Commit 92bd5a13 authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Add interface to write mbm_total_bytes_config 



The event configuration for mbm_total_bytes can be changed by the user by
writing to the file /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config.

The event configuration settings are domain specific and affect all the
CPUs in the domain.

Following are the types of events supported:

  ====  ===========================================================
  Bits   Description
  ====  ===========================================================
  6      Dirty Victims from the QOS domain to all types of memory
  5      Reads to slow memory in the non-local NUMA domain
  4      Reads to slow memory in the local NUMA domain
  3      Non-temporal writes to non-local NUMA domain
  2      Non-temporal writes to local NUMA domain
  1      Reads to memory in the non-local NUMA domain
  0      Reads to memory in the local NUMA domain
  ====  ===========================================================

For example:

To change the mbm_total_bytes to count only reads on domain 0, the bits
0, 1, 4 and 5 needs to be set, which is 110011b (in hex 0x33).
Run the command:

  $echo  0=0x33 > /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config

To change the mbm_total_bytes to count all the slow memory reads on domain 1,
the bits 4 and 5 needs to be set which is 110000b (in hex 0x30).
Run the command:

  $echo  1=0x30 > /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config

Signed-off-by: default avatarBabu Moger <babu.moger@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-12-babu.moger@amd.com
parent 73afb2d3

arch/x86/kernel/cpu/resctrl/monitor.c

+17 −0
Original line number Diff line number Diff line
@@ -204,6 +204,23 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d, 
	}

}



/*

 * Assumes that hardware counters are also reset and thus that there is

 * no need to record initial non-zero counts.

 */

void resctrl_arch_reset_rmid_all(struct rdt_resource *r, struct rdt_domain *d)

{

	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);



	if (is_mbm_total_enabled())

		memset(hw_dom->arch_mbm_total, 0,

		       sizeof(*hw_dom->arch_mbm_total) * r->num_rmid);



	if (is_mbm_local_enabled())

		memset(hw_dom->arch_mbm_local, 0,

		       sizeof(*hw_dom->arch_mbm_local) * r->num_rmid);

}



static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width)

{

	u64 shift = 64 - width, chunks;

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+123 −1
Original line number Diff line number Diff line
@@ -1517,6 +1517,127 @@ static int mbm_local_bytes_config_show(struct kernfs_open_file *of, 
	return 0;

}



static void mon_event_config_write(void *info)

{

	struct mon_config_info *mon_info = info;

	unsigned int index;



	index = mon_event_config_index_get(mon_info->evtid);

	if (index == INVALID_CONFIG_INDEX) {

		pr_warn_once("Invalid event id %d\n", mon_info->evtid);

		return;

	}

	wrmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, 0);

}



static int mbm_config_write_domain(struct rdt_resource *r,

				   struct rdt_domain *d, u32 evtid, u32 val)

{

	struct mon_config_info mon_info = {0};

	int ret = 0;



	/* mon_config cannot be more than the supported set of events */

	if (val > MAX_EVT_CONFIG_BITS) {

		rdt_last_cmd_puts("Invalid event configuration\n");

		return -EINVAL;

	}



	/*

	 * Read the current config value first. If both are the same then

	 * no need to write it again.

	 */

	mon_info.evtid = evtid;

	mondata_config_read(d, &mon_info);

	if (mon_info.mon_config == val)

		goto out;



	mon_info.mon_config = val;



	/*

	 * Update MSR_IA32_EVT_CFG_BASE MSR on one of the CPUs in the

	 * domain. The MSRs offset from MSR MSR_IA32_EVT_CFG_BASE

	 * are scoped at the domain level. Writing any of these MSRs

	 * on one CPU is observed by all the CPUs in the domain.

	 */

	smp_call_function_any(&d->cpu_mask, mon_event_config_write,

			      &mon_info, 1);



	/*

	 * When an Event Configuration is changed, the bandwidth counters

	 * for all RMIDs and Events will be cleared by the hardware. The

	 * hardware also sets MSR_IA32_QM_CTR.Unavailable (bit 62) for

	 * every RMID on the next read to any event for every RMID.

	 * Subsequent reads will have MSR_IA32_QM_CTR.Unavailable (bit 62)

	 * cleared while it is tracked by the hardware. Clear the

	 * mbm_local and mbm_total counts for all the RMIDs.

	 */

	resctrl_arch_reset_rmid_all(r, d);



out:

	return ret;

}



static int mon_config_write(struct rdt_resource *r, char *tok, u32 evtid)

{

	char *dom_str = NULL, *id_str;

	unsigned long dom_id, val;

	struct rdt_domain *d;

	int ret = 0;



next:

	if (!tok || tok[0] == '\0')

		return 0;



	/* Start processing the strings for each domain */

	dom_str = strim(strsep(&tok, ";"));

	id_str = strsep(&dom_str, "=");



	if (!id_str || kstrtoul(id_str, 10, &dom_id)) {

		rdt_last_cmd_puts("Missing '=' or non-numeric domain id\n");

		return -EINVAL;

	}



	if (!dom_str || kstrtoul(dom_str, 16, &val)) {

		rdt_last_cmd_puts("Non-numeric event configuration value\n");

		return -EINVAL;

	}



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

		if (d->id == dom_id) {

			ret = mbm_config_write_domain(r, d, evtid, val);

			if (ret)

				return -EINVAL;

			goto next;

		}

	}



	return -EINVAL;

}



static ssize_t mbm_total_bytes_config_write(struct kernfs_open_file *of,

					    char *buf, size_t nbytes,

					    loff_t off)

{

	struct rdt_resource *r = of->kn->parent->priv;

	int ret;



	/* Valid input requires a trailing newline */

	if (nbytes == 0 || buf[nbytes - 1] != '\n')

		return -EINVAL;



	mutex_lock(&rdtgroup_mutex);



	rdt_last_cmd_clear();



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



	ret = mon_config_write(r, buf, QOS_L3_MBM_TOTAL_EVENT_ID);



	mutex_unlock(&rdtgroup_mutex);



	return ret ?: nbytes;

}



/* rdtgroup information files for one cache resource. */

static struct rftype res_common_files[] = {

	{
@@ -1617,9 +1738,10 @@ static struct rftype res_common_files[] = { 
	},

	{

		.name		= "mbm_total_bytes_config",

		.mode		= 0444,

		.mode		= 0644,

		.kf_ops		= &rdtgroup_kf_single_ops,

		.seq_show	= mbm_total_bytes_config_show,

		.write		= mbm_total_bytes_config_write,

	},

	{

		.name		= "mbm_local_bytes_config",

include/linux/resctrl.h

+11 −0
Original line number Diff line number Diff line
@@ -250,6 +250,17 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, 
void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d,

			     u32 rmid, enum resctrl_event_id eventid);



/**

 * resctrl_arch_reset_rmid_all() - Reset all private state associated with

 *				   all rmids and eventids.

 * @r:		The resctrl resource.

 * @d:		The domain for which all architectural counter state will

 *		be cleared.

 *

 * This can be called from any CPU.

 */

void resctrl_arch_reset_rmid_all(struct rdt_resource *r, struct rdt_domain *d);



extern unsigned int resctrl_rmid_realloc_threshold;

extern unsigned int resctrl_rmid_realloc_limit;