {
        kstat_named_t   pg_id;
        kstat_named_t   pg_parent_id;
        kstat_named_t   pg_ncpus;
        kstat_named_t   pg_generation;
        kstat_named_t   pg_hw_util;
        kstat_named_t   pg_hw_util_time_running;
        kstat_named_t   pg_hw_util_time_stopped;
        kstat_named_t   pg_hw_util_rate;
        kstat_named_t   pg_hw_util_rate_max;
        kstat_named_t   pg_cpus;
        kstat_named_t   pg_relationship;
} pghw_cu_kstat = {
        { "pg_id",              KSTAT_DATA_INT32 },
        { "parent_pg_id",       KSTAT_DATA_INT32 },
        { "ncpus",              KSTAT_DATA_UINT32 },
        { "generation",         KSTAT_DATA_UINT32   },
        { "hw_util",            KSTAT_DATA_UINT64   },
        { "hw_util_time_running",       KSTAT_DATA_UINT64   },
        { "hw_util_time_stopped",       KSTAT_DATA_UINT64   },
        { "hw_util_rate",       KSTAT_DATA_UINT64   },
        { "hw_util_rate_max",   KSTAT_DATA_UINT64   },
        { "cpus",               KSTAT_DATA_STRING   },
        { "relationship",       KSTAT_DATA_STRING   },
};

/*
 * Calculate the string size to represent NCPUS. Allow 5 digits for each CPU ID
 * plus one space per CPU plus NUL byte in the end. This is only an estimate,
 * since we try to compress CPU ranges as x-y. In the worst case the string
 * representation of CPUs may be truncated.
 */
#define CPUSTR_LEN(ncpus) ((ncpus) * 6)

/*
 * Maximum length of the string that represents list of CPUs
 */
static int pg_cpulist_maxlen = 0;

static void             pghw_kstat_create(pghw_t *);
static int              pghw_kstat_update(kstat_t *, int);
static int              pghw_cu_kstat_update(kstat_t *, int);
static int              cpu2id(void *);

/*
 * hwset operations
 */
static group_t          *pghw_set_create(pghw_type_t);
static void             pghw_set_add(group_t *, pghw_t *);
static void             pghw_set_remove(group_t *, pghw_t *);

static void             pghw_cpulist_alloc(pghw_t *);
static int              cpu2id(void *);
static pgid_t           pghw_parent_id(pghw_t *);

/*
 * Initialize the physical portion of a hardware PG
 */
void
pghw_init(pghw_t *pg, cpu_t *cp, pghw_type_t hw)
{
        group_t         *hwset;

        if ((hwset = pghw_set_lookup(hw)) == NULL) {
                /*
                 * Haven't seen this hardware type yet
                 */
                hwset = pghw_set_create(hw);
        }

        pghw_set_add(hwset, pg);
        pg->pghw_hw = hw;
        pg->pghw_generation = 0;
        pg->pghw_instance =
            pg_plat_hw_instance_id(cp, hw);
        pghw_kstat_create(pg);

        /*
         * Hardware sharing relationship specific initialization
         */
        switch (pg->pghw_hw) {
        case PGHW_POW_ACTIVE:
                pg->pghw_handle =
                    (pghw_handle_t)cpupm_domain_init(cp, CPUPM_DTYPE_ACTIVE);
                break;
        case PGHW_POW_IDLE:
                pg->pghw_handle =
                    (pghw_handle_t)cpupm_domain_init(cp, CPUPM_DTYPE_IDLE);
                break;
        default:
                pg->pghw_handle = (pghw_handle_t)NULL;
        }
}

/*
 * Teardown the physical portion of a physical PG
 */
void
pghw_fini(pghw_t *pg)
{
        group_t         *hwset;

        pghw_cmt_fini(pg);

        hwset = pghw_set_lookup(pg->pghw_hw);
        ASSERT(hwset != NULL);

        pghw_set_remove(hwset, pg);
        pg->pghw_instance = (id_t)PGHW_INSTANCE_ANON;
        pg->pghw_hw = (pghw_type_t)-1;

        if (pg->pghw_kstat != NULL)
                kstat_delete(pg->pghw_kstat);

}

/*
 * PG is removed from CMT hierarchy
 */
void
pghw_cmt_fini(pghw_t *pg)
{
        /*
         * Destroy string representation of CPUs
         */
        if (pg->pghw_cpulist != NULL) {
                kmem_free(pg->pghw_cpulist,
                    pg->pghw_cpulist_len);
                pg->pghw_cpulist = NULL;
        }

        /*
         * Destroy CU kstats
         */
        if (pg->pghw_cu_kstat != NULL) {
                kstat_delete(pg->pghw_cu_kstat);
                pg->pghw_cu_kstat = NULL;
        }
}

/*
 * Find an existing physical PG in which to place
 * the given CPU for the specified hardware sharing
 * relationship
 */
pghw_t *
pghw_place_cpu(cpu_t *cp, pghw_type_t hw)
{
        group_t         *hwset;

        if ((hwset = pghw_set_lookup(hw)) == NULL) {
                return (NULL);
        }

        return ((pghw_t *)pg_cpu_find_pg(cp, hwset));
}

/*
 * Find the pg representing the hw sharing relationship in which
 * cp belongs
 */
pghw_t *
pghw_find_pg(cpu_t *cp, pghw_type_t hw)
{
        group_iter_t    i;
        pghw_t  *pg;

        group_iter_init(&i);
        while ((pg = group_iterate(&cp->cpu_pg->pgs, &i)) != NULL) {
                if (pg->pghw_hw == hw)
                        return (pg);
        }
        return (NULL);
}

/*
 * Find the PG of the given hardware sharing relationship
 * type with the given instance id
 */
pghw_t *
pghw_find_by_instance(id_t id, pghw_type_t hw)
{
        group_iter_t    i;
        group_t         *set;
        pghw_t          *pg;

        set = pghw_set_lookup(hw);
        if (!set)
                return (NULL);

        group_iter_init(&i);
        while ((pg = group_iterate(set, &i)) != NULL) {
                if (pg->pghw_instance == id)
                        return (pg);
        }
        return (NULL);
}

/*
 * CPUs physical ID cache creation / destruction
 * The cache's elements are initialized to the CPU's id
 */
void
pghw_physid_create(cpu_t *cp)
{
        int     i;

        cp->cpu_physid = kmem_alloc(sizeof (cpu_physid_t), KM_SLEEP);

        for (i = 0; i < (sizeof (cpu_physid_t) / sizeof (id_t)); i++) {
                ((id_t *)cp->cpu_physid)[i] = cp->cpu_id;
        }
}

void
pghw_physid_destroy(cpu_t *cp)
{
        if (cp->cpu_physid) {
                kmem_free(cp->cpu_physid, sizeof (cpu_physid_t));
                cp->cpu_physid = NULL;
        }
}

/*
 * Create a new, empty hwset.
 * This routine may block, and must not be called from any
 * paused CPU context.
 */
static group_t  *
pghw_set_create(pghw_type_t hw)
{
        group_t *g;
        int     ret;

        /*
         * Create the top level PG hw group if it doesn't already exist
         * This is a "set" of hardware sets, that is ordered (and indexed)
         * by the pghw_type_t enum.
         */
        if (pg_hw == NULL) {
                pg_hw = kmem_alloc(sizeof (group_t), KM_SLEEP);
                group_create(pg_hw);
                group_expand(pg_hw, (uint_t)PGHW_NUM_COMPONENTS);
        }

        /*
         * Create the new hwset
         * Add it to the top level pg_hw group.
         */
        g = kmem_alloc(sizeof (group_t), KM_SLEEP);
        group_create(g);

        ret = group_add_at(pg_hw, g, (uint_t)hw);
        ASSERT(ret == 0);

        return (g);
}

/*
 * Find the hwset associated with the given hardware sharing type
 */
group_t *
pghw_set_lookup(pghw_type_t hw)
{
        group_t *hwset;

        if (pg_hw == NULL)
                return (NULL);

        hwset = GROUP_ACCESS(pg_hw, (uint_t)hw);
        return (hwset);
}

/*
 * Add a PG to a hwset
 */
static void
pghw_set_add(group_t *hwset, pghw_t *pg)
{
        (void) group_add(hwset, pg, GRP_RESIZE);
}

/*
 * Remove a PG from a hwset
 */
static void
pghw_set_remove(group_t *hwset, pghw_t *pg)
{
        int result;

        result = group_remove(hwset, pg, GRP_RESIZE);
        ASSERT(result == 0);
}

/*
 * Return a string name given a pg_hw sharing type
 */
char *
pghw_type_string(pghw_type_t hw)
{
        switch (hw) {
        case PGHW_IPIPE:
                return ("Integer Pipeline");
        case PGHW_CACHE:
                return ("Cache");
        case PGHW_FPU:
                return ("Floating Point Unit");
        case PGHW_MPIPE:
                return ("Data Pipe to memory");
        case PGHW_CHIP:
                return ("Socket");
        case PGHW_MEMORY:
                return ("Memory");
        case PGHW_POW_ACTIVE:
                return ("CPU PM Active Power Domain");
        case PGHW_POW_IDLE:
                return ("CPU PM Idle Power Domain");
        default:
                return ("unknown");
        }
}

/*
 * Create / Update routines for PG hw kstats
 *
 * It is the intention of these kstats to provide some level
 * of informational / debugging observability into the types
 * and nature of the system's detected hardware sharing relationships
 */
void
pghw_kstat_create(pghw_t *pg)
{
        char *sharing = pghw_type_string(pg->pghw_hw);
        char name[KSTAT_STRLEN + 1];

        /*
         * Canonify PG name to conform to kstat name rules
         */
        (void) strncpy(name, pghw_type_string(pg->pghw_hw), KSTAT_STRLEN + 1);
        strident_canon(name, KSTAT_STRLEN + 1);

        /*
         * Create a hardware performance kstat
         */
        if ((pg->pghw_kstat = kstat_create("pg", ((pg_t *)pg)->pg_id,
            "pg", "pg",
            KSTAT_TYPE_NAMED,
            sizeof (pghw_kstat) / sizeof (kstat_named_t),
            KSTAT_FLAG_VIRTUAL)) != NULL) {
                /* Class string, hw string, and policy string */
                pg->pghw_kstat->ks_data_size += PG_CLASS_NAME_MAX;
                pg->pghw_kstat->ks_data_size += PGHW_KSTAT_STR_LEN_MAX;
                pg->pghw_kstat->ks_data_size += PGHW_KSTAT_STR_LEN_MAX;
                pg->pghw_kstat->ks_lock = &pghw_kstat_lock;
                pg->pghw_kstat->ks_data = &pghw_kstat;
                pg->pghw_kstat->ks_update = pghw_kstat_update;
                pg->pghw_kstat->ks_private = pg;
                kstat_install(pg->pghw_kstat);
        }

        if (pg_cpulist_maxlen == 0)
                pg_cpulist_maxlen = CPUSTR_LEN(max_ncpus);

        /*
         * Create a physical pg kstat
         */
        if ((pg->pghw_cu_kstat = kstat_create("pg_hw_perf", ((pg_t *)pg)->pg_id,
            name, "processor_group",
            KSTAT_TYPE_NAMED,
            sizeof (pghw_cu_kstat) / sizeof (kstat_named_t),
            KSTAT_FLAG_VIRTUAL)) != NULL) {
                pg->pghw_cu_kstat->ks_lock = &pghw_kstat_lock;
                pg->pghw_cu_kstat->ks_data = &pghw_cu_kstat;
                pg->pghw_cu_kstat->ks_update = pghw_cu_kstat_update;
                pg->pghw_cu_kstat->ks_private = pg;
                pg->pghw_cu_kstat->ks_data_size += strlen(sharing) + 1;
                /* Allow space for CPU strings */
                pg->pghw_cu_kstat->ks_data_size += PGHW_KSTAT_STR_LEN_MAX;
                pg->pghw_cu_kstat->ks_data_size += pg_cpulist_maxlen;
                kstat_install(pg->pghw_cu_kstat);
        }
}

int
pghw_kstat_update(kstat_t *ksp, int rw)
{
        struct pghw_kstat       *pgsp = &pghw_kstat;
        pghw_t                  *pg = ksp->ks_private;

        if (rw == KSTAT_WRITE)
                return (EACCES);

        pgsp->pg_id.value.ui32 = ((pg_t *)pg)->pg_id;
        pgsp->pg_ncpus.value.ui32 = GROUP_SIZE(&((pg_t *)pg)->pg_cpus);
        pgsp->pg_instance_id.value.ui32 = pg->pghw_instance;
        kstat_named_setstr(&pgsp->pg_class, ((pg_t *)pg)->pg_class->pgc_name);
        kstat_named_setstr(&pgsp->pg_hw, pghw_type_string(pg->pghw_hw));
        kstat_named_setstr(&pgsp->pg_policy, pg_policy_name((pg_t *)pg));
        return (0);
}

int
pghw_cu_kstat_update(kstat_t *ksp, int rw)
{
        struct pghw_cu_kstat    *pgsp = &pghw_cu_kstat;
        pghw_t                  *pg = ksp->ks_private;
        pghw_util_t             *hw_util = &pg->pghw_stats;
        boolean_t               has_cpc_privilege;

        if (rw == KSTAT_WRITE)
                return (EACCES);

        /*
         * Check whether the caller has priv_cpc_cpu privilege. If it doesn't,
         * it will not get hardware utilization data.
         */

        has_cpc_privilege = (secpolicy_cpc_cpu(crgetcred()) == 0);

        pgsp->pg_id.value.i32 = ((pg_t *)pg)->pg_id;
        pgsp->pg_parent_id.value.i32 = (int)pghw_parent_id(pg);

        pgsp->pg_ncpus.value.ui32 = GROUP_SIZE(&((pg_t *)pg)->pg_cpus);

        /*
         * Allocate memory for the string representing the list of CPUs in PG.
         * This memory should persist past the call to pghw_cu_kstat_update()
         * since the kstat snapshot routine will reference this memory.
         */
        pghw_cpulist_alloc(pg);

        if (pg->pghw_kstat_gen != pg->pghw_generation) {
                /*
                 * PG kstat generation number is out of sync with PG's
                 * generation mumber. It means that some CPUs could have joined
                 * or left PG and it is not possible to compare the numbers
                 * obtained before and after the generation change.
                 *
                 * Reset the maximum utilization rate and start computing it
                 * from scratch.
                 */
                hw_util->pghw_util = 0;
                hw_util->pghw_rate_max = 0;
                pg->pghw_kstat_gen = pg->pghw_generation;
        }

        /*
         * We can't block on CPU lock because when PG is destroyed (under
         * cpu_lock) it tries to delete this kstat and it will wait for us to
         * complete which will never happen since we are waiting for cpu_lock to
         * drop. Deadlocks are fun!
         */
        if (mutex_tryenter(&cpu_lock)) {
                if (pg->pghw_cpulist != NULL &&
                    *(pg->pghw_cpulist) == '\0') {
                        (void) group2intlist(&(((pg_t *)pg)->pg_cpus),
                            pg->pghw_cpulist, pg->pghw_cpulist_len, cpu2id);
                }

                if (has_cpc_privilege)
                        cu_pg_update(pg);

                mutex_exit(&cpu_lock);
        }

        pgsp->pg_generation.value.ui32 = pg->pghw_kstat_gen;
        if (pg->pghw_cpulist != NULL)
                kstat_named_setstr(&pgsp->pg_cpus, pg->pghw_cpulist);
        else
                kstat_named_setstr(&pgsp->pg_cpus, "");

        kstat_named_setstr(&pgsp->pg_relationship,
            pghw_type_string(pg->pghw_hw));

        if (has_cpc_privilege) {
                pgsp->pg_hw_util.value.ui64 = hw_util->pghw_util;
                pgsp->pg_hw_util_time_running.value.ui64 =
                    hw_util->pghw_time_running;
                pgsp->pg_hw_util_time_stopped.value.ui64 =
                    hw_util->pghw_time_stopped;
                pgsp->pg_hw_util_rate.value.ui64 = hw_util->pghw_rate;
                pgsp->pg_hw_util_rate_max.value.ui64 = hw_util->pghw_rate_max;
        } else {
                pgsp->pg_hw_util.value.ui64 = 0;
                pgsp->pg_hw_util_time_running.value.ui64 = 0;
                pgsp->pg_hw_util_time_stopped.value.ui64 = 0;
                pgsp->pg_hw_util_rate.value.ui64 = 0;
                pgsp->pg_hw_util_rate_max.value.ui64 = 0;
        }

        return (0);
}

/*
 * Update the string representation of CPUs in PG (pg->pghw_cpulist).
 * The string representation is used for kstats.
 *
 * The string is allocated if it has not already been or if it is already
 * allocated and PG has more CPUs now. If PG has smaller or equal number of
 * CPUs, but the actual CPUs may have changed, the string is reset to the empty
 * string causes the string representation to be recreated. The pghw_generation
 * field is used to detect whether CPUs within the pg may have changed.
 */
static void
pghw_cpulist_alloc(pghw_t *pg)
{
        uint_t  ncpus = GROUP_SIZE(&((pg_t *)pg)->pg_cpus);
        size_t  len = CPUSTR_LEN(ncpus);

        /*
         * If the pghw_cpulist string is already allocated we need to make sure
         * that it has sufficient length. Also if the set of CPUs may have
         * changed, we need to re-generate the string.
         */
        if (pg->pghw_cpulist != NULL &&
            pg->pghw_kstat_gen != pg->pghw_generation) {
                if (len <= pg->pghw_cpulist_len) {
                        /*
                         * There is sufficient space in the pghw_cpulist for
                         * the new set of CPUs. Just clear the string to trigger
                         * re-generation of list of CPUs
                         */
                        *(pg->pghw_cpulist) = '\0';
                } else {
                        /*
                         * There is, potentially, insufficient space in
                         * pghw_cpulist, so reallocate the string.
                         */
                        ASSERT(strlen(pg->pghw_cpulist) < pg->pghw_cpulist_len);
                        kmem_free(pg->pghw_cpulist, pg->pghw_cpulist_len);
                        pg->pghw_cpulist = NULL;
                        pg->pghw_cpulist_len = 0;
                }
        }

        if (pg->pghw_cpulist == NULL) {
                /*
                 * Allocate space to hold cpulist.
                 *
                 * Length can not be bigger that the maximum space we have
                 * allowed for the kstat buffer
                 */
                if (len > pg_cpulist_maxlen)
                        len = pg_cpulist_maxlen;
                if (len > 0) {
                        pg->pghw_cpulist = kmem_zalloc(len, KM_NOSLEEP);
                        if (pg->pghw_cpulist != NULL)
                                pg->pghw_cpulist_len = len;
                }
        }
}

static int
cpu2id(void *v)
{
        cpu_t *cp = (cpu_t *)v;

        ASSERT(v != NULL);

        return (cp->cpu_id);
}

/*
 * Return parent ID or -1 if there is no parent.
 * All hardware PGs are currently also CMT PGs, but for safety we check the
 * class matches cmt before we upcast the pghw pointer to pg_cmt_t.
 */
static pgid_t
pghw_parent_id(pghw_t *pghw)
{
        pg_t *pg = (pg_t *)pghw;
        pgid_t parent_id = -1;

        if (pg != NULL && strcmp(pg->pg_class->pgc_name, "cmt") == 0) {
                pg_cmt_t *cmt = (pg_cmt_t *)pg;
                pg_t *parent = (pg_t *)cmt->cmt_parent;
                if (parent != NULL)
                        parent_id = parent->pg_id;
        }

        return (parent_id);
}