[PATCH v2 6/7] x86/resctrl: Introduce interface to display io_alloc CBMs

[Babu Moger <babu.moger@amd.com>]

The io_alloc feature in resctrl enables system software to configure
the portion of the L3 cache allocated for I/O traffic.

Add the interface to display CBMs (Capacity Bit Mask) of io_alloc
feature.

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v2: Fixed to display only on L3 resources.
    Added the locks while processing.
    Rename the displat to io_alloc_cbm (from sdciae_cmd).
---
 arch/x86/kernel/cpu/resctrl/core.c        |  2 ++
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c |  2 +-
 arch/x86/kernel/cpu/resctrl/internal.h    |  1 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 33 +++++++++++++++++++++++
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 066a7997eaf1..f1ac7af7b366 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -311,6 +311,8 @@ static void rdt_get_sdciae_alloc_cfg(struct rdt_resource *r)
 	r->cache.io_alloc_capable = true;
 	resctrl_file_fflags_init("io_alloc",
 				 RFTYPE_CTRL_INFO | RFTYPE_RES_CACHE);
+	resctrl_file_fflags_init("io_alloc_cbm",
+				 RFTYPE_CTRL_INFO | RFTYPE_RES_CACHE);
 }
 
 static void rdt_get_cdp_l3_config(void)
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 536351159cc2..d272dea43924 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -444,7 +444,7 @@ u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_ctrl_domain *d,
 	return hw_dom->ctrl_val[idx];
 }
 
-static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int closid)
+void show_doms(struct seq_file *s, struct resctrl_schema *schema, int closid)
 {
 	struct rdt_resource *r = schema->res;
 	struct rdt_ctrl_domain *dom;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index dff3354c2282..1550cb468b8e 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -668,4 +668,5 @@ void resctrl_file_fflags_init(const char *config, unsigned long fflags);
 void rdt_staged_configs_clear(void);
 bool closid_allocated(unsigned int closid);
 int resctrl_find_cleanest_closid(void);
+void show_doms(struct seq_file *s, struct resctrl_schema *schema, int closid);
 #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e30731ce9335..4d6b83d18790 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1943,6 +1943,33 @@ static ssize_t resctrl_io_alloc_write(struct kernfs_open_file *of, char *buf,
 	return ret ?: nbytes;
 }
 
+static int resctrl_io_alloc_cbm_show(struct kernfs_open_file *of,
+				     struct seq_file *seq, void *v)
+{
+	struct resctrl_schema *s = of->kn->parent->priv;
+	struct rdt_resource *r = s->res;
+	u32 io_alloc_closid;
+	int ret = 0;
+
+	cpus_read_lock();
+	mutex_lock(&rdtgroup_mutex);
+
+	if (!resctrl_arch_get_io_alloc_enabled(r->rid)) {
+		rdt_last_cmd_puts("io_alloc feature is not enabled\n");
+		ret = -EINVAL;
+		goto cbm_show_out;
+	}
+
+	io_alloc_closid = resctrl_io_alloc_closid_get(r);
+
+	show_doms(seq, s, io_alloc_closid);
+
+cbm_show_out:
+	mutex_unlock(&rdtgroup_mutex);
+	cpus_read_unlock();
+	return ret;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_common_files[] = {
 	{
@@ -2102,6 +2129,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= resctrl_io_alloc_show,
 		.write		= resctrl_io_alloc_write,
 	},
+	{
+		.name		= "io_alloc_cbm",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= resctrl_io_alloc_cbm_show,
+	},
 	{
 		.name		= "mba_MBps_event",
 		.mode		= 0644,
-- 
2.34.1