[PATCH v2 00/10] Add sysfs interface files to hv_gpci device to expose system information

[PATCH v2 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.

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

Changelog:
v1 -> v2
-> Incase the HCALL fails with errors that can be resolve during runtime,
   then only add sysinfo interface attributes to the interface_attrs
   attribute array. Even if one of the counter request value HCALL fails,
   don't add any sysinfo attribute to the interface_attrs attribute array.
   Add the code changes to make sure sysinfo interface added only when all
   the requirements met as suggested by Michael Ellerman.
-> Make changes in documentation, adds detail of errors type
   which can be resolved at runtime as suggested by Michael Ellerman.
-> Add new enum and sysinfo_counter_request array to get required
   counter request value in hv-gpci.c file.
-> Move the macros for interface attribute array index to hv-gpci.c, as
   these macros currently only used in hv-gpci.c file

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    | 160 +++++
 arch/powerpc/perf/hv-gpci.c                   | 640 +++++++++++++++++-
 2 files changed, 798 insertions(+), 2 deletions(-)

-- 
2.31.1

[PATCH v2 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.c 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.c
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 | 184 +++++++++++++++++++++++++++++++++++-
 1 file changed, 182 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 7ff8ff3509f5..225f148f75fd 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);
 }
 
+/* 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
+
+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;
+
+	/*
+	 * 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 +463,44 @@ static int hv_gpci_cpu_hotplug_init(void)
 			  ppc_hv_gpci_cpu_offline);
 }
 
+static void add_sysinfo_interface_files(void)
+{
+	struct device_attribute *attr = NULL;
+	unsigned long ret;
+	struct hv_gpci_request_buffer *arg;
+
+	/* Check for counter request type PROCESSOR_BUS_TOPOLOGY support */
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	arg->params.counter_request = cpu_to_be32(PROCESSOR_BUS_TOPOLOGY);
+
+	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+
+	put_cpu_var(hv_gpci_reqb);
+
+	/*
+	 * Add processor_bus_topology attribute in the interface_attrs
+	 * attribute array, only for valid return types.
+	 */
+	if (!ret || ret == H_AUTHORITY || ret == H_PARAMETER) {
+		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+
+		if (!attr) {
+			pr_info("Memory allocation failed for sysinfo interface files\n");
+			return;
+		}
+
+		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;
+	} else
+		pr_devel("hcall failed, with error: 0x%lx\n", ret);
+}
+
 static int hv_gpci_init(void)
 {
 	int r;
@@ -388,6 +564,10 @@ 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;
 }
 
-- 
2.31.1

[PATCH v2 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    | 32 +++++++++++++++++++
 1 file changed, 32 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..2eeeab9a20fa 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 +80,35 @@ 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:		July 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 will be created only for power10 and above platforms.
+
+		* User needs root privileges to read data from this sysfs file.
+
+		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
+		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
+
+		  HCALL with return error type "H_AUTHORITY", can be resolved during
+		  runtime by setting "Enable Performance Information Collection" option.
+
+		* The end user reading this sysfs file must decode the content as per
+		  underlying 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.
+
+		* "-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.
-- 
2.31.1

[PATCH v2 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 enum and sysinfo_counter_request array to get required
counter request value in hv-gpci.c file.
Also add a new function called "sysinfo_device_attr_create",
which will create and return required device attribute to the
add_sysinfo_interface_files function.

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 | 168 ++++++++++++++++++++++++++++++++----
 1 file changed, 153 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 225f148f75fd..c74076d3c7a7 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -102,11 +102,21 @@ static ssize_t cpumask_show(struct device *dev,
 	return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);
 }
 
-/* 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 INTERFACE_PROCESSOR_CONFIG_ATTR		7
+#define INTERFACE_NULL_ATTR			8
+
+/* Counter request value to retrieve system information */
+enum {
+	PROCESSOR_BUS_TOPOLOGY,
+	PROCESSOR_CONFIG
+};
+
+static int sysinfo_counter_request[] = {
+	[PROCESSOR_BUS_TOPOLOGY] = 0xD0,
+	[PROCESSOR_CONFIG] = 0x90,
+};
 
 static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
 
@@ -187,7 +197,8 @@ static ssize_t processor_bus_topology_show(struct device *dev, struct device_att
 	 * starting_index value implies the starting hardware
 	 * chip id.
 	 */
-	ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, 0, 0, buf, &n, arg);
+	ret = systeminfo_gpci_request(sysinfo_counter_request[PROCESSOR_BUS_TOPOLOGY],
+			0, 0, buf, &n, arg);
 
 	if (!ret)
 		return n;
@@ -220,8 +231,76 @@ static ssize_t processor_bus_topology_show(struct device *dev, struct device_att
 
 		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
 
-		ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, starting_index,
-				0, buf, &n, arg);
+		ret = systeminfo_gpci_request(sysinfo_counter_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 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(sysinfo_counter_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(sysinfo_counter_request[PROCESSOR_CONFIG],
+				starting_index, 0, buf, &n, arg);
 
 		if (!ret)
 			return n;
@@ -258,6 +337,11 @@ 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,
 };
 
@@ -463,17 +547,24 @@ static int hv_gpci_cpu_hotplug_init(void)
 			  ppc_hv_gpci_cpu_offline);
 }
 
-static void add_sysinfo_interface_files(void)
+static struct device_attribute *sysinfo_device_attr_create(int
+		sysinfo_interface_group_index, u32 req)
 {
 	struct device_attribute *attr = NULL;
 	unsigned long ret;
 	struct hv_gpci_request_buffer *arg;
 
-	/* Check for counter request type PROCESSOR_BUS_TOPOLOGY support */
+	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 NULL;
+	}
+
+	/* Check for given counter request value support */
 	arg = (void *)get_cpu_var(hv_gpci_reqb);
 	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
 
-	arg->params.counter_request = cpu_to_be32(PROCESSOR_BUS_TOPOLOGY);
+	arg->params.counter_request = cpu_to_be32(req);
 
 	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
 			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
@@ -481,24 +572,71 @@ static void add_sysinfo_interface_files(void)
 	put_cpu_var(hv_gpci_reqb);
 
 	/*
-	 * Add processor_bus_topology attribute in the interface_attrs
+	 * Add given counter request value attribute in the interface_attrs
 	 * attribute array, only for valid return types.
 	 */
 	if (!ret || ret == H_AUTHORITY || ret == H_PARAMETER) {
 		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 
 		if (!attr) {
-			pr_info("Memory allocation failed for sysinfo interface files\n");
-			return;
+			pr_info("Mem allocation failed, for sysinfo interface file");
+			return NULL;
 		}
 
 		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;
+
+		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;
+		}
 	} else
 		pr_devel("hcall failed, with error: 0x%lx\n", ret);
+
+	return attr;
+}
+
+static void add_sysinfo_interface_files(void)
+{
+	int sysfs_count;
+	struct device_attribute *attr[INTERFACE_NULL_ATTR - INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR];
+	int i;
+
+	sysfs_count = INTERFACE_NULL_ATTR - INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR;
+
+	/* Get device attribute for a given counter request value */
+	for (i = 0; i < sysfs_count; i++) {
+		attr[i] = sysinfo_device_attr_create(i + INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR,
+				sysinfo_counter_request[i]);
+
+		if (!attr[i])
+			goto out;
+	}
+
+	/* Add sysinfo interface attributes in the interface_attrs attribute array */
+	for (i = 0; i < sysfs_count; i++)
+		interface_attrs[i + INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR] = &attr[i]->attr;
+
+	return;
+
+out:
+	/*
+	 * The sysinfo interface attributes will be added, only if hcall passed for
+	 * all the counter request values. Free the device attribute array incase
+	 * of any hcall failure.
+	 */
+	if (i > 0) {
+		while (i >= 0) {
+			kfree(attr[i]);
+			i--;
+		}
+	}
 }
 
 static int hv_gpci_init(void)
-- 
2.31.1

[PATCH v2 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    | 32 +++++++++++++++++++
 1 file changed, 32 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 2eeeab9a20fa..aff52dc3b05c 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -112,3 +112,35 @@ Description:	admin read only
 			   more information.
 
 		* "-EFBIG" : System information exceeds PAGE_SIZE.
+
+What:		/sys/devices/hv_gpci/interface/processor_config
+Date:		July 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 will be created only for power10 and above platforms.
+
+		* User needs root privileges to read data from this sysfs file.
+
+		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
+		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
+
+		  HCALL with return error type "H_AUTHORITY", can be resolved during
+		  runtime by setting "Enable Performance Information Collection" option.
+
+		* The end user reading this sysfs file must decode the content as per
+		  underlying 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.
+
+		* "-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.
-- 
2.31.1

[PATCH v2 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.

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.c file.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 86 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 84 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index c74076d3c7a7..68502cb18262 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -105,17 +105,20 @@ static ssize_t cpumask_show(struct device *dev,
 /* 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
 
 /* Counter request value to retrieve system information */
 enum {
 	PROCESSOR_BUS_TOPOLOGY,
-	PROCESSOR_CONFIG
+	PROCESSOR_CONFIG,
+	AFFINITY_DOMAIN_VIA_VP, /* affinity domain via virtual processor */
 };
 
 static int sysinfo_counter_request[] = {
 	[PROCESSOR_BUS_TOPOLOGY] = 0xD0,
 	[PROCESSOR_CONFIG] = 0x90,
+	[AFFINITY_DOMAIN_VIA_VP] = 0xA0,
 };
 
 static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
@@ -316,6 +319,76 @@ 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(sysinfo_counter_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(sysinfo_counter_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);
 
@@ -342,6 +415,11 @@ 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,
 };
 
@@ -595,6 +673,10 @@ static struct device_attribute *sysinfo_device_attr_create(int
 			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;
 		}
 	} else
 		pr_devel("hcall failed, with error: 0x%lx\n", ret);
-- 
2.31.1

[PATCH v2 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    | 32 +++++++++++++++++++
 1 file changed, 32 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 aff52dc3b05c..3b63d66658fe 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -144,3 +144,35 @@ Description:	admin read only
 			   more information.
 
 		* "-EFBIG" : System information exceeds PAGE_SIZE.
+
+What:		/sys/devices/hv_gpci/interface/affinity_domain_via_virtual_processor
+Date:		July 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 will be created only for power10 and above platforms.
+
+		* User needs root privileges to read data from this sysfs file.
+
+		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
+		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
+
+		  HCALL with return error type "H_AUTHORITY", can be resolved during
+		  runtime by setting "Enable Performance Information Collection" option.
+
+		* The end user reading this sysfs file must decode the content as per
+		  underlying 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.
+
+		* "-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.
-- 
2.31.1

[PATCH v2 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 new entry for AFFINITY_DOMAIN_VIA_DOM in sysinfo_counter_request
array, which points to the counter request value
"affinity_domain_via_domain" in hv-gpci.c 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.c
file.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 80 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 79 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 68502cb18262..326b758df7c8 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -106,19 +106,22 @@ static ssize_t cpumask_show(struct device *dev,
 #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
 
 /* Counter request value to retrieve system information */
 enum {
 	PROCESSOR_BUS_TOPOLOGY,
 	PROCESSOR_CONFIG,
 	AFFINITY_DOMAIN_VIA_VP, /* affinity domain via virtual processor */
+	AFFINITY_DOMAIN_VIA_DOM, /* affinity domain via domain */
 };
 
 static int sysinfo_counter_request[] = {
 	[PROCESSOR_BUS_TOPOLOGY] = 0xD0,
 	[PROCESSOR_CONFIG] = 0x90,
 	[AFFINITY_DOMAIN_VIA_VP] = 0xA0,
+	[AFFINITY_DOMAIN_VIA_DOM] = 0xB0,
 };
 
 static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
@@ -389,6 +392,72 @@ 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(sysinfo_counter_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(sysinfo_counter_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);
 
@@ -420,6 +489,11 @@ 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,
 };
 
@@ -677,6 +751,10 @@ static struct device_attribute *sysinfo_device_attr_create(int
 			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;
 		}
 	} else
 		pr_devel("hcall failed, with error: 0x%lx\n", ret);
-- 
2.31.1

[PATCH v2 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    | 32 +++++++++++++++++++
 1 file changed, 32 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 3b63d66658fe..d8e65b93d1f7 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -176,3 +176,35 @@ Description:	admin read only
 			   more information.
 
 		* "-EFBIG" : System information exceeds PAGE_SIZE.
+
+What:		/sys/devices/hv_gpci/interface/affinity_domain_via_domain
+Date:		July 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 will be created only for power10 and above platforms.
+
+		* User needs root privileges to read data from this sysfs file.
+
+		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
+		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
+
+		  HCALL with return error type "H_AUTHORITY", can be resolved during
+		  runtime by setting "Enable Performance Information Collection" option.
+
+		* The end user reading this sysfs file must decode the content as per
+		  underlying 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.
+
+		* "-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.
-- 
2.31.1

[PATCH v2 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 new entry for AFFINITY_DOMAIN_VIA_PAR in sysinfo_counter_request
array, which points to the counter request value
"affinity_domain_via_partition" in hv-gpci.c 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.c file.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/perf/hv-gpci.c | 160 +++++++++++++++++++++++++++++++++++-
 1 file changed, 159 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 326b758df7c8..f2fff166290b 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -107,7 +107,8 @@ static ssize_t cpumask_show(struct device *dev,
 #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
 
 /* Counter request value to retrieve system information */
 enum {
@@ -115,6 +116,7 @@ enum {
 	PROCESSOR_CONFIG,
 	AFFINITY_DOMAIN_VIA_VP, /* affinity domain via virtual processor */
 	AFFINITY_DOMAIN_VIA_DOM, /* affinity domain via domain */
+	AFFINITY_DOMAIN_VIA_PAR, /* affinity domain via partition */
 };
 
 static int sysinfo_counter_request[] = {
@@ -122,6 +124,7 @@ static int sysinfo_counter_request[] = {
 	[PROCESSOR_CONFIG] = 0x90,
 	[AFFINITY_DOMAIN_VIA_VP] = 0xA0,
 	[AFFINITY_DOMAIN_VIA_DOM] = 0xB0,
+	[AFFINITY_DOMAIN_VIA_PAR] = 0xB1,
 };
 
 static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
@@ -458,6 +461,152 @@ 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(sysinfo_counter_request[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(
+				sysinfo_counter_request[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;
+
+	/*
+	 * 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);
 
@@ -494,6 +643,11 @@ 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,
 };
 
@@ -755,6 +909,10 @@ static struct device_attribute *sysinfo_device_attr_create(int
 			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;
 		}
 	} else
 		pr_devel("hcall failed, with error: 0x%lx\n", ret);
-- 
2.31.1

[PATCH v2 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    | 32 +++++++++++++++++++
 1 file changed, 32 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 d8e65b93d1f7..b03b2bd4b081 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -208,3 +208,35 @@ Description:	admin read only
 			   more information.
 
 		* "-EFBIG" : System information exceeds PAGE_SIZE.
+
+What:		/sys/devices/hv_gpci/interface/affinity_domain_via_partition
+Date:		July 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 will be created only for power10 and above platforms.
+
+		* User needs root privileges to read data from this sysfs file.
+
+		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
+		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
+
+		  HCALL with return error type "H_AUTHORITY", can be resolved during
+		  runtime by setting "Enable Performance Information Collection" option.
+
+		* The end user reading this sysfs file must decode the content as per
+		  underlying 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.
+
+		* "-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.
-- 
2.31.1

Re: [PATCH v2 02/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_bus_topology sysfs interface file

[Randy Dunlap]

Hi--

On 7/10/23 02:27, Kajol Jain wrote:
> 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    | 32 +++++++++++++++++++
>  1 file changed, 32 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..2eeeab9a20fa 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 +80,35 @@ 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:		July 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 will be created only for power10 and above platforms.
> +
> +		* User needs root privileges to read data from this sysfs file.
> +
> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",

		                                                                H_SUCCESS

> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.

		            s/and/or/

> +
> +		  HCALL with return error type "H_AUTHORITY", can be resolved during

		                             Drop the comma ^

> +		  runtime by setting "Enable Performance Information Collection" option.
> +
> +		* The end user reading this sysfs file must decode the content as per
> +		  underlying 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.
> +
> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
> +			   or because of some hardware error. Refer getPerfCountInfo documentation for

			                                      Refer to

> +			   more information.
> +
> +		* "-EFBIG" : System information exceeds PAGE_SIZE.

-- 
~Randy

Re: [PATCH v2 04/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_config sysfs interface file

[Randy Dunlap]

Hi--

On 7/10/23 02:27, Kajol Jain wrote:
> 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    | 32 +++++++++++++++++++
>  1 file changed, 32 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 2eeeab9a20fa..aff52dc3b05c 100644
> --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> @@ -112,3 +112,35 @@ Description:	admin read only
>  			   more information.
>  
>  		* "-EFBIG" : System information exceeds PAGE_SIZE.
> +
> +What:		/sys/devices/hv_gpci/interface/processor_config
> +Date:		July 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 will be created only for power10 and above platforms.
> +
> +		* User needs root privileges to read data from this sysfs file.
> +
> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",

		                                                                H_SUCCESS

> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.

		           s/and/or/

> +
> +		  HCALL with return error type "H_AUTHORITY", can be resolved during

		                  Drop the comma:           ^

> +		  runtime by setting "Enable Performance Information Collection" option.
> +
> +		* The end user reading this sysfs file must decode the content as per
> +		  underlying 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.
> +
> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
> +			   or because of some hardware error. Refer getPerfCountInfo documentation for

			                                      Refer to

> +			   more information.
> +
> +		* "-EFBIG" : System information exceeds PAGE_SIZE.

-- 
~Randy

Re: [PATCH v2 06/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document affinity_domain_via_virtual_processor sysfs interface file

[Randy Dunlap]

Hi--

On 7/10/23 02:27, Kajol Jain wrote:
> 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    | 32 +++++++++++++++++++
>  1 file changed, 32 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 aff52dc3b05c..3b63d66658fe 100644
> --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> @@ -144,3 +144,35 @@ Description:	admin read only
>  			   more information.
>  
>  		* "-EFBIG" : System information exceeds PAGE_SIZE.
> +
> +What:		/sys/devices/hv_gpci/interface/affinity_domain_via_virtual_processor
> +Date:		July 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 will be created only for power10 and above platforms.
> +
> +		* User needs root privileges to read data from this sysfs file.
> +
> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",

		                                                                H_SUCCESS

> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.

		            s/and/or/

> +
> +		  HCALL with return error type "H_AUTHORITY", can be resolved during

		Drop the comma:                             ^

> +		  runtime by setting "Enable Performance Information Collection" option.
> +
> +		* The end user reading this sysfs file must decode the content as per
> +		  underlying 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.
> +
> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
> +			   or because of some hardware error. Refer getPerfCountInfo documentation for

			                                      Refer to

> +			   more information.
> +
> +		* "-EFBIG" : System information exceeds PAGE_SIZE.

-- 
~Randy

Re: [PATCH v2 08/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document affinity_domain_via_domain sysfs interface file

[Randy Dunlap]

Hi,

On 7/10/23 02:27, Kajol Jain wrote:
> 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    | 32 +++++++++++++++++++
>  1 file changed, 32 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 3b63d66658fe..d8e65b93d1f7 100644
> --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> @@ -176,3 +176,35 @@ Description:	admin read only
>  			   more information.
>  
>  		* "-EFBIG" : System information exceeds PAGE_SIZE.
> +
> +What:		/sys/devices/hv_gpci/interface/affinity_domain_via_domain
> +Date:		July 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 will be created only for power10 and above platforms.
> +
> +		* User needs root privileges to read data from this sysfs file.
> +
> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",

		                                                                typo

> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.

		              s/and/or/

> +
> +		  HCALL with return error type "H_AUTHORITY", can be resolved during

		Drop the comma:                             ^

> +		  runtime by setting "Enable Performance Information Collection" option.
> +
> +		* The end user reading this sysfs file must decode the content as per
> +		  underlying 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.
> +
> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
> +			   or because of some hardware error. Refer getPerfCountInfo documentation for

			                                      Refer to

> +			   more information.
> +
> +		* "-EFBIG" : System information exceeds PAGE_SIZE.

-- 
~Randy

Re: [PATCH v2 10/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document affinity_domain_via_partition sysfs interface file

[Randy Dunlap]

Hi,

Same correction comments as in the other 4 patches (not repeated here).


On 7/10/23 02:27, Kajol Jain wrote:
> 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    | 32 +++++++++++++++++++
>  1 file changed, 32 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 d8e65b93d1f7..b03b2bd4b081 100644
> --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
> @@ -208,3 +208,35 @@ Description:	admin read only
>  			   more information.
>  
>  		* "-EFBIG" : System information exceeds PAGE_SIZE.
> +
> +What:		/sys/devices/hv_gpci/interface/affinity_domain_via_partition
> +Date:		July 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 will be created only for power10 and above platforms.
> +
> +		* User needs root privileges to read data from this sysfs file.
> +
> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
> +
> +		  HCALL with return error type "H_AUTHORITY", can be resolved during
> +		  runtime by setting "Enable Performance Information Collection" option.
> +
> +		* The end user reading this sysfs file must decode the content as per
> +		  underlying 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.
> +
> +		* "-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.

-- 
~Randy

Re: [PATCH v2 02/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_bus_topology sysfs interface file

[kajoljain]

Thanks Randy for the review comments, I will do these updates
for all documentation patches in my next version of patchset.

Thanks,
Kajol Jain

On 7/12/23 02:22, Randy Dunlap wrote:
> Hi--
> 
> On 7/10/23 02:27, Kajol Jain wrote:
>> 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    | 32 +++++++++++++++++++
>>  1 file changed, 32 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..2eeeab9a20fa 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 +80,35 @@ 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:		July 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 will be created only for power10 and above platforms.
>> +
>> +		* User needs root privileges to read data from this sysfs file.
>> +
>> +		* This sysfs file will be created, only when the HCALL returns "H_SUCESS",
> 
> 		                                                                H_SUCCESS
> 
>> +		  "H_AUTHORITY" and "H_PARAMETER" as the return type.
> 
> 		            s/and/or/
> 
>> +
>> +		  HCALL with return error type "H_AUTHORITY", can be resolved during
> 
> 		                             Drop the comma ^
> 
>> +		  runtime by setting "Enable Performance Information Collection" option.
>> +
>> +		* The end user reading this sysfs file must decode the content as per
>> +		  underlying 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.
>> +
>> +		* "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
>> +			   or because of some hardware error. Refer getPerfCountInfo documentation for
> 
> 			                                      Refer to
> 
>> +			   more information.
>> +
>> +		* "-EFBIG" : System information exceeds PAGE_SIZE.
>