mon_event_config_{read,write}() are called via IPI and access model
specific registers to do their work.

To support another architecture, this needs abstracting.

Rename mon_event_config_{read,write}() to have a "resctrl_arch_"
prefix, and move their struct mon_config_info parameter into
<linux/resctrl.h>.  This allows another architecture to supply an
implementation of these.

As struct mon_config_info is now exposed globally, give it a 'resctrl_'
prefix. MPAM systems need access to the domain to do this work, add
the resource and domain to struct resctrl_mon_config_info.

Co-developed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
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>
---
Changes since v3:
 * Added comments over the read/write helper to explain the type of the void
   pointer.

Changes since v1:
 * [Whitespace only] Re-tabbed struct resctrl_mon_config_info in
   <linux/resctrl.h> to fit the prevailing style.

   Non-functional change.

 * [Commit message only] Reword to align with the actual naming of the
   definitions and destination header file.
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 34 +++++++++++++-------------
 include/linux/resctrl.h                | 25 +++++++++++++++++++
 2 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 9294bf74f3a8..304fdf199de7 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1571,11 +1571,6 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 	return ret;
 }
 
-struct mon_config_info {
-	u32 evtid;
-	u32 mon_config;
-};
-
 #define INVALID_CONFIG_INDEX   UINT_MAX
 
 /**
@@ -1600,9 +1595,9 @@ static inline unsigned int mon_event_config_index_get(u32 evtid)
 	}
 }
 
-static void mon_event_config_read(void *info)
+void resctrl_arch_mon_event_config_read(void *info)
 {
-	struct mon_config_info *mon_info = info;
+	struct resctrl_mon_config_info *mon_info = info;
 	unsigned int index;
 	u64 msrval;
 
@@ -1617,14 +1612,15 @@ static void mon_event_config_read(void *info)
 	mon_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
 }
 
-static void mondata_config_read(struct rdt_mon_domain *d, struct mon_config_info *mon_info)
+static void mondata_config_read(struct resctrl_mon_config_info *mon_info)
 {
-	smp_call_function_any(&d->hdr.cpu_mask, mon_event_config_read, mon_info, 1);
+	smp_call_function_any(&mon_info->d->hdr.cpu_mask,
+			      resctrl_arch_mon_event_config_read, mon_info, 1);
 }
 
 static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid)
 {
-	struct mon_config_info mon_info;
+	struct resctrl_mon_config_info mon_info;
 	struct rdt_mon_domain *dom;
 	bool sep = false;
 
@@ -1635,9 +1631,11 @@ static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid
 		if (sep)
 			seq_puts(s, ";");
 
-		memset(&mon_info, 0, sizeof(struct mon_config_info));
+		memset(&mon_info, 0, sizeof(struct resctrl_mon_config_info));
+		mon_info.r = r;
+		mon_info.d = dom;
 		mon_info.evtid = evtid;
-		mondata_config_read(dom, &mon_info);
+		mondata_config_read(&mon_info);
 
 		seq_printf(s, "%d=0x%02x", dom->hdr.id, mon_info.mon_config);
 		sep = true;
@@ -1670,9 +1668,9 @@ static int mbm_local_bytes_config_show(struct kernfs_open_file *of,
 	return 0;
 }
 
-static void mon_event_config_write(void *info)
+void resctrl_arch_mon_event_config_write(void *info)
 {
-	struct mon_config_info *mon_info = info;
+	struct resctrl_mon_config_info *mon_info = info;
 	unsigned int index;
 
 	index = mon_event_config_index_get(mon_info->evtid);
@@ -1686,14 +1684,16 @@ static void mon_event_config_write(void *info)
 static void mbm_config_write_domain(struct rdt_resource *r,
 				    struct rdt_mon_domain *d, u32 evtid, u32 val)
 {
-	struct mon_config_info mon_info = {0};
+	struct resctrl_mon_config_info mon_info = {0};
 
 	/*
 	 * Read the current config value first. If both are the same then
 	 * no need to write it again.
 	 */
+	mon_info.r = r;
+	mon_info.d = d;
 	mon_info.evtid = evtid;
-	mondata_config_read(d, &mon_info);
+	mondata_config_read(&mon_info);
 	if (mon_info.mon_config == val)
 		return;
 
@@ -1705,7 +1705,7 @@ static void mbm_config_write_domain(struct rdt_resource *r,
 	 * 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->hdr.cpu_mask, mon_event_config_write,
+	smp_call_function_any(&d->hdr.cpu_mask, resctrl_arch_mon_event_config_write,
 			      &mon_info, 1);
 
 	/*
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 224a14d9aa7a..0072c2e5947f 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -271,6 +271,13 @@ struct resctrl_cpu_defaults {
 	u32 rmid;
 };
 
+struct resctrl_mon_config_info {
+	struct rdt_resource	*r;
+	struct rdt_mon_domain	*d;
+	u32			evtid;
+	u32			mon_config;
+};
+
 /**
  * resctrl_arch_sync_cpu_closid_rmid() - Refresh this CPU's CLOSID and RMID.
  *					 Call via IPI.
@@ -315,6 +322,24 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);
 
 bool __init resctrl_arch_is_evt_configurable(enum resctrl_event_id evt);
 
+/**
+ * resctrl_arch_mon_event_config_write() - Write the config for a counter.
+ * @info:	struct resctrl_mon_config_info describing the resource, domain
+ *		and event.
+ *
+ * Must be called on a CPU that is a member of the specified domain.
+ */
+void resctrl_arch_mon_event_config_write(void *info);
+
+/**
+ * resctrl_arch_mon_event_config_read() - Read the config for a counter.
+ * @info:	struct resctrl_mon_config_info describing the resource, domain
+ *		and event.
+ *
+ * Must be called on a CPU that is a member of the specified domain.
+ */
+void resctrl_arch_mon_event_config_read(void *info);
+
 /*
  * Update the ctrl_val and apply this config right now.
  * Must be called on one of the domain's CPUs.
-- 
2.39.2

Hi James,

On 10/4/24 11:03 AM, James Morse wrote:
> @@ -315,6 +322,24 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);
>  
>  bool __init resctrl_arch_is_evt_configurable(enum resctrl_event_id evt);
>  
> +/**
> + * resctrl_arch_mon_event_config_write() - Write the config for a counter.

Please avoid the term "counter" for events ... the upcoming AMD work adds support
for counters*. 

> + * @info:	struct resctrl_mon_config_info describing the resource, domain
> + *		and event.

Expected "config" to appear as part of information about function
that claims to writes config?

> + *
> + * Must be called on a CPU that is a member of the specified domain.

I am not sure about this. Is this documentation intended to support authors of
arch code? In that case it may be instead useful to know that this function will be
called on a CPU that is a member of the specified domain to avoid confusion from arch
side whether it needs to take some action to ensure function is called on right CPU.

	Called on a CPU that is a member of the specified domain.

> + */
> +void resctrl_arch_mon_event_config_write(void *info);
> +
> +/**
> + * resctrl_arch_mon_event_config_read() - Read the config for a counter.

counter -> event

> + * @info:	struct resctrl_mon_config_info describing the resource, domain
> + *		and event.

Copy&paste? No information on how config is returned.

> + *
> + * Must be called on a CPU that is a member of the specified domain.

Same comment as above.

> + */
> +void resctrl_arch_mon_event_config_read(void *info);
> +
>  /*
>   * Update the ctrl_val and apply this config right now.
>   * Must be called on one of the domain's CPUs.

Reinette


* Awaiting Arm's feedback on that on whether it works for MPAM.