[RFC PATCH v3 03/17] x86/resctrl: Detect Assignable Bandwidth Monitoring feature details

Babu Moger
2024-03-29T01:07:28Z

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