[PATCH 00/10] Add sysfs interface files to hv_gpci device to expose system information

[PATCH 00/10] Add sysfs interface files to hv_gpci device to expose system information

[Kajol Jain]

The hcall H_GET_PERF_COUNTER_INFO can be used to get data related to
chips, dimms and system topology, by passing different counter request
values.
Patchset adds sysfs files to "/sys/devices/hv_gpci/interface/"
of hv_gpci pmu driver, which will expose system topology information
using H_GET_PERF_COUNTER_INFO hcall. The added sysfs files are
available for power10 and above platforms and needs root access
to read the data.

Patches 1,3,5,7,9 adds sysfs interface files to the hv_gpci
pmu driver, to get system topology information.

List of added sysfs files:
-> processor_bus_topology (Counter request value : 0xD0)
-> processor_config (Counter request value : 0x90)
-> affinity_domain_via_virtual_processor (Counter request value : 0xA0)
-> affinity_domain_via_domain (Counter request value : 0xB0)
-> affinity_domain_via_partition (Counter request value : 0xB1)

Patches 2,4,6,8,10 adds details of the newly added hv_gpci
interface files listed above in the ABI documentation.

Kajol Jain (10):
  powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show
    processor bus topology information
  docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document
    processor_bus_topology sysfs interface file
  powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show
    processor config information
  docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document
    processor_config sysfs interface file
  powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity
    domain via virtual processor information
  docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document
    affinity_domain_via_virtual_processor sysfs interface file
  powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity
    domain via domain information
  docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document
    affinity_domain_via_domain sysfs interface file
  powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity
    domain via partition information
  docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document
    affinity_domain_via_partition sysfs interface file

 .../sysfs-bus-event_source-devices-hv_gpci    |  89 +++
 arch/powerpc/perf/hv-gpci.c                   | 584 +++++++++++++++++-
 arch/powerpc/perf/hv-gpci.h                   |  15 +
 3 files changed, 686 insertions(+), 2 deletions(-)

-- 
2.35.3

[PATCH 01/10] powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show processor bus topology information

[Kajol Jain]

The hcall H_GET_PERF_COUNTER_INFO with counter request value as
PROCESSOR_BUS_TOPOLOGY(0XD0), can be used to get the system
topology information. To expose the system topology information,
patch adds sysfs file called "processor_bus_topology" to the
"/sys/devices/hv_gpci/interface/" of hv_gpci pmu driver.

Add macro for PROCESSOR_BUS_TOPOLOGY counter request value
in hv-gpci.h file. Also add a new function called
"systeminfo_gpci_request", to make the H_GET_PERF_COUNTER_INFO hcall
with added macro, and populates the output buffer.

The processor_bus_topology sysfs file is only available for power10
and above platforms. Add a new function called
"add_sysinfo_interface_files", which will add processor_bus_topology
attribute in the interface_attrs array, only for power10 and
above platforms.
Also add macro INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR in hv-gpci.h
file, which points to the index of NULL placefolder, for
processor_bus_topology attribute.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 163 +++++++++++++++++++++++++++++++++++-
 arch/powerpc/perf/hv-gpci.h |   6 ++
 2 files changed, 167 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 7ff8ff3509f5..bca24725699e 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -102,6 +102,141 @@ static ssize_t cpumask_show(struct device *dev,
 	return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);
 }
 
+static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
+
+static unsigned long systeminfo_gpci_request(u32 req, u32 starting_index,
+			u16 secondary_index, char *buf,
+			size_t *n, struct hv_gpci_request_buffer *arg)
+{
+	unsigned long ret;
+	size_t i, j;
+
+	arg->params.counter_request = cpu_to_be32(req);
+	arg->params.starting_index = cpu_to_be32(starting_index);
+	arg->params.secondary_index = cpu_to_be16(secondary_index);
+
+	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL',
+	 * which means that the current buffer size cannot accommodate
+	 * all the information and a partial buffer returned.
+	 * hcall fails incase of ret value other than H_SUCCESS or H_PARAMETER.
+	 *
+	 * ret value as H_AUTHORITY implies that partition is not permitted to retrieve
+	 * performance information, and required to set
+	 * "Enable Performance Information Collection" option.
+	 */
+	if (ret == H_AUTHORITY)
+		return -EPERM;
+
+	/*
+	 * ret value as H_NOT_AVAILABLE implies that requested system information is
+	 * not available for the firmware level and platform.
+	 */
+	if (ret == H_NOT_AVAILABLE)
+		return -EOPNOTSUPP;
+
+	/*
+	 * hcall can fail with other possible ret value like H_PRIVILEGE/H_HARDWARE
+	 * because of invalid buffer-length/address or due to some hardware
+	 * error.
+	 */
+	if (ret && (ret != H_PARAMETER))
+		return -EIO;
+
+	/*
+	 * hcall H_GET_PERF_COUNTER_INFO populates the 'returned_values'
+	 * to show the total number of counter_value array elements
+	 * returned via hcall.
+	 * hcall also populates 'cv_element_size' corresponds to individual
+	 * counter_value array element size. Below loop go through all
+	 * counter_value array elements as per their size and add it to
+	 * the output buffer.
+	 */
+	for (i = 0; i < be16_to_cpu(arg->params.returned_values); i++) {
+		j = i * be16_to_cpu(arg->params.cv_element_size);
+
+		for (; j < (i + 1) * be16_to_cpu(arg->params.cv_element_size); j++)
+			*n += sprintf(buf + *n,  "%02x", (u8)arg->bytes[j]);
+		*n += sprintf(buf + *n,  "\n");
+	}
+
+	if (*n >= PAGE_SIZE) {
+		pr_info("System information exceeds PAGE_SIZE\n");
+		return -EFBIG;
+	}
+
+	return ret;
+}
+
+static ssize_t processor_bus_topology_show(struct device *dev, struct device_attribute *attr,
+				char *buf)
+{
+	struct hv_gpci_request_buffer *arg;
+	unsigned long ret;
+	size_t n = 0;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * Pass the counter request value 0xD0 corresponds to request
+	 * type 'Processor_bus_topology', to retrieve
+	 * the system topology information.
+	 * starting_index value implies the starting hardware
+	 * chip id.
+	 */
+	ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, 0, 0, buf, &n, arg);
+
+	if (!ret)
+		return n;
+
+	if (ret != H_PARAMETER)
+		goto out;
+
+	/*
+	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL', which
+	 * implies that buffer can't accommodate all information, and a partial buffer
+	 * returned. To handle that, we need to make subsequent requests
+	 * with next starting index to retrieve additional (missing) data.
+	 * Below loop do subsequent hcalls with next starting index and add it
+	 * to buffer util we get all the information.
+	 */
+	while (ret == H_PARAMETER) {
+		int returned_values = be16_to_cpu(arg->params.returned_values);
+		int elementsize = be16_to_cpu(arg->params.cv_element_size);
+		int last_element = (returned_values - 1) * elementsize;
+
+		/*
+		 * Since the starting index value is part of counter_value
+		 * buffer elements, use the starting index value in the last
+		 * element and add 1 to make subsequent hcalls.
+		 */
+		u32 starting_index = arg->bytes[last_element + 3] +
+				(arg->bytes[last_element + 2] << 8) +
+				(arg->bytes[last_element + 1] << 16) +
+				(arg->bytes[last_element] << 24) + 1;
+
+		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+		ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, starting_index,
+				0, buf, &n, arg);
+
+		if (!ret)
+			return n;
+
+		if (ret != H_PARAMETER)
+			goto out;
+	}
+
+	return n;
+out:
+	put_cpu_var(hv_gpci_reqb);
+	return ret;
+}
+
 static DEVICE_ATTR_RO(kernel_version);
 static DEVICE_ATTR_RO(cpumask);
 
@@ -118,6 +253,11 @@ static struct attribute *interface_attrs[] = {
 	&hv_caps_attr_expanded.attr,
 	&hv_caps_attr_lab.attr,
 	&hv_caps_attr_collect_privileged.attr,
+	/*
+	 * This NULL is a placeholder for the processor_bus_topology
+	 * attribute, set in init function if applicable.
+	 */
+	NULL,
 	NULL,
 };
 
@@ -143,8 +283,6 @@ static const struct attribute_group *attr_groups[] = {
 	NULL,
 };
 
-static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
-
 static unsigned long single_gpci_request(u32 req, u32 starting_index,
 		u16 secondary_index, u8 version_in, u32 offset, u8 length,
 		u64 *value)
@@ -325,6 +463,23 @@ static int hv_gpci_cpu_hotplug_init(void)
 			  ppc_hv_gpci_cpu_offline);
 }
 
+static void add_sysinfo_interface_files(void)
+{
+	struct device_attribute *attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+
+	if (!attr) {
+		pr_info("Memory allocation failed for processor_bug_topology interface file\n");
+		return;
+	}
+
+	/* Add processor_bus_topology attribute in the interface_attrs attribute array */
+	sysfs_attr_init(&attr->attr);
+	attr->attr.name = "processor_bug_topology";
+	attr->attr.mode = 0444;
+	attr->show = processor_bus_topology_show;
+	interface_attrs[INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR] = &attr->attr;
+}
+
 static int hv_gpci_init(void)
 {
 	int r;
@@ -388,6 +543,10 @@ static int hv_gpci_init(void)
 	if (r)
 		return r;
 
+	/* sysinfo interface files are only available for power10 and above platforms */
+	if (PVR_VER(mfspr(SPRN_PVR)) >= PVR_POWER10)
+		add_sysinfo_interface_files();
+
 	return 0;
 }
 
diff --git a/arch/powerpc/perf/hv-gpci.h b/arch/powerpc/perf/hv-gpci.h
index c72020912dea..ff76bc010823 100644
--- a/arch/powerpc/perf/hv-gpci.h
+++ b/arch/powerpc/perf/hv-gpci.h
@@ -23,6 +23,12 @@ enum {
 	HV_GPCI_CM_LAB = (1 << 5)
 };
 
+/* Counter request value to retrieve system information */
+#define PROCESSOR_BUS_TOPOLOGY 0XD0
+
+/* Interface attribute array index to store system information */
+#define INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR	6
+
 #define REQUEST_FILE "../hv-gpci-requests.h"
 #define NAME_LOWER hv_gpci
 #define NAME_UPPER HV_GPCI
-- 
2.35.3

[PATCH 02/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_bus_topology sysfs interface file

[Kajol Jain]

Add details of the new hv-gpci interface file called
"processor_bus_topology" in the ABI documentation.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci    | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index 12e2bf92783f..6d633167268e 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -80,3 +80,32 @@ Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
 Description:	read only
 		This sysfs file exposes the cpumask which is designated to make
 		HCALLs to retrieve hv-gpci pmu event counter data.
+
+What:		/sys/devices/hv_gpci/interface/processor_bus_topology
+Date:		June 2023
+Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:	admin read only
+		This sysfs file exposes the system topology information by making HCALL
+		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
+		PROCESSOR_BUS_TOPOLOGY(0xD0).
+		* This sysfs file is only be created for power10 and above platforms.
+		* User need root access to read data from this sysfs file.
+		* Incase the HCALL fails with hardware/permission issue, or the support for
+		  PROCESSOR_BUS_TOPOLOGY counter request value removed, this sysfs file still be
+		  created and give error when reading it.
+		* The end user reading this sysfs file need to decode sysfs file data as per
+		  underneath platform/firmware.
+
+		Possible error codes while reading this sysfs file:
+
+		* "-EPERM" : Partition is not permitted to retrieve performance information,
+			    required to set "Enable Performance Information Collection" option.
+
+		* "-EOPNOTSUPP" : Requested system information is not available for the firmware
+				  level and platform.
+
+		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
+			   or because of some hardware error. Refer getPerfCountInfo documentation for
+			   more information.
+
+		* "-EFBIG" : System information exceeds PAGE_SIZE.
-- 
2.35.3

[PATCH 03/10] powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show processor config information

[Kajol Jain]

The hcall H_GET_PERF_COUNTER_INFO with counter request value as
PROCESSOR_CONFIG(0X90), can be used to get the system
processor configuration information. To expose the system
processor config information, patch adds sysfs file called
"processor_config" to the "/sys/devices/hv_gpci/interface/"
of hv_gpci pmu driver.

Add macro for PROCESSOR_CONFIG counter request value in hv-gpci.h file.
Also add a new function called "sysinfo_device_attr_create",
which will create and add required device attribute to the
interface_attrs array.

The processor_config sysfs file is only available for power10
and above platforms. Add a new macro called
INTERFACE_PROCESSOR_CONFIG_ATTR, which points to the index of
NULL placefolder, for processor_config attribute in the interface_attrs
array. Also add macro INTERFACE_NULL_ATTR which points to index of NULL
attribute in interface_attrs array.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 110 +++++++++++++++++++++++++++++++++---
 arch/powerpc/perf/hv-gpci.h |   5 +-
 2 files changed, 107 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index bca24725699e..c9fe74373e5f 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -237,6 +237,72 @@ static ssize_t processor_bus_topology_show(struct device *dev, struct device_att
 	return ret;
 }
 
+static ssize_t processor_config_show(struct device *dev, struct device_attribute *attr,
+					char *buf)
+{
+	struct hv_gpci_request_buffer *arg;
+	unsigned long ret;
+	size_t n = 0;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * Pass the counter request value 0x90 corresponds to request
+	 * type 'Processor_config', to retrieve
+	 * the system processor information.
+	 * starting_index value implies the starting hardware
+	 * processor index.
+	 */
+	ret = systeminfo_gpci_request(PROCESSOR_CONFIG, 0, 0, buf, &n, arg);
+
+	if (!ret)
+		return n;
+
+	if (ret != H_PARAMETER)
+		goto out;
+
+	/*
+	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL', which
+	 * implies that buffer can't accommodate all information, and a partial buffer
+	 * returned. To handle that, we need to take subsequent requests
+	 * with next starting index to retrieve additional (missing) data.
+	 * Below loop do subsequent hcalls with next starting index and add it
+	 * to buffer util we get all the information.
+	 */
+	while (ret == H_PARAMETER) {
+		int returned_values = be16_to_cpu(arg->params.returned_values);
+		int elementsize = be16_to_cpu(arg->params.cv_element_size);
+		int last_element = (returned_values - 1) * elementsize;
+
+		/*
+		 * Since the starting index is part of counter_value
+		 * buffer elements, use the starting index value in the last
+		 * element and add 1 to subsequent hcalls.
+		 */
+		u32 starting_index = arg->bytes[last_element + 3] +
+				(arg->bytes[last_element + 2] << 8) +
+				(arg->bytes[last_element + 1] << 16) +
+				(arg->bytes[last_element] << 24) + 1;
+
+		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+		ret = systeminfo_gpci_request(PROCESSOR_CONFIG, starting_index, 0, buf, &n, arg);
+
+		if (!ret)
+			return n;
+
+		if (ret != H_PARAMETER)
+			goto out;
+	}
+
+	return n;
+
+out:
+	put_cpu_var(hv_gpci_reqb);
+	return ret;
+}
+
 static DEVICE_ATTR_RO(kernel_version);
 static DEVICE_ATTR_RO(cpumask);
 
@@ -258,6 +324,11 @@ static struct attribute *interface_attrs[] = {
 	 * attribute, set in init function if applicable.
 	 */
 	NULL,
+	/*
+	 * This NULL is a placeholder for the processor_config
+	 * attribute, set in init function if applicable.
+	 */
+	NULL,
 	NULL,
 };
 
@@ -463,21 +534,46 @@ static int hv_gpci_cpu_hotplug_init(void)
 			  ppc_hv_gpci_cpu_offline);
 }
 
-static void add_sysinfo_interface_files(void)
+static void sysinfo_device_attr_create(int sysinfo_interface_group_index)
 {
-	struct device_attribute *attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	struct device_attribute *attr;
 
+	if (sysinfo_interface_group_index < INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR ||
+			sysinfo_interface_group_index >= INTERFACE_NULL_ATTR) {
+		pr_info("Wrong interface group index for system information\n");
+		return;
+	}
+
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 	if (!attr) {
-		pr_info("Memory allocation failed for processor_bug_topology interface file\n");
+		pr_info("Mem allocation failed, sysinfo index:%d\n", sysinfo_interface_group_index);
 		return;
 	}
 
-	/* Add processor_bus_topology attribute in the interface_attrs attribute array */
 	sysfs_attr_init(&attr->attr);
-	attr->attr.name = "processor_bug_topology";
+
+	switch (sysinfo_interface_group_index) {
+	case INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR:
+		attr->attr.name = "processor_bug_topology";
+		attr->show = processor_bus_topology_show;
+	break;
+	case INTERFACE_PROCESSOR_CONFIG_ATTR:
+		attr->attr.name = "processor_config";
+		attr->show = processor_config_show;
+	break;
+	}
+
 	attr->attr.mode = 0444;
-	attr->show = processor_bus_topology_show;
-	interface_attrs[INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR] = &attr->attr;
+	interface_attrs[sysinfo_interface_group_index] = &attr->attr;
+}
+
+static void add_sysinfo_interface_files(void)
+{
+	/* Add processor_bus_topology attribute in the interface_attrs attribute array */
+	sysinfo_device_attr_create(INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR);
+
+	/* Add processor_config attribute in the interface_attrs attribute array */
+	sysinfo_device_attr_create(INTERFACE_PROCESSOR_CONFIG_ATTR);
 }
 
 static int hv_gpci_init(void)
diff --git a/arch/powerpc/perf/hv-gpci.h b/arch/powerpc/perf/hv-gpci.h
index ff76bc010823..0d324a7c684b 100644
--- a/arch/powerpc/perf/hv-gpci.h
+++ b/arch/powerpc/perf/hv-gpci.h
@@ -24,10 +24,13 @@ enum {
 };
 
 /* Counter request value to retrieve system information */
-#define PROCESSOR_BUS_TOPOLOGY 0XD0
+#define PROCESSOR_BUS_TOPOLOGY	0XD0
+#define PROCESSOR_CONFIG	0X90
 
 /* Interface attribute array index to store system information */
 #define INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR	6
+#define INTERFACE_PROCESSOR_CONFIG_ATTR		7
+#define INTERFACE_NULL_ATTR			8
 
 #define REQUEST_FILE "../hv-gpci-requests.h"
 #define NAME_LOWER hv_gpci
-- 
2.35.3

[PATCH 04/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_config sysfs interface file

[Kajol Jain]

Add details of the new hv-gpci interface file called
"processor_config" in the ABI documentation.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index 6d633167268e..003d94afbbcd 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -109,3 +109,18 @@ Description:	admin read only
 			   more information.
 
 		* "-EFBIG" : System information exceeds PAGE_SIZE.
+
+What:		/sys/devices/hv_gpci/interface/processor_config
+Date:		June 2023
+Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:	admin read only
+		This sysfs file exposes the system topology information by making HCALL
+		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
+		PROCESSOR_CONFIG(0x90).
+		* This sysfs file is only be created for power10 and above platforms.
+		* User need root access to read data from this sysfs file.
+		* Incase the HCALL fails with hardware/permission issue, or the support for
+		  PROCESSOR_CONFIG counter request value removed, this sysfs file still be
+		  created and give error when reading it.
+		* The end user reading this sysfs file need to decode sysfs file data as per
+		  underneath platform/firmware.
-- 
2.35.3

[PATCH 05/10] powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity domain via virtual processor information

[Kajol Jain]

The hcall H_GET_PERF_COUNTER_INFO with counter request value as
AFFINITY_DOMAIN_INFORMATION_BY_VIRTUAL_PROCESSOR(0XA0), can be used to get
the system affinity domain via virtual processor information. To expose
the system affinity domain via virtual processor information, patch adds
sysfs file called "affinity_domain_via_virtual_processor" to the
"/sys/devices/hv_gpci/interface/" of hv_gpci pmu driver.

Add macro for AFFINITY_DOMAIN_VIA_VP, which points to counter request value
for "affinity_domain_via_virtual_processor" in hv-gpci.h file.

The affinity_domain_via_virtual_processor sysfs file is only available for
power10 and above platforms. Add a macro called
INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR, which points to the index of NULL
placeholder, for affinity_domain_via_virtual_processor attribute in
interface_attrs array. Also updated the value of INTERFACE_NULL_ATTR macro
in hv-gpci.h file.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 84 +++++++++++++++++++++++++++++++++++++
 arch/powerpc/perf/hv-gpci.h |  4 +-
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index c9fe74373e5f..cac726f06221 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -303,6 +303,75 @@ static ssize_t processor_config_show(struct device *dev, struct device_attribute
 	return ret;
 }
 
+static ssize_t affinity_domain_via_virtual_processor_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct hv_gpci_request_buffer *arg;
+	unsigned long ret;
+	size_t n = 0;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * Pass the counter request 0xA0 corresponds to request
+	 * type 'Affinity_domain_information_by_virutal_processor',
+	 * to retrieve the system affinity domain information.
+	 * starting_index value refers to the starting hardware
+	 * processor index.
+	 */
+	ret = systeminfo_gpci_request(AFFINITY_DOMAIN_VIA_VP, 0, 0, buf, &n, arg);
+
+	if (!ret)
+		return n;
+
+	if (ret != H_PARAMETER)
+		goto out;
+
+	/*
+	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL', which
+	 * implies that buffer can't accommodate all information, and a partial buffer
+	 * returned. To handle that, we need to take subsequent requests
+	 * with next secondary index to retrieve additional (missing) data.
+	 * Below loop do subsequent hcalls with next secondary index and add it
+	 * to buffer util we get all the information.
+	 */
+	while (ret == H_PARAMETER) {
+		int returned_values = be16_to_cpu(arg->params.returned_values);
+		int elementsize = be16_to_cpu(arg->params.cv_element_size);
+		int last_element = (returned_values - 1) * elementsize;
+
+		/*
+		 * Since the starting index and secondary index type is part of the
+		 * counter_value buffer elements, use the starting index value in the
+		 * last array element as subsequent starting index, and use secondary index
+		 * value in the last array element plus 1 as subsequent secondary index.
+		 * For counter request '0xA0', starting index points to partition id
+		 * and secondary index points to corresponding virtual processor index.
+		 */
+		u32 starting_index = arg->bytes[last_element + 1] + (arg->bytes[last_element] << 8);
+		u16 secondary_index = arg->bytes[last_element + 3] +
+				(arg->bytes[last_element + 2] << 8) + 1;
+
+		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+		ret = systeminfo_gpci_request(AFFINITY_DOMAIN_VIA_VP, starting_index,
+					secondary_index, buf, &n, arg);
+
+		if (!ret)
+			return n;
+
+		if (ret != H_PARAMETER)
+			goto out;
+	}
+
+	return n;
+
+out:
+	put_cpu_var(hv_gpci_reqb);
+	return ret;
+}
+
 static DEVICE_ATTR_RO(kernel_version);
 static DEVICE_ATTR_RO(cpumask);
 
@@ -329,6 +398,11 @@ static struct attribute *interface_attrs[] = {
 	 * attribute, set in init function if applicable.
 	 */
 	NULL,
+	/*
+	 * This NULL is a placeholder for the affinity_domain_via_virtual_processor
+	 * attribute, set in init function if applicable.
+	 */
+	NULL,
 	NULL,
 };
 
@@ -561,6 +635,10 @@ static void sysinfo_device_attr_create(int sysinfo_interface_group_index)
 		attr->attr.name = "processor_config";
 		attr->show = processor_config_show;
 	break;
+	case INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR:
+		attr->attr.name = "affinity_domain_via_virtual_processor";
+		attr->show = affinity_domain_via_virtual_processor_show;
+	break;
 	}
 
 	attr->attr.mode = 0444;
@@ -574,6 +652,12 @@ static void add_sysinfo_interface_files(void)
 
 	/* Add processor_config attribute in the interface_attrs attribute array */
 	sysinfo_device_attr_create(INTERFACE_PROCESSOR_CONFIG_ATTR);
+
+	/*
+	 * Add affinity_domain_via_virtual_processor attribute in the
+	 * interface_attrs attribute array
+	 */
+	sysinfo_device_attr_create(INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR);
 }
 
 static int hv_gpci_init(void)
diff --git a/arch/powerpc/perf/hv-gpci.h b/arch/powerpc/perf/hv-gpci.h
index 0d324a7c684b..c88599fbcaa5 100644
--- a/arch/powerpc/perf/hv-gpci.h
+++ b/arch/powerpc/perf/hv-gpci.h
@@ -26,11 +26,13 @@ enum {
 /* Counter request value to retrieve system information */
 #define PROCESSOR_BUS_TOPOLOGY	0XD0
 #define PROCESSOR_CONFIG	0X90
+#define AFFINITY_DOMAIN_VIA_VP	0xA0 /* affinity domain via virtual processor */
 
 /* Interface attribute array index to store system information */
 #define INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR	6
 #define INTERFACE_PROCESSOR_CONFIG_ATTR		7
-#define INTERFACE_NULL_ATTR			8
+#define INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR	8
+#define INTERFACE_NULL_ATTR			9
 
 #define REQUEST_FILE "../hv-gpci-requests.h"
 #define NAME_LOWER hv_gpci
-- 
2.35.3

[PATCH 06/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document affinity_domain_via_virtual_processor sysfs interface file

[Kajol Jain]

Add details of the new hv-gpci interface file called
"affinity_domain_via_virtual_processor" in the ABI documentation.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index 003d94afbbcd..d8862808c955 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -124,3 +124,18 @@ Description:	admin read only
 		  created and give error when reading it.
 		* The end user reading this sysfs file need to decode sysfs file data as per
 		  underneath platform/firmware.
+
+What:		/sys/devices/hv_gpci/interface/affinity_domain_via_virtual_processor
+Date:		June 2023
+Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:	admin read only
+		This sysfs file exposes the system topology information by making HCALL
+		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
+		AFFINITY_DOMAIN_INFORMATION_BY_VIRTUAL_PROCESSOR(0xA0).
+		* This sysfs file is only be created for power10 and above platforms.
+		* User need root access to read data from this sysfs file.
+		* Incase the HCALL fails with hardware/permission issue, or the support for
+		  AFFINITY_DOMAIN_INFORMATION_BY_VIRTUAL_PROCESSOR counter request value
+		  removed, this sysfs file still be created and give error when reading it.
+		* The end user reading this sysfs file need to decode sysfs file data as per
+		  underneath platform/firmware.
-- 
2.35.3

[PATCH 07/10] powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity domain via domain information

[Kajol Jain]

The hcall H_GET_PERF_COUNTER_INFO with counter request value as
AFFINITY_DOMAIN_INFORMATION_BY_DOMAIN(0XB0), can be used to get
the system affinity domain via domain information. To expose the system
affinity domain via domain information, patch adds sysfs file called
"affinity_domain_via_domain" to the "/sys/devices/hv_gpci/interface/"
of hv_gpci pmu driver.

Add macro for AFFINITY_DOMAIN_VIA_DOM, which points to the counter
request value for "affinity_domain_via_domain" in hv-gpci.h file.

The affinity_domain_via_domain sysfs file is only available for power10
and above platforms. Add a macro called
INTERFACE_AFFINITY_DOMAIN_VIA_DOM_ATTR, which points to the index of NULL
placeholder, for affinity_domain_via_domain attribute in interface_attrs
array. Also updated the value of INTERFACE_NULL_ATTR macro in hv-gpci.h
file.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 77 +++++++++++++++++++++++++++++++++++++
 arch/powerpc/perf/hv-gpci.h |  4 +-
 2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index cac726f06221..b18f6f2d15b0 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -372,6 +372,71 @@ static ssize_t affinity_domain_via_virtual_processor_show(struct device *dev,
 	return ret;
 }
 
+static ssize_t affinity_domain_via_domain_show(struct device *dev, struct device_attribute *attr,
+						char *buf)
+{
+	struct hv_gpci_request_buffer *arg;
+	unsigned long ret;
+	size_t n = 0;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * Pass the counter request 0xB0 corresponds to request
+	 * type 'Affinity_domain_information_by_domain',
+	 * to retrieve the system affinity domain information.
+	 * starting_index value refers to the starting hardware
+	 * processor index.
+	 */
+	ret = systeminfo_gpci_request(AFFINITY_DOMAIN_VIA_DOM, 0, 0, buf, &n, arg);
+
+	if (!ret)
+		return n;
+
+	if (ret != H_PARAMETER)
+		goto out;
+
+	/*
+	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL', which
+	 * implies that buffer can't accommodate all information, and a partial buffer
+	 * returned. To handle that, we need to take subsequent requests
+	 * with next starting index to retrieve additional (missing) data.
+	 * Below loop do subsequent hcalls with next starting index and add it
+	 * to buffer util we get all the information.
+	 */
+	while (ret == H_PARAMETER) {
+		int returned_values = be16_to_cpu(arg->params.returned_values);
+		int elementsize = be16_to_cpu(arg->params.cv_element_size);
+		int last_element = (returned_values - 1) * elementsize;
+
+		/*
+		 * Since the starting index value is part of counter_value
+		 * buffer elements, use the starting index value in the last
+		 * element and add 1 to make subsequent hcalls.
+		 */
+		u32 starting_index = arg->bytes[last_element + 1] +
+			(arg->bytes[last_element] << 8) + 1;
+
+		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+		ret = systeminfo_gpci_request(AFFINITY_DOMAIN_VIA_DOM,
+					starting_index, 0, buf, &n, arg);
+
+		if (!ret)
+			return n;
+
+		if (ret != H_PARAMETER)
+			goto out;
+	}
+
+	return n;
+
+out:
+	put_cpu_var(hv_gpci_reqb);
+	return ret;
+}
+
 static DEVICE_ATTR_RO(kernel_version);
 static DEVICE_ATTR_RO(cpumask);
 
@@ -403,6 +468,11 @@ static struct attribute *interface_attrs[] = {
 	 * attribute, set in init function if applicable.
 	 */
 	NULL,
+	/*
+	 * This NULL is a placeholder for the affinity_domain_via_domain
+	 * attribute, set in init function if applicable.
+	 */
+	NULL,
 	NULL,
 };
 
@@ -639,6 +709,10 @@ static void sysinfo_device_attr_create(int sysinfo_interface_group_index)
 		attr->attr.name = "affinity_domain_via_virtual_processor";
 		attr->show = affinity_domain_via_virtual_processor_show;
 	break;
+	case INTERFACE_AFFINITY_DOMAIN_VIA_DOM_ATTR:
+		attr->attr.name = "affinity_domain_via_domain";
+		attr->show = affinity_domain_via_domain_show;
+	break;
 	}
 
 	attr->attr.mode = 0444;
@@ -658,6 +732,9 @@ static void add_sysinfo_interface_files(void)
 	 * interface_attrs attribute array
 	 */
 	sysinfo_device_attr_create(INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR);
+
+	/* Add affinity_domain_via_domain attribute in the interface_attrs attribute array */
+	sysinfo_device_attr_create(INTERFACE_AFFINITY_DOMAIN_VIA_DOM_ATTR);
 }
 
 static int hv_gpci_init(void)
diff --git a/arch/powerpc/perf/hv-gpci.h b/arch/powerpc/perf/hv-gpci.h
index c88599fbcaa5..f01c4716ac33 100644
--- a/arch/powerpc/perf/hv-gpci.h
+++ b/arch/powerpc/perf/hv-gpci.h
@@ -27,12 +27,14 @@ enum {
 #define PROCESSOR_BUS_TOPOLOGY	0XD0
 #define PROCESSOR_CONFIG	0X90
 #define AFFINITY_DOMAIN_VIA_VP	0xA0 /* affinity domain via virtual processor */
+#define AFFINITY_DOMAIN_VIA_DOM	0xB0 /* affinity domain via domain */
 
 /* Interface attribute array index to store system information */
 #define INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR	6
 #define INTERFACE_PROCESSOR_CONFIG_ATTR		7
 #define INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR	8
-#define INTERFACE_NULL_ATTR			9
+#define INTERFACE_AFFINITY_DOMAIN_VIA_DOM_ATTR	9
+#define INTERFACE_NULL_ATTR			10
 
 #define REQUEST_FILE "../hv-gpci-requests.h"
 #define NAME_LOWER hv_gpci
-- 
2.35.3

[PATCH 08/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document affinity_domain_via_domain sysfs interface file

[Kajol Jain]

Add details of the new hv-gpci interface file called
"affinity_domain_via_domain" in the ABI documentation.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index d8862808c955..1a5636ed3a4b 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -139,3 +139,18 @@ Description:	admin read only
 		  removed, this sysfs file still be created and give error when reading it.
 		* The end user reading this sysfs file need to decode sysfs file data as per
 		  underneath platform/firmware.
+
+What:		/sys/devices/hv_gpci/interface/affinity_domain_via_domain
+Date:		June 2023
+Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:	admin read only
+		This sysfs file exposes the system topology information by making HCALL
+		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
+		AFFINITY_DOMAIN_INFORMATION_BY_DOMAIN(0xB0).
+		* This sysfs file is only be created for power10 and above platforms.
+		* User need root access to read data from this sysfs file.
+		* Incase the HCALL fails with hardware/permission issue, or the support for
+		  AFFINITY_DOMAIN_INFORMATION_BY_DOMAIN counter request value
+		  removed, this sysfs file still be created and give error when reading it.
+		* The end user reading this sysfs file need to decode sysfs file data as per
+		  underneath platform/firmware.
-- 
2.35.3

[PATCH 09/10] powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity domain via partition information

[Kajol Jain]

The hcall H_GET_PERF_COUNTER_INFO with counter request value as
AFFINITY_DOMAIN_INFORMATION_BY_PARTITION(0XB1), can be used to get
the system affinity domain via partition information. To expose the system
affinity domain via partition information, patch adds sysfs file called
"affinity_domain_via_partition" to the "/sys/devices/hv_gpci/interface/"
of hv_gpci pmu driver.

Add macro AFFINITY_DOMAIN_VIA_PAR, which points to the counter request
value for "affinity_domain_via_partition", in hv-gpci.h file. Also add a
new function called "affinity_domain_via_partition_result_parse" to parse
the hcall result and store it in output buffer.

The affinity_domain_via_partition sysfs file is only available for power10
and above platforms. Add a macro called
INTERFACE_AFFINITY_DOMAIN_VIA_PAR_ATTR, which points to the index of NULL
placeholder, for affinity_domain_via_partition attribute in
interface_attrs array. Also updated the value of INTERFACE_NULL_ATTR
macro in hv-gpci.h file.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 164 ++++++++++++++++++++++++++++++++++++
 arch/powerpc/perf/hv-gpci.h |   4 +-
 2 files changed, 167 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index b18f6f2d15b0..6e57c6065010 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -437,6 +437,158 @@ static ssize_t affinity_domain_via_domain_show(struct device *dev, struct device
 	return ret;
 }
 
+static void affinity_domain_via_partition_result_parse(int returned_values,
+			int element_size, char *buf, size_t *last_element,
+			size_t *n, struct hv_gpci_request_buffer *arg)
+{
+	size_t i = 0, j = 0;
+	size_t k, l, m;
+	uint16_t total_affinity_domain_ele, size_of_each_affinity_domain_ele;
+
+	/*
+	 * hcall H_GET_PERF_COUNTER_INFO populates the 'returned_values'
+	 * to show the total number of counter_value array elements
+	 * returned via hcall.
+	 * Unlike other request types, the data structure returned by this
+	 * request is variable-size. For this counter request type,
+	 * hcall populates 'cv_element_size' corresponds to minimum size of
+	 * the structure returned i.e; the size of the structure with no domain
+	 * information. Below loop go through all counter_value array
+	 * to determine the number and size of each domain array element and
+	 * add it to the output buffer.
+	 */
+	while (i < returned_values) {
+		k = j;
+		for (; k < j + element_size; k++)
+			*n += sprintf(buf + *n,  "%02x", (u8)arg->bytes[k]);
+		*n += sprintf(buf + *n,  "\n");
+
+		total_affinity_domain_ele = (u8)arg->bytes[k - 2] << 8 | (u8)arg->bytes[k - 3];
+		size_of_each_affinity_domain_ele = (u8)arg->bytes[k] << 8 | (u8)arg->bytes[k - 1];
+
+		for (l = 0; l < total_affinity_domain_ele; l++) {
+			for (m = 0; m < size_of_each_affinity_domain_ele; m++) {
+				*n += sprintf(buf + *n,  "%02x", (u8)arg->bytes[k]);
+				k++;
+			}
+			*n += sprintf(buf + *n,  "\n");
+		}
+
+		*n += sprintf(buf + *n,  "\n");
+		i++;
+		j = k;
+	}
+
+	*last_element = k;
+}
+
+static ssize_t affinity_domain_via_partition_show(struct device *dev, struct device_attribute *attr,
+							char *buf)
+{
+	struct hv_gpci_request_buffer *arg;
+	unsigned long ret;
+	size_t n = 0;
+	size_t last_element = 0;
+	u32 starting_index;
+
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * Pass the counter request value 0xB1 corresponds to counter request
+	 * type 'Affinity_domain_information_by_partition',
+	 * to retrieve the system affinity domain by partition information.
+	 * starting_index value refers to the starting hardware
+	 * processor index.
+	 */
+	arg->params.counter_request = cpu_to_be32(AFFINITY_DOMAIN_VIA_PAR);
+	arg->params.starting_index = cpu_to_be32(0);
+
+	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+
+	if (!ret)
+		goto parse_result;
+
+	/*
+	 * ret value as 'H_PARAMETER' implies that the current buffer size
+	 * can't accommodate all the information, and a partial buffer
+	 * returned. To handle that, we need to make subsequent requests
+	 * with next starting index to retrieve additional (missing) data.
+	 * Below loop do subsequent hcalls with next starting index and add it
+	 * to buffer util we get all the information.
+	 */
+	while (ret == H_PARAMETER) {
+		affinity_domain_via_partition_result_parse(
+			be16_to_cpu(arg->params.returned_values) - 1,
+			be16_to_cpu(arg->params.cv_element_size), buf,
+			&last_element, &n, arg);
+
+		if (n >= PAGE_SIZE) {
+			put_cpu_var(hv_gpci_reqb);
+			pr_debug("System information exceeds PAGE_SIZE\n");
+			return -EFBIG;
+		}
+
+		/*
+		 * Since the starting index value is part of counter_value
+		 * buffer elements, use the starting_index value in the last
+		 * element and add 1 to make subsequent hcalls.
+		 */
+		starting_index = (u8)arg->bytes[last_element] << 8 |
+				(u8)arg->bytes[last_element + 1];
+
+		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+		arg->params.counter_request = cpu_to_be32(AFFINITY_DOMAIN_VIA_PAR);
+		arg->params.starting_index = cpu_to_be32(starting_index);
+
+		ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+				virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+
+		if (ret && (ret != H_PARAMETER))
+			goto out;
+	}
+
+parse_result:
+	affinity_domain_via_partition_result_parse(
+		be16_to_cpu(arg->params.returned_values),
+		be16_to_cpu(arg->params.cv_element_size),
+		buf, &last_element, &n, arg);
+
+	put_cpu_var(hv_gpci_reqb);
+	return n;
+
+out:
+	put_cpu_var(hv_gpci_reqb);
+
+	/*
+	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL',
+	 * which means that the current buffer size cannot accommodate
+	 * all the information and a partial buffer returned.
+	 * hcall fails incase of ret value other than H_SUCCESS or H_PARAMETER.
+	 *
+	 * ret value as H_AUTHORITY implies that partition is not permitted to retrieve
+	 * performance information, and required to set
+	 * "Enable Performance Information Collection" option.
+	 */
+	if (ret == H_AUTHORITY)
+		return -EPERM;
+
+	/*
+	 * ret value as H_NOT_AVAILABLE implies that requested system information is
+	 * not available for the firmware level and platform.
+	 */
+	if (ret == H_NOT_AVAILABLE)
+		return -EOPNOTSUPP;
+
+	/*
+	 * hcall can fail with other possible ret value like H_PRIVILEGE/H_HARDWARE
+	 * because of invalid buffer-length/address or due to some hardware
+	 * error.
+	 */
+	return -EIO;
+}
+
 static DEVICE_ATTR_RO(kernel_version);
 static DEVICE_ATTR_RO(cpumask);
 
@@ -473,6 +625,11 @@ static struct attribute *interface_attrs[] = {
 	 * attribute, set in init function if applicable.
 	 */
 	NULL,
+	/*
+	 * This NULL is a placeholder for the affinity_domain_via_partition
+	 * attribute, set in init function if applicable.
+	 */
+	NULL,
 	NULL,
 };
 
@@ -713,6 +870,10 @@ static void sysinfo_device_attr_create(int sysinfo_interface_group_index)
 		attr->attr.name = "affinity_domain_via_domain";
 		attr->show = affinity_domain_via_domain_show;
 	break;
+	case INTERFACE_AFFINITY_DOMAIN_VIA_PAR_ATTR:
+		attr->attr.name = "affinity_domain_via_partition";
+		attr->show = affinity_domain_via_partition_show;
+	break;
 	}
 
 	attr->attr.mode = 0444;
@@ -735,6 +896,9 @@ static void add_sysinfo_interface_files(void)
 
 	/* Add affinity_domain_via_domain attribute in the interface_attrs attribute array */
 	sysinfo_device_attr_create(INTERFACE_AFFINITY_DOMAIN_VIA_DOM_ATTR);
+
+	/* Add affinity_domain_via_partition attribute in the interface_attrs attribute array */
+	sysinfo_device_attr_create(INTERFACE_AFFINITY_DOMAIN_VIA_PAR_ATTR);
 }
 
 static int hv_gpci_init(void)
diff --git a/arch/powerpc/perf/hv-gpci.h b/arch/powerpc/perf/hv-gpci.h
index f01c4716ac33..c293f6c2b66c 100644
--- a/arch/powerpc/perf/hv-gpci.h
+++ b/arch/powerpc/perf/hv-gpci.h
@@ -28,13 +28,15 @@ enum {
 #define PROCESSOR_CONFIG	0X90
 #define AFFINITY_DOMAIN_VIA_VP	0xA0 /* affinity domain via virtual processor */
 #define AFFINITY_DOMAIN_VIA_DOM	0xB0 /* affinity domain via domain */
+#define AFFINITY_DOMAIN_VIA_PAR	0xB1 /* affinity domain via partition */
 
 /* Interface attribute array index to store system information */
 #define INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR	6
 #define INTERFACE_PROCESSOR_CONFIG_ATTR		7
 #define INTERFACE_AFFINITY_DOMAIN_VIA_VP_ATTR	8
 #define INTERFACE_AFFINITY_DOMAIN_VIA_DOM_ATTR	9
-#define INTERFACE_NULL_ATTR			10
+#define INTERFACE_AFFINITY_DOMAIN_VIA_PAR_ATTR	10
+#define INTERFACE_NULL_ATTR			11
 
 #define REQUEST_FILE "../hv-gpci-requests.h"
 #define NAME_LOWER hv_gpci
-- 
2.35.3

[PATCH 10/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document affinity_domain_via_partition sysfs interface file

[Kajol Jain]

Add details of the new hv-gpci interface file called
"affinity_domain_via_partition" in the ABI documentation.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 .../sysfs-bus-event_source-devices-hv_gpci        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index 1a5636ed3a4b..6bca74cf3220 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -154,3 +154,18 @@ Description:	admin read only
 		  removed, this sysfs file still be created and give error when reading it.
 		* The end user reading this sysfs file need to decode sysfs file data as per
 		  underneath platform/firmware.
+
+What:		/sys/devices/hv_gpci/interface/affinity_domain_via_partition
+Date:		June 2023
+Contact:	Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description:	admin read only
+		This sysfs file exposes the system topology information by making HCALL
+		H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request value
+		AFFINITY_DOMAIN_INFORMATION_BY_PARTITION(0xB1).
+		* This sysfs file is only be created for power10 and above platforms.
+		* User need root access to read data from this sysfs file.
+		* Incase the HCALL fails with hardware/permission issue, or the support for
+		  AFFINITY_DOMAIN_INFORMATION_BY_PARTITION counter request value
+		  removed, this sysfs file still be created and give error when reading it.
+		* The end user reading this sysfs file need to decode sysfs file data as per
+		  underneath platform/firmware.
-- 
2.35.3