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From: Zide Chen <zide.chen@intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Eranian Stephane <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	Dapeng Mi <dapeng1.mi@linux.intel.com>,
	Zide Chen <zide.chen@intel.com>,
	Xudong Hao <xudong.hao@intel.com>,
	Falcon Thomas <thomas.falcon@intel.com>,
	Steve Wahl <steve.wahl@hpe.com>
Subject: [PATCH 2/2] perf/x86/intel/uncore: Fix die ID init and look up bugs
Date: Wed, 29 Oct 2025 15:07:11 -0700	[thread overview]
Message-ID: <20251029220711.57909-2-zide.chen@intel.com> (raw)
In-Reply-To: <20251029220711.57909-1-zide.chen@intel.com>

In snbep_pci2phy_map_init(), if there are more than 8 nodes,
uncore_device_to_die(ubox_dev) may return -1 if all CPUs
associated with the UBOX device are offline.  This is not an error
and we still need to populate map->pbus_to_dieid[].

If NUMA is disabled on a NUMA-capable platform, pcibus_to_node()
returns NUMA_NO_NODE and uncore_device_to_die() returns -1.  As a
result, in spr_update_device_location(), which is used on Intel SPR,
GNR etc., the PMON units are ignored and not added to the RB tree.

Use uncore_pcibus_to_dieid() instead, which retrieves topology
information from the GIDNIDMAP register of the UBOX device.

Fixes: 9a7832ce3d92 ("perf/x86/intel/uncore: With > 8 nodes, get pci bus die id from NUMA info")
Fixes: 65248a9a9ee1 ("perf/x86/uncore: Add a quirk for UPI on SPR")
Signed-off-by: Zide Chen <zide.chen@intel.com>
---
 arch/x86/events/intel/uncore.c       |  1 +
 arch/x86/events/intel/uncore_snbep.c | 13 ++++++-------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 5c3aeea5c78d..84d6e481f18f 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -77,6 +77,7 @@ int uncore_die_to_segment(int die)
 	return bus ? pci_domain_nr(bus) : -EINVAL;
 }
 
+/* Note: This API can only be used when NUMA information is available. */
 int uncore_device_to_die(struct pci_dev *dev)
 {
 	int node = pcibus_to_node(dev->bus);
diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index ad4d11762ecf..e68467f617f9 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -1471,13 +1471,7 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool
 			}
 
 			map->pbus_to_dieid[bus] = die_id = uncore_device_to_die(ubox_dev);
-
 			raw_spin_unlock(&pci2phy_map_lock);
-
-			if (WARN_ON_ONCE(die_id == -1)) {
-				err = -EINVAL;
-				break;
-			}
 		}
 	}
 
@@ -6530,7 +6524,7 @@ static void spr_update_device_location(int type_id)
 
 	while ((dev = pci_get_device(PCI_VENDOR_ID_INTEL, device, dev)) != NULL) {
 
-		die = uncore_device_to_die(dev);
+		die = uncore_pcibus_to_dieid(dev->bus);
 		if (die < 0)
 			continue;
 
@@ -6554,6 +6548,11 @@ static void spr_update_device_location(int type_id)
 
 int spr_uncore_pci_init(void)
 {
+	int ret = snbep_pci2phy_map_init(0x3250, SKX_CPUNODEID, SKX_GIDNIDMAP, true);
+
+	if (ret)
+		return ret;
+
 	/*
 	 * The discovery table of UPI on some SPR variant is broken,
 	 * which impacts the detection of both UPI and M3UPI uncore PMON.
-- 
2.51.1


  reply	other threads:[~2025-10-29 22:13 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-29 22:07 [PATCH 1/2] perf/x86/intel/uncore: Skip discovery table for offline dies Zide Chen
2025-10-29 22:07 ` Zide Chen [this message]
2025-10-30  1:39   ` [PATCH 2/2] perf/x86/intel/uncore: Fix die ID init and look up bugs Mi, Dapeng
2025-10-30  5:17     ` Chen, Zide
2025-11-13 22:33   ` Steve Wahl
2025-10-30  1:37 ` [PATCH 1/2] perf/x86/intel/uncore: Skip discovery table for offline dies Mi, Dapeng
2025-10-30  4:38   ` Chen, Zide
2025-10-30  6:23     ` Mi, Dapeng
2025-11-13 22:32 ` Steve Wahl

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