Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5ff193fb authored by Fenghua Yu's avatar Fenghua Yu Committed by Thomas Gleixner
Browse files

x86/intel_rdt: Add basic resctrl filesystem support 



Use kernfs as basis for our user interface filesystem. This patch
supports mount/umount, and one mount parameter "cdp" to enable code/data
prioritization (though all we do at this point is ensure that the system
can support CDP).  The file system is not populated yet in this patch.

[ tglx: Fixed up a few nits and added cdp handling in case of error ]

Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Shaohua Li" <shli@fb.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Stephane Eranian" <eranian@google.com>
Cc: "Dave Hansen" <dave.hansen@intel.com>
Cc: "David Carrillo-Cisneros" <davidcc@google.com>
Cc: "Nilay Vaish" <nilayvaish@gmail.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "Borislav Petkov" <bp@suse.de>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1477692289-37412-4-git-send-email-fenghua.yu@intel.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 2264d9c7

arch/x86/include/asm/intel_rdt.h

+26 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_INTEL_RDT_H

#define _ASM_X86_INTEL_RDT_H



#include <linux/jump_label.h>



#define IA32_L3_QOS_CFG		0xc81

#define IA32_L3_CBM_BASE	0xc90

#define IA32_L2_CBM_BASE	0xd10



#define L3_QOS_CDP_ENABLE	0x01ULL



/**

 * struct rdtgroup - store rdtgroup's data in resctrl file system.

 * @kn:				kernfs node

 * @rdtgroup_list:		linked list for all rdtgroups

 * @closid:			closid for this rdtgroup

 */

struct rdtgroup {

	struct kernfs_node	*kn;

	struct list_head	rdtgroup_list;

	int			closid;

};



/* List of all resource groups */

extern struct list_head rdt_all_groups;



int __init rdtgroup_init(void);



/**

 * struct rdt_resource - attributes of an RDT resource

 * @enabled:			Is this feature enabled on this machine
@@ -68,6 +90,10 @@ struct msr_param { 
extern struct mutex rdtgroup_mutex;



extern struct rdt_resource rdt_resources_all[];

extern struct rdtgroup rdtgroup_default;

DECLARE_STATIC_KEY_FALSE(rdt_enable_key);



int __init rdtgroup_init(void);



enum {

	RDT_RESOURCE_L3,

arch/x86/kernel/cpu/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ obj-$(CONFIG_CPU_SUP_CENTAUR) += centaur.o 
obj-$(CONFIG_CPU_SUP_TRANSMETA_32)	+= transmeta.o

obj-$(CONFIG_CPU_SUP_UMC_32)		+= umc.o



obj-$(CONFIG_INTEL_RDT_A)	+= intel_rdt.o

obj-$(CONFIG_INTEL_RDT_A)	+= intel_rdt.o intel_rdt_rdtgroup.o



obj-$(CONFIG_X86_MCE)			+= mcheck/

obj-$(CONFIG_MTRR)			+= mtrr/

arch/x86/kernel/cpu/intel_rdt.c

+7 −1
Original line number Diff line number Diff line
@@ -361,7 +361,7 @@ static int intel_rdt_offline_cpu(unsigned int cpu) 
static int __init intel_rdt_late_init(void)

{

	struct rdt_resource *r;

	int state;

	int state, ret;



	if (!get_rdt_resources())

		return -ENODEV;
@@ -372,6 +372,12 @@ static int __init intel_rdt_late_init(void) 
	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);

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

0 → 100644
+271 −0
Original line number Diff line number Diff line 
/*

 * User interface for Resource Alloction in Resource Director Technology(RDT)

 *

 * Copyright (C) 2016 Intel Corporation

 *

 * Author: Fenghua Yu <fenghua.yu@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.

 */



#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt



#include <linux/fs.h>

#include <linux/sysfs.h>

#include <linux/kernfs.h>

#include <linux/slab.h>



#include <uapi/linux/magic.h>



#include <asm/intel_rdt.h>



DEFINE_STATIC_KEY_FALSE(rdt_enable_key);

struct kernfs_root *rdt_root;

struct rdtgroup rdtgroup_default;

LIST_HEAD(rdt_all_groups);



static void l3_qos_cfg_update(void *arg)

{

	bool *enable = arg;



	wrmsrl(IA32_L3_QOS_CFG, *enable ? L3_QOS_CDP_ENABLE : 0ULL);

}



static int set_l3_qos_cfg(struct rdt_resource *r, bool enable)

{

	cpumask_var_t cpu_mask;

	struct rdt_domain *d;

	int cpu;



	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))

		return -ENOMEM;



	list_for_each_entry(d, &r->domains, list) {

		/* Pick one CPU from each domain instance to update MSR */

		cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);

	}

	cpu = get_cpu();

	/* Update QOS_CFG MSR on this cpu if it's in cpu_mask. */

	if (cpumask_test_cpu(cpu, cpu_mask))

		l3_qos_cfg_update(&enable);

	/* Update QOS_CFG MSR on all other cpus in cpu_mask. */

	smp_call_function_many(cpu_mask, l3_qos_cfg_update, &enable, 1);

	put_cpu();



	free_cpumask_var(cpu_mask);



	return 0;

}



static int cdp_enable(void)

{

	struct rdt_resource *r_l3data = &rdt_resources_all[RDT_RESOURCE_L3DATA];

	struct rdt_resource *r_l3code = &rdt_resources_all[RDT_RESOURCE_L3CODE];

	struct rdt_resource *r_l3 = &rdt_resources_all[RDT_RESOURCE_L3];

	int ret;



	if (!r_l3->capable || !r_l3data->capable || !r_l3code->capable)

		return -EINVAL;



	ret = set_l3_qos_cfg(r_l3, true);

	if (!ret) {

		r_l3->enabled = false;

		r_l3data->enabled = true;

		r_l3code->enabled = true;

	}

	return ret;

}



static void cdp_disable(void)

{

	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3];



	r->enabled = r->capable;



	if (rdt_resources_all[RDT_RESOURCE_L3DATA].enabled) {

		rdt_resources_all[RDT_RESOURCE_L3DATA].enabled = false;

		rdt_resources_all[RDT_RESOURCE_L3CODE].enabled = false;

		set_l3_qos_cfg(r, false);

	}

}



static int parse_rdtgroupfs_options(char *data)

{

	char *token, *o = data;

	int ret = 0;



	while ((token = strsep(&o, ",")) != NULL) {

		if (!*token)

			return -EINVAL;



		if (!strcmp(token, "cdp"))

			ret = cdp_enable();

	}



	return ret;

}



static struct dentry *rdt_mount(struct file_system_type *fs_type,

				int flags, const char *unused_dev_name,

				void *data)

{

	struct dentry *dentry;

	int ret;



	mutex_lock(&rdtgroup_mutex);

	/*

	 * resctrl file system can only be mounted once.

	 */

	if (static_branch_unlikely(&rdt_enable_key)) {

		dentry = ERR_PTR(-EBUSY);

		goto out;

	}



	ret = parse_rdtgroupfs_options(data);

	if (ret) {

		dentry = ERR_PTR(ret);

		goto out_cdp;

	}



	dentry = kernfs_mount(fs_type, flags, rdt_root,

			      RDTGROUP_SUPER_MAGIC, NULL);

	if (IS_ERR(dentry))

		goto out_cdp;



	static_branch_enable(&rdt_enable_key);

	goto out;



out_cdp:

	cdp_disable();

out:

	mutex_unlock(&rdtgroup_mutex);



	return dentry;

}



static int reset_all_cbms(struct rdt_resource *r)

{

	struct msr_param msr_param;

	cpumask_var_t cpu_mask;

	struct rdt_domain *d;

	int i, cpu;



	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))

		return -ENOMEM;



	msr_param.res = r;

	msr_param.low = 0;

	msr_param.high = r->num_closid;



	/*

	 * Disable resource control for this resource by setting all

	 * CBMs in all domains to the maximum mask value. Pick one CPU

	 * from each domain to update the MSRs below.

	 */

	list_for_each_entry(d, &r->domains, list) {

		cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);



		for (i = 0; i < r->num_closid; i++)

			d->cbm[i] = r->max_cbm;

	}

	cpu = get_cpu();

	/* Update CBM on this cpu if it's in cpu_mask. */

	if (cpumask_test_cpu(cpu, cpu_mask))

		rdt_cbm_update(&msr_param);

	/* Update CBM on all other cpus in cpu_mask. */

	smp_call_function_many(cpu_mask, rdt_cbm_update, &msr_param, 1);

	put_cpu();



	free_cpumask_var(cpu_mask);



	return 0;

}



static void rdt_kill_sb(struct super_block *sb)

{

	struct rdt_resource *r;



	mutex_lock(&rdtgroup_mutex);



	/*Put everything back to default values. */

	for_each_enabled_rdt_resource(r)

		reset_all_cbms(r);

	cdp_disable();

	static_branch_disable(&rdt_enable_key);

	kernfs_kill_sb(sb);

	mutex_unlock(&rdtgroup_mutex);

}



static struct file_system_type rdt_fs_type = {

	.name    = "resctrl",

	.mount   = rdt_mount,

	.kill_sb = rdt_kill_sb,

};



static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {

};



static int __init rdtgroup_setup_root(void)

{

	rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,

				      KERNFS_ROOT_CREATE_DEACTIVATED,

				      &rdtgroup_default);

	if (IS_ERR(rdt_root))

		return PTR_ERR(rdt_root);



	mutex_lock(&rdtgroup_mutex);



	rdtgroup_default.closid = 0;

	list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);



	rdtgroup_default.kn = rdt_root->kn;

	kernfs_activate(rdtgroup_default.kn);



	mutex_unlock(&rdtgroup_mutex);



	return 0;

}



/*

 * rdtgroup_init - rdtgroup initialization

 *

 * Setup resctrl file system including set up root, create mount point,

 * register rdtgroup filesystem, and initialize files under root directory.

 *

 * Return: 0 on success or -errno

 */

int __init rdtgroup_init(void)

{

	int ret = 0;



	ret = rdtgroup_setup_root();

	if (ret)

		return ret;



	ret = sysfs_create_mount_point(fs_kobj, "resctrl");

	if (ret)

		goto cleanup_root;



	ret = register_filesystem(&rdt_fs_type);

	if (ret)

		goto cleanup_mountpoint;



	return 0;



cleanup_mountpoint:

	sysfs_remove_mount_point(fs_kobj, "resctrl");

cleanup_root:

	kernfs_destroy_root(rdt_root);



	return ret;

}

include/uapi/linux/magic.h

+1 −0
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
#define CGROUP_SUPER_MAGIC	0x27e0eb

#define CGROUP2_SUPER_MAGIC	0x63677270



#define RDTGROUP_SUPER_MAGIC	0x7655821



#define STACK_END_MAGIC		0x57AC6E9D