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From: Babu Moger <babu.moger@amd.com>
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Subject: [RFC PATCH v3 03/17] x86/resctrl: Detect Assignable Bandwidth Monitoring feature details
Date: Thu, 28 Mar 2024 20:06:36 -0500
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ABMC feature details are reported via CPUID Fn8000_0020_EBX_x5.
Bits Description
15:0 MAX_ABMC Maximum Supported Assignable Bandwidth
     Monitoring Counter ID + 1

The feature details are documented in 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@amd.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
---
v3: Removed changes related to mon_features.
    Moved rdt_cpu_has to core.c and added new function resctrl_arch_has_abmc.
    Also moved the fields mbm_assign_capable and mbm_assign_cntrs to
    rdt_resource. (James)

v2: Changed the field name to mbm_assign_capable from abmc_capable.
---
 arch/x86/kernel/cpu/resctrl/core.c     | 17 +++++++++++++++++
 arch/x86/kernel/cpu/resctrl/internal.h |  1 +
 arch/x86/kernel/cpu/resctrl/monitor.c  |  3 +++
 include/linux/resctrl.h                | 12 ++++++++++++
 4 files changed, 33 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 57a8c6f30dd6..bb82b392cf5d 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -740,6 +740,23 @@ bool __init rdt_cpu_has(int flag)
 	return ret;
 }
 
+inline bool __init resctrl_arch_has_abmc(struct rdt_resource *r)
+{
+	bool ret = rdt_cpu_has(X86_FEATURE_ABMC);
+	u32 eax, ebx, ecx, edx;
+
+	if (ret) {
+		/*
+		 * Query CPUID_Fn80000020_EBX_x05 for number of
+		 * ABMC counters
+		 */
+		cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
+		r->mbm_assign_cntrs = (ebx & 0xFFFF) + 1;
+	}
+
+	return ret;
+}
+
 static __init bool get_mem_config(void)
 {
 	struct rdt_hw_resource *hw_res = &rdt_resources_all[RDT_RESOURCE_MBA];
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index c99f26ebe7a6..c4ae6f3993aa 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -584,6 +584,7 @@ void free_rmid(u32 closid, u32 rmid);
 int rdt_get_mon_l3_config(struct rdt_resource *r);
 void __exit rdt_put_mon_l3_config(void);
 bool __init rdt_cpu_has(int flag);
+bool __init resctrl_arch_has_abmc(struct rdt_resource *r);
 void mon_event_count(void *info);
 int rdtgroup_mondata_show(struct seq_file *m, void *arg);
 void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index c34a35ec0f03..e5938bf53d5a 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1055,6 +1055,9 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
 			mbm_local_event.configurable = true;
 			mbm_config_rftype_init("mbm_local_bytes_config");
 		}
+
+		if (resctrl_arch_has_abmc(r))
+			r->mbm_assign_capable = ABMC_ASSIGN;
 	}
 
 	l3_mon_evt_init(r);
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index a365f67131ec..a1ee9afabff3 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -150,6 +150,14 @@ struct resctrl_membw {
 struct rdt_parse_data;
 struct resctrl_schema;
 
+/**
+ * enum mbm_assign_type - The type of assignable monitoring.
+ * @ABMC_ASSIGN: Assignable Bandwidth Monitoring Counters.
+ */
+enum mbm_assign_type {
+	ABMC_ASSIGN	= 0x01,
+};
+
 /**
  * struct rdt_resource - attributes of a resctrl resource
  * @rid:		The index of the resource
@@ -168,6 +176,8 @@ struct resctrl_schema;
  * @evt_list:		List of monitoring events
  * @fflags:		flags to choose base and info files
  * @cdp_capable:	Is the CDP feature available on this resource
+ * @mbm_assign_capable:	Does system capable of supporting monitor assignment?
+ * @mbm_assign_cntrs:	Maximum number of assignable counters
  */
 struct rdt_resource {
 	int			rid;
@@ -188,6 +198,8 @@ struct rdt_resource {
 	struct list_head	evt_list;
 	unsigned long		fflags;
 	bool			cdp_capable;
+	bool			mbm_assign_capable;
+	u32                     mbm_assign_cntrs;
 };
 
 /**
-- 
2.34.1