linux_kernel/arch/x86/kernel/cpu/intel_rdt.c

/*
 * 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>
 *    Vikas Shivappa <vikas.shivappa@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * 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/slab.h>
#include <linux/err.h>
#include <linux/cacheinfo.h>
#include <linux/cpuhotplug.h>

#include <asm/intel-family.h>
#include <asm/intel_rdt.h>

/* Mutex to protect rdtgroup access. */
DEFINE_MUTEX(rdtgroup_mutex);

DEFINE_PER_CPU_READ_MOSTLY(int, cpu_closid);

#define domain_init(id) LIST_HEAD_INIT(rdt_resources_all[id].domains)

struct rdt_resource rdt_resources_all[] = {
	{
		.name		= "L3",
		.domains	= domain_init(RDT_RESOURCE_L3),
		.msr_base	= IA32_L3_CBM_BASE,
		.min_cbm_bits	= 1,
		.cache_level	= 3,
		.cbm_idx_multi	= 1,
		.cbm_idx_offset	= 0
	},
	{
		.name		= "L3DATA",
		.domains	= domain_init(RDT_RESOURCE_L3DATA),
		.msr_base	= IA32_L3_CBM_BASE,
		.min_cbm_bits	= 1,
		.cache_level	= 3,
		.cbm_idx_multi	= 2,
		.cbm_idx_offset	= 0
	},
	{
		.name		= "L3CODE",
		.domains	= domain_init(RDT_RESOURCE_L3CODE),
		.msr_base	= IA32_L3_CBM_BASE,
		.min_cbm_bits	= 1,
		.cache_level	= 3,
		.cbm_idx_multi	= 2,
		.cbm_idx_offset	= 1
	},
	{
		.name		= "L2",
		.domains	= domain_init(RDT_RESOURCE_L2),
		.msr_base	= IA32_L2_CBM_BASE,
		.min_cbm_bits	= 1,
		.cache_level	= 2,
		.cbm_idx_multi	= 1,
		.cbm_idx_offset	= 0
	},
};

static int cbm_idx(struct rdt_resource *r, int closid)
{
	return closid * r->cbm_idx_multi + r->cbm_idx_offset;
}

/*
 * cache_alloc_hsw_probe() - Have to probe for Intel haswell server CPUs
 * as they do not have CPUID enumeration support for Cache allocation.
 * The check for Vendor/Family/Model is not enough to guarantee that
 * the MSRs won't #GP fault because only the following SKUs support
 * CAT:
 *	Intel(R) Xeon(R)  CPU E5-2658  v3  @  2.20GHz
 *	Intel(R) Xeon(R)  CPU E5-2648L v3  @  1.80GHz
 *	Intel(R) Xeon(R)  CPU E5-2628L v3  @  2.00GHz
 *	Intel(R) Xeon(R)  CPU E5-2618L v3  @  2.30GHz
 *	Intel(R) Xeon(R)  CPU E5-2608L v3  @  2.00GHz
 *	Intel(R) Xeon(R)  CPU E5-2658A v3  @  2.20GHz
 *
 * Probe by trying to write the first of the L3 cach mask registers
 * and checking that the bits stick. Max CLOSids is always 4 and max cbm length
 * is always 20 on hsw server parts. The minimum cache bitmask length
 * allowed for HSW server is always 2 bits. Hardcode all of them.
 */
static inline bool cache_alloc_hsw_probe(void)
{
	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
	    boot_cpu_data.x86 == 6 &&
	    boot_cpu_data.x86_model == INTEL_FAM6_HASWELL_X) {
		struct rdt_resource *r  = &rdt_resources_all[RDT_RESOURCE_L3];
		u32 l, h, max_cbm = BIT_MASK(20) - 1;

		if (wrmsr_safe(IA32_L3_CBM_BASE, max_cbm, 0))
			return false;
		rdmsr(IA32_L3_CBM_BASE, l, h);

		/* If all the bits were set in MSR, return success */
		if (l != max_cbm)
			return false;

		r->num_closid = 4;
		r->cbm_len = 20;
		r->max_cbm = max_cbm;
		r->min_cbm_bits = 2;
		r->capable = true;
		r->enabled = true;

		return true;
	}

	return false;
}

static void rdt_get_config(int idx, struct rdt_resource *r)
{
	union cpuid_0x10_1_eax eax;
	union cpuid_0x10_1_edx edx;
	u32 ebx, ecx;

	cpuid_count(0x00000010, idx, &eax.full, &ebx, &ecx, &edx.full);
	r->num_closid = edx.split.cos_max + 1;
	r->cbm_len = eax.split.cbm_len + 1;
	r->max_cbm = BIT_MASK(eax.split.cbm_len + 1) - 1;
	r->capable = true;
	r->enabled = true;
}

static void rdt_get_cdp_l3_config(int type)
{
	struct rdt_resource *r_l3 = &rdt_resources_all[RDT_RESOURCE_L3];
	struct rdt_resource *r = &rdt_resources_all[type];

	r->num_closid = r_l3->num_closid / 2;
	r->cbm_len = r_l3->cbm_len;
	r->max_cbm = r_l3->max_cbm;
	r->capable = true;
	/*
	 * By default, CDP is disabled. CDP can be enabled by mount parameter
	 * "cdp" during resctrl file system mount time.
	 */
	r->enabled = false;
}

static inline bool get_rdt_resources(void)
{
	bool ret = false;

	if (cache_alloc_hsw_probe())
		return true;

	if (!boot_cpu_has(X86_FEATURE_RDT_A))
		return false;

	if (boot_cpu_has(X86_FEATURE_CAT_L3)) {
		rdt_get_config(1, &rdt_resources_all[RDT_RESOURCE_L3]);
		if (boot_cpu_has(X86_FEATURE_CDP_L3)) {
			rdt_get_cdp_l3_config(RDT_RESOURCE_L3DATA);
			rdt_get_cdp_l3_config(RDT_RESOURCE_L3CODE);
		}
		ret = true;
	}
	if (boot_cpu_has(X86_FEATURE_CAT_L2)) {
		/* CPUID 0x10.2 fields are same format at 0x10.1 */
		rdt_get_config(2, &rdt_resources_all[RDT_RESOURCE_L2]);
		ret = true;
	}

	return ret;
}

static int get_cache_id(int cpu, int level)
{
	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
	int i;

	for (i = 0; i < ci->num_leaves; i++) {
		if (ci->info_list[i].level == level)
			return ci->info_list[i].id;
	}

	return -1;
}

void rdt_cbm_update(void *arg)
{
	struct msr_param *m = (struct msr_param *)arg;
	struct rdt_resource *r = m->res;
	int i, cpu = smp_processor_id();
	struct rdt_domain *d;

	list_for_each_entry(d, &r->domains, list) {
		/* Find the domain that contains this CPU */
		if (cpumask_test_cpu(cpu, &d->cpu_mask))
			goto found;
	}
	pr_info_once("cpu %d not found in any domain for resource %s\n",
		     cpu, r->name);

	return;

found:
	for (i = m->low; i < m->high; i++) {
		int idx = cbm_idx(r, i);

		wrmsrl(r->msr_base + idx, d->cbm[i]);
	}
}

/*
 * rdt_find_domain - Find a domain in a resource that matches input resource id
 *
 * Search resource r's domain list to find the resource id. If the resource
 * id is found in a domain, return the domain. Otherwise, if requested by
 * caller, return the first domain whose id is bigger than the input id.
 * The domain list is sorted by id in ascending order.
 */
static struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
					  struct list_head **pos)
{
	struct rdt_domain *d;
	struct list_head *l;

	if (id < 0)
		return ERR_PTR(id);

	list_for_each(l, &r->domains) {
		d = list_entry(l, struct rdt_domain, 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;
}

/*
 * domain_add_cpu - Add a cpu to a resource's domain list.
 *
 * If an existing domain in the resource r's domain list matches the cpu's
 * resource id, add the cpu in the domain.
 *
 * Otherwise, a new domain is allocated and inserted into the right position
 * in the domain list sorted by id in ascending order.
 *
 * The order in the domain list is visible to users when we print entries
 * in the schemata file and schemata input is validated to have the same order
 * as this list.
 */
static void domain_add_cpu(int cpu, struct rdt_resource *r)
{
	int i, id = get_cache_id(cpu, r->cache_level);
	struct list_head *add_pos = NULL;
	struct rdt_domain *d;

	d = rdt_find_domain(r, id, &add_pos);
	if (IS_ERR(d)) {
		pr_warn("Could't find cache id for cpu %d\n", cpu);
		return;
	}

	if (d) {
		cpumask_set_cpu(cpu, &d->cpu_mask);
		return;
	}

	d = kzalloc_node(sizeof(*d), GFP_KERNEL, cpu_to_node(cpu));
	if (!d)
		return;

	d->id = id;

	d->cbm = kmalloc_array(r->num_closid, sizeof(*d->cbm), GFP_KERNEL);
	if (!d->cbm) {
		kfree(d);
		return;
	}

	for (i = 0; i < r->num_closid; i++) {
		int idx = cbm_idx(r, i);

		d->cbm[i] = r->max_cbm;
		wrmsrl(r->msr_base + idx, d->cbm[i]);
	}

	cpumask_set_cpu(cpu, &d->cpu_mask);
	list_add_tail(&d->list, add_pos);
	r->num_domains++;
}

static void domain_remove_cpu(int cpu, struct rdt_resource *r)
{
	int id = get_cache_id(cpu, r->cache_level);
	struct rdt_domain *d;

	d = rdt_find_domain(r, id, NULL);
	if (IS_ERR_OR_NULL(d)) {
		pr_warn("Could't find cache id for cpu %d\n", cpu);
		return;
	}

	cpumask_clear_cpu(cpu, &d->cpu_mask);
	if (cpumask_empty(&d->cpu_mask)) {
		r->num_domains--;
		kfree(d->cbm);
		list_del(&d->list);
		kfree(d);
	}
}

static void clear_closid(int cpu)
{
	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);

	per_cpu(cpu_closid, cpu) = 0;
	state->closid = 0;
	wrmsr(MSR_IA32_PQR_ASSOC, state->rmid, 0);
}

static int intel_rdt_online_cpu(unsigned int cpu)
{
	struct rdt_resource *r;

	mutex_lock(&rdtgroup_mutex);
	for_each_capable_rdt_resource(r)
		domain_add_cpu(cpu, r);
	/* The cpu is set in default rdtgroup after online. */
	cpumask_set_cpu(cpu, &rdtgroup_default.cpu_mask);
	clear_closid(cpu);
	mutex_unlock(&rdtgroup_mutex);

	return 0;
}

static int intel_rdt_offline_cpu(unsigned int cpu)
{
	struct rdtgroup *rdtgrp;
	struct rdt_resource *r;

	mutex_lock(&rdtgroup_mutex);
	for_each_capable_rdt_resource(r)
		domain_remove_cpu(cpu, r);
	list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
		if (cpumask_test_and_clear_cpu(cpu, &rdtgrp->cpu_mask))
			break;
	}
	clear_closid(cpu);
	mutex_unlock(&rdtgroup_mutex);

	return 0;
}

static int __init intel_rdt_late_init(void)
{
	struct rdt_resource *r;
	int state, ret;

	if (!get_rdt_resources())
		return -ENODEV;

	state = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
				  "x86/rdt/cat:online:",
				  intel_rdt_online_cpu, intel_rdt_offline_cpu);
	if (state < 0)
		return state;

	ret = rdtgroup_init();
	if (ret) {
		cpuhp_remove_state(state);
		return ret;
	}

	for_each_capable_rdt_resource(r)
		pr_info("Intel RDT %s allocation detected\n", r->name);

	return 0;
}

late_initcall(intel_rdt_late_init);