Commit 71a7ccb4 authored by Kajol Jain's avatar Kajol Jain Committed by Michael Ellerman
Browse files

powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity domain... 


powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity domain via virtual processor information

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.

Reviewed-by: default avatarAthira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: default avatarKajol Jain <kjain@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230729073455.7918-6-kjain@linux.ibm.com
parent 3255171d

arch/powerpc/perf/hv-gpci.c

+84 −2
Original line number Diff line number Diff line
@@ -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,

};
@@ -592,6 +670,10 @@ 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);