[PATCH v4 14/19] x86/resctrl: Add the interface to assign ABMC counter

[Babu Moger]

ABMC feature requires to users to assign a hardware counter to an RMID
to monitor the events. Provide the interfaces to assign a counter.

Individual counters are configured by writing to L3_QOS_ABMC_CFG MSR
and specifying the counter id, bandwidth source, and bandwidth types.

The feature details are documented in the APM listed below [1].
[1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
    Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth
    Monitoring (ABMC).

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
---
v4: Commit message update.
    User bitmap APIs where applicable.
    Changed the interfaces considering MPAM(arm).
    Added domain specific assignment.

v3: Removed the static from the prototype of rdtgroup_assign_abmc.
    The function is not called directly from user anymore. These
    changes are related to global assignment interface.

v2: Minor text changes in commit message.
---
 arch/x86/kernel/cpu/resctrl/internal.h |   3 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 101 +++++++++++++++++++++++++
 2 files changed, 104 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 45ed33f4f0ff..a88c8fc5e4df 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -657,6 +657,9 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
 void __init resctrl_file_fflags_init(const char *config,
 				     unsigned long fflags);
 void arch_domain_mbm_evt_config(struct rdt_hw_domain *hw_dom);
+int resctrl_arch_assign(struct rdt_domain *d, u32 evtid, u32 rmid,
+			u32 ctr_id, u32 closid, bool enable);
+int resctrl_grp_assign(struct rdtgroup *rdtgrp, u32 evtid);
 void rdt_staged_configs_clear(void);
 bool closid_allocated(unsigned int closid);
 int resctrl_find_cleanest_closid(void);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 0e425c91fa46..48df76499a04 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -203,6 +203,19 @@ static void num_cntrs_init(void)
 	num_cntrs_free_map_len = r->mon.num_cntrs;
 }
 
+static int assign_cntrs_alloc(void)
+{
+	u32 ctr_id = find_first_bit(&num_cntrs_free_map,
+				    num_cntrs_free_map_len);
+
+	if (ctr_id >= num_cntrs_free_map_len)
+		return -ENOSPC;
+
+	__clear_bit(ctr_id, &num_cntrs_free_map);
+
+	return ctr_id;
+}
+
 /**
  * rdtgroup_mode_by_closid - Return mode of resource group with closid
  * @closid: closid if the resource group
@@ -1830,6 +1843,94 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of,
 	return ret ?: nbytes;
 }
 
+static void rdtgroup_abmc_cfg(void *info)
+{
+	u64 *msrval = info;
+
+	wrmsrl(MSR_IA32_L3_QOS_ABMC_CFG, *msrval);
+}
+
+int resctrl_arch_assign(struct rdt_domain *d, u32 evtid, u32 rmid,
+			u32 ctr_id, u32 closid, bool enable)
+{
+	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
+	union l3_qos_abmc_cfg abmc_cfg = { 0 };
+	struct arch_mbm_state *arch_mbm;
+
+	abmc_cfg.split.cfg_en = 1;
+	abmc_cfg.split.ctr_en = enable ? 1 : 0;
+	abmc_cfg.split.ctr_id = ctr_id;
+	abmc_cfg.split.bw_src = rmid;
+
+	/*
+	 * Read the event configuration from the domain and pass it as
+	 * bw_type.
+	 */
+	if (evtid == QOS_L3_MBM_TOTAL_EVENT_ID) {
+		abmc_cfg.split.bw_type = hw_dom->mbm_total_cfg;
+		arch_mbm = &hw_dom->arch_mbm_total[rmid];
+	} else {
+		abmc_cfg.split.bw_type = hw_dom->mbm_local_cfg;
+		arch_mbm = &hw_dom->arch_mbm_local[rmid];
+	}
+
+	smp_call_function_any(&d->cpu_mask, rdtgroup_abmc_cfg, &abmc_cfg, 1);
+
+	/* Reset the internal counters */
+	if (arch_mbm)
+		memset(arch_mbm, 0, sizeof(struct arch_mbm_state));
+
+	return 0;
+}
+
+int resctrl_grp_assign(struct rdtgroup *rdtgrp, u32 evtid)
+{
+	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+	int ctr_id = 0, index;
+	struct rdt_domain *d;
+	u32 mon_state;
+
+	index = mon_event_config_index_get(evtid);
+	if (index == INVALID_CONFIG_INDEX) {
+		rdt_last_cmd_puts("Invalid event id\n");
+		return -EINVAL;
+	}
+
+	if (evtid == QOS_L3_MBM_TOTAL_EVENT_ID) {
+		mon_state = ASSIGN_TOTAL;
+	} else if (evtid == QOS_L3_MBM_LOCAL_EVENT_ID) {
+		mon_state = ASSIGN_LOCAL;
+	} else {
+		rdt_last_cmd_puts("Invalid event id\n");
+		return -EINVAL;
+	}
+
+	/* Nothing to do if event has been assigned already */
+	if (rdtgrp->mon.mon_state & mon_state) {
+		rdt_last_cmd_puts("ABMC counter is assigned already\n");
+		return 0;
+	}
+
+	/*
+	 * Allocate a new counter and update domains
+	 */
+	ctr_id = assign_cntrs_alloc();
+	if (ctr_id < 0) {
+		rdt_last_cmd_puts("Out of ABMC counters\n");
+		return -ENOSPC;
+	}
+
+	rdtgrp->mon.ctr_id[index] = ctr_id;
+
+	list_for_each_entry(d, &r->domains, list)
+		resctrl_arch_assign(d, evtid, rdtgrp->mon.rmid, ctr_id,
+				    rdtgrp->closid, 1);
+
+	rdtgrp->mon.mon_state |= mon_state;
+
+	return 0;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_common_files[] = {
 	{
-- 
2.34.1