[PATCH 06/11] perf/x86/intel/uncore: Enable UPI topology discovery for Skylake Server

From: alexander . antonov
Date: Thu Nov 17 2022 - 07:29:40 EST


From: Alexander Antonov <alexander.antonov@xxxxxxxxxxxxxxx>

UPI topology discovery relies on data from KTILP0 (offset 0x94) and
KTIPCSTS (offset 0x120) registers which reside under IIO bus(3) on
SKX/CLX.

This patch enable UPI topology discovery on Skylake Server. Topology is
exposed through attributes /sys/devices/uncore_upi_<pmu_idx>/dieX,
where dieX is file which holds "upi_<idx1>:die_<idx2>" connected to
this UPI link.

Signed-off-by: Alexander Antonov <alexander.antonov@xxxxxxxxxxxxxxx>
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
arch/x86/events/intel/uncore_snbep.c | 130 +++++++++++++++++++++++++++
1 file changed, 130 insertions(+)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index 254ba0ad650a..f682a9a0f562 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -4253,6 +4253,132 @@ static struct intel_uncore_ops skx_upi_uncore_pci_ops = {
.read_counter = snbep_uncore_pci_read_counter,
};

+static umode_t
+skx_upi_mapping_visible(struct kobject *kobj, struct attribute *attr, int die)
+{
+ struct intel_uncore_pmu *pmu = dev_to_uncore_pmu(kobj_to_dev(kobj));
+
+ return pmu->type->topology[die][pmu->pmu_idx].upi->enabled ? attr->mode : 0;
+}
+
+static ssize_t skx_upi_mapping_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct intel_uncore_pmu *pmu = dev_to_uncore_pmu(dev);
+ struct dev_ext_attribute *ea = to_dev_ext_attribute(attr);
+ long die = (long)ea->var;
+ struct uncore_upi_topology *upi = pmu->type->topology[die][pmu->pmu_idx].upi;
+
+ return sysfs_emit(buf, "upi_%d,die_%d\n", upi->pmu_idx_to, upi->die_to);
+}
+
+#define SKX_UPI_REG_DID 0x2058
+#define SKX_UPI_REGS_ADDR_DEVICE_LINK0 0x0e
+#define SKX_UPI_REGS_ADDR_FUNCTION 0x00
+
+/*
+ * UPI Link Parameter 0
+ * | Bit | Default | Description
+ * | 19:16 | 0h | base_nodeid - The NodeID of the sending socket.
+ * | 12:8 | 00h | sending_port - The processor die port number of the sending port.
+ */
+#define SKX_KTILP0_OFFSET 0x94
+
+/*
+ * UPI Pcode Status. This register is used by PCode to store the link training status.
+ * | Bit | Default | Description
+ * | 4 | 0h | ll_status_valid — Bit indicates the valid training status
+ * logged from PCode to the BIOS.
+ */
+#define SKX_KTIPCSTS_OFFSET 0x120
+
+static int upi_fill_topology(struct pci_dev *dev, struct intel_uncore_topology *tp,
+ int pmu_idx)
+{
+ int ret;
+ u32 upi_conf;
+ struct uncore_upi_topology *upi = tp->upi;
+
+ tp->pmu_idx = pmu_idx;
+ ret = pci_read_config_dword(dev, SKX_KTIPCSTS_OFFSET, &upi_conf);
+ if (ret) {
+ ret = pcibios_err_to_errno(ret);
+ goto err;
+ }
+ upi->enabled = (upi_conf >> 4) & 1;
+ if (upi->enabled) {
+ ret = pci_read_config_dword(dev, SKX_KTILP0_OFFSET,
+ &upi_conf);
+ if (ret) {
+ ret = pcibios_err_to_errno(ret);
+ goto err;
+ }
+ upi->die_to = (upi_conf >> 16) & 0xf;
+ upi->pmu_idx_to = (upi_conf >> 8) & 0x1f;
+ }
+err:
+ return ret;
+}
+
+static int skx_upi_topology_cb(struct intel_uncore_type *type, int segment,
+ int die, u64 cpu_bus_msr)
+{
+ int idx, ret;
+ struct intel_uncore_topology *upi;
+ unsigned int devfn;
+ struct pci_dev *dev = NULL;
+ u8 bus = cpu_bus_msr >> (3 * BUS_NUM_STRIDE);
+
+ for (idx = 0; idx < type->num_boxes; idx++) {
+ upi = &type->topology[die][idx];
+ devfn = PCI_DEVFN(SKX_UPI_REGS_ADDR_DEVICE_LINK0 + idx,
+ SKX_UPI_REGS_ADDR_FUNCTION);
+ dev = pci_get_domain_bus_and_slot(segment, bus, devfn);
+ if (dev) {
+ ret = upi_fill_topology(dev, upi, idx);
+ if (ret)
+ break;
+ }
+ }
+
+ pci_dev_put(dev);
+ return ret;
+}
+
+static int skx_upi_get_topology(struct intel_uncore_type *type)
+{
+ /* CPX case is not supported */
+ if (boot_cpu_data.x86_stepping == 11)
+ return -EPERM;
+
+ return skx_pmu_get_topology(type, skx_upi_topology_cb);
+}
+
+static struct attribute_group skx_upi_mapping_group = {
+ .is_visible = skx_upi_mapping_visible,
+};
+
+static const struct attribute_group *skx_upi_attr_update[] = {
+ &skx_upi_mapping_group,
+ NULL
+};
+
+static int
+pmu_upi_set_mapping(struct intel_uncore_type *type, struct attribute_group *ag)
+{
+ return pmu_set_mapping(type, ag, skx_upi_mapping_show, UPI_TOPOLOGY_TYPE);
+}
+
+static int skx_upi_set_mapping(struct intel_uncore_type *type)
+{
+ return pmu_upi_set_mapping(type, &skx_upi_mapping_group);
+}
+
+static void skx_upi_cleanup_mapping(struct intel_uncore_type *type)
+{
+ pmu_cleanup_mapping(type, &skx_upi_mapping_group);
+}
+
static struct intel_uncore_type skx_uncore_upi = {
.name = "upi",
.num_counters = 4,
@@ -4265,6 +4391,10 @@ static struct intel_uncore_type skx_uncore_upi = {
.box_ctl = SKX_UPI_PCI_PMON_BOX_CTL,
.ops = &skx_upi_uncore_pci_ops,
.format_group = &skx_upi_uncore_format_group,
+ .attr_update = skx_upi_attr_update,
+ .get_topology = skx_upi_get_topology,
+ .set_mapping = skx_upi_set_mapping,
+ .cleanup_mapping = skx_upi_cleanup_mapping,
};

static void skx_m2m_uncore_pci_init_box(struct intel_uncore_box *box)
--
2.25.1