[PATCH v7 19/49] x86/resctrl: Add resctrl_arch_is_evt_configurable() to abstract BMEC

James Morse
2025-02-28T20:01:08Z

When BMEC is supported the resctrl event can be configured in a number
of ways. This depends on architecture support. rdt_get_mon_l3_config()
modifies the struct mon_evt and calls mbm_config_rftype_init() to create
the files that allow the configuration.

Splitting this into separate architecture and filesystem parts would
require the struct mon_evt and mbm_config_rftype_init() to be exposed.

Instead, add resctrl_arch_is_evt_configurable(), and use this from
resctrl_mon_resource_init() to initialise struct mon_evt and call
resctrl_file_fflags_init()
resctrl_arch_is_evt_configurable() calls rdt_cpu_has() so it doesn't
obviously benefit from being inlined. Putting it in core.c will allow
rdt_cpu_has() to eventually become static.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
---
Changes since v6:
* Fixed stale function name in the commit message.
* Moved __init around in the function prototypes.

Changes since v4:
* Moved all the __init changes to a later patch now that the exit gubbins
comes first.
---
arch/x86/kernel/cpu/resctrl/core.c | 15 +++++++++++++++
arch/x86/kernel/cpu/resctrl/monitor.c | 22 +++++++++++-----------
include/linux/resctrl.h | 2 ++
3 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 5464dc1611e9..943e4c56077b 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -832,6 +832,21 @@ bool __init rdt_cpu_has(int flag)
return ret;
}

+__init bool resctrl_arch_is_evt_configurable(enum resctrl_event_id evt)
+{
+ if (!rdt_cpu_has(X86_FEATURE_BMEC))
+ return false;
+
+ switch (evt) {
+ case QOS_L3_MBM_TOTAL_EVENT_ID:
+ return rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL);
+ case QOS_L3_MBM_LOCAL_EVENT_ID:
+ return rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL);
+ default:
+ return false;
+ }
+}
+
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/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index d883ed56ec90..27d983121b0a 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1202,6 +1202,17 @@ int __init resctrl_mon_resource_init(void)

l3_mon_evt_init(r);

+ if (resctrl_arch_is_evt_configurable(QOS_L3_MBM_TOTAL_EVENT_ID)) {
+ mbm_total_event.configurable = true;
+ resctrl_file_fflags_init("mbm_total_bytes_config",
+ RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
+ }
+ if (resctrl_arch_is_evt_configurable(QOS_L3_MBM_LOCAL_EVENT_ID)) {
+ mbm_local_event.configurable = true;
+ resctrl_file_fflags_init("mbm_local_bytes_config",
+ RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
+ }
+
return 0;
}

@@ -1245,17 +1256,6 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
/* Detect list of bandwidth sources that can be tracked */
cpuid_count(0x80000020, 3, &eax, &ebx, &ecx, &edx);
hw_res->mbm_cfg_mask = ecx & MAX_EVT_CONFIG_BITS;
-
- if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL)) {
- mbm_total_event.configurable = true;
- resctrl_file_fflags_init("mbm_total_bytes_config",
- RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
- }
- if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL)) {
- mbm_local_event.configurable = true;
- resctrl_file_fflags_init("mbm_local_bytes_config",
- RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
- }
}

r->mon_capable = true;
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index a392480dc4b6..cc76f308e6f3 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -309,6 +309,8 @@ u32 resctrl_arch_get_num_closid(struct rdt_resource *r);
u32 resctrl_arch_system_num_rmid_idx(void);
int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);

+__init bool resctrl_arch_is_evt_configurable(enum resctrl_event_id evt);
+
/*
* Update the ctrl_val and apply this config right now.
* Must be called on one of the domain's CPUs.
--
2.39.5