[PATCH 3/3] PCI: hv: Fix NUMA node assignment when kernel boots with custom NUMA topology

Tim Gardner tim.gardner at canonical.com
Tue Mar 15 15:19:33 UTC 2022

From: Long Li <longli at microsoft.com>

BugLink: https://bugs.launchpad.net/bugs/1961300

When kernel boots with a NUMA topology with some NUMA nodes offline, the PCI
driver should only set an online NUMA node on the device. This can happen
during KDUMP where some NUMA nodes are not made online by the KDUMP kernel.

This patch also fixes the case where kernel is booting with "numa=off".

Fixes: 999dd956d838 ("PCI: hv: Add support for protocol 1.3 and support PCI_BUS_RELATIONS2")
Signed-off-by: Long Li <longli at microsoft.com>
Reviewed-by: Michael Kelley <mikelley at microsoft.com>
Tested-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi at microsoft.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Link: https://lore.kernel.org/r/1643247814-15184-1-git-send-email-longli@linuxonhyperv.com
Signed-off-by: Wei Liu <wei.liu at kernel.org>
(cherry picked from commit 3149efcdf2c6314420c418dfc94de53bfd076b1f)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
 drivers/pci/controller/pci-hyperv.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 9017d320e9c4c..13e3048c3ee52 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1877,8 +1877,17 @@ static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
 		if (!hv_dev)
-		if (hv_dev->desc.flags & HV_PCI_DEVICE_FLAG_NUMA_AFFINITY)
-			set_dev_node(&dev->dev, hv_dev->desc.virtual_numa_node);
+		if (hv_dev->desc.flags & HV_PCI_DEVICE_FLAG_NUMA_AFFINITY &&
+		    hv_dev->desc.virtual_numa_node < num_possible_nodes())
+			/*
+			 * The kernel may boot with some NUMA nodes offline
+			 * (e.g. in a KDUMP kernel) or with NUMA disabled via
+			 * "numa=off". In those cases, adjust the host provided
+			 * NUMA node to a valid NUMA node used by the kernel.
+			 */
+			set_dev_node(&dev->dev,
+				     numa_map_to_online_node(
+					     hv_dev->desc.virtual_numa_node));

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