[PATCH 5.10 017/121] PCI: hv: Fix NUMA node assignment when kernel boots with custom NUMA topology

Greg Kroah-Hartman
2022-02-21T09:16:29Z

From: Long Li <longli@microsoft.com>

commit 3149efcdf2c6314420c418dfc94de53bfd076b1f upstream.

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@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@microsoft.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Link: https://lore.kernel.org/r/1643247814-15184-1-git-send-email-longli@linuxonhyperv.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pci/controller/pci-hyperv.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1841,8 +1841,17 @@ static void hv_pci_assign_numa_node(stru
if (!hv_dev)
continue;

- 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));

put_pcichild(hv_dev);
}