[PATCH v2 01/16] fs/resctrl: Add kernel mode (kmode) data structures and arch hook

[Babu Moger]

Add resctrl_kmode, resctrl_kmode_cfg, kernel mode bit defines, and
resctrl_arch_get_kmode_cfg() for resctrl kernel mode (e.g. PLZA) support.

INHERIT_CTRL_AND_MON: kernel and user space use the same CLOSID/RMID.

GLOBAL_ASSIGN_CTRL_INHERIT_MON: When active, CLOSID/control group can be
assigned for all kernel work while all kernel work uses same RMID as user
space.

GLOBAL_ASSIGN_CTRL_ASSIGN_MON: When active the same resource group (CLOSID
and RMID) can be assigned to all the kernel work. This could be any group,
including the default group.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v2: New patch to handle PLZA interfaces with /sys/fs/resctrl/info/ directory.
    https://lore.kernel.org/lkml/2ab556af-095b-422b-9396-f845c6fd0342@xxxxxxxxx/
---
 include/linux/resctrl.h       | 10 ++++++++++
 include/linux/resctrl_types.h | 30 ++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 006e57fd7ca5..2c36d1ac392f 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -699,6 +699,16 @@ int resctrl_arch_io_alloc_enable(struct rdt_resource *r, bool enable);
  */
 bool resctrl_arch_get_io_alloc_enabled(struct rdt_resource *r);
 
+/**
+ * resctrl_arch_get_kmode_cfg() - Get resctrl kernel mode configuration
+ * @kcfg:	Filled with current kernel mode config (kmode, kmode_cur, k_rdtgrp).
+ *
+ * Used by the arch (e.g. x86) to report which kernel mode is active and,
+ * when a global assign mode is in use, which rdtgroup is assigned to
+ * kernel work.
+ */
+void resctrl_arch_get_kmode_cfg(struct resctrl_kmode_cfg *kcfg);
+
 extern unsigned int resctrl_rmid_realloc_threshold;
 extern unsigned int resctrl_rmid_realloc_limit;
 
diff --git a/include/linux/resctrl_types.h b/include/linux/resctrl_types.h
index a5f56faa18d2..6b78b08eab29 100644
--- a/include/linux/resctrl_types.h
+++ b/include/linux/resctrl_types.h
@@ -65,7 +65,37 @@ enum resctrl_event_id {
 	QOS_NUM_EVENTS,
 };
 
+/**
+ * struct resctrl_kmode - Resctrl kernel mode descriptor
+ * @name:	Human-readable name of the kernel mode.
+ * @val:	Bitmask value for the kernel mode (e.g. INHERIT_CTRL_AND_MON).
+ */
+struct resctrl_kmode {
+	char    name[32];
+	u32     val;
+};
+
+/**
+ * struct resctrl_kmode_cfg - Resctrl kernel mode configuration
+ * @kmode:	Requested kernel mode.
+ * @kmode_cur:	Currently active kernel mode.
+ * @k_rdtgrp:	Resource control structure in use, or NULL otherwise.
+ */
+struct resctrl_kmode_cfg {
+	u32 kmode;
+	u32 kmode_cur;
+	struct rdtgroup *k_rdtgrp;
+};
+
 #define QOS_NUM_L3_MBM_EVENTS	(QOS_L3_MBM_LOCAL_EVENT_ID - QOS_L3_MBM_TOTAL_EVENT_ID + 1)
 #define MBM_STATE_IDX(evt)	((evt) - QOS_L3_MBM_TOTAL_EVENT_ID)
 
+/* Resctrl kernel mode bits (e.g. for PLZA). */
+#define INHERIT_CTRL_AND_MON		BIT(0)	/* Kernel uses same CLOSID/RMID as user. */
+/* One CLOSID for all kernel work; RMID inherited from user. */
+#define GLOBAL_ASSIGN_CTRL_INHERIT_MON	BIT(1)
+/* One resource group (CLOSID+RMID) for all kernel work. */
+#define GLOBAL_ASSIGN_CTRL_ASSIGN_MON	BIT(2)
+#define RESCTRL_KERNEL_MODES_NUM	3
+
 #endif /* __LINUX_RESCTRL_TYPES_H */
-- 
2.43.0