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Message-Id: <20230710092717.55317-6-kjain@linux.ibm.com>
Date: Mon, 10 Jul 2023 14:57:12 +0530
From: Kajol Jain <kjain@...ux.ibm.com>
To: mpe@...erman.id.au
Cc: linuxppc-dev@...ts.ozlabs.org, maddy@...ux.ibm.com,
atrajeev@...ux.vnet.ibm.com, disgoel@...ux.ibm.com,
kjain@...ux.ibm.com, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 05/10] 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.
Signed-off-by: Kajol Jain <kjain@...ux.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
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