[PATCH V1] nvme-pci: disable SR-IOV VFs on driver unbind

[Qinyun Tan]

The NVMe PCI driver exports the sriov_configure callback via
pci_sriov_configure_simple(), which allows userspace to enable SR-IOV
VFs through sysfs. However, when the PF driver is unbound, the driver
does not disable SR-IOV, leaving VFs orphaned in the system.

This causes the PCI core to emit a warning in pci_iov_remove():
  "driver left SR-IOV enabled after remove"

According to Documentation/PCI/pci-iov-howto.rst, PCI drivers that
support SR-IOV should call pci_disable_sriov() in their remove callback
to properly clean up VFs before the driver is unloaded.

Fix this by disabling SR-IOV in nvme_remove(). If VFs are not assigned
to a guest, disable SR-IOV. If VFs are still assigned, emit a warning
since forcibly disabling would disrupt the guest.

Signed-off-by: Qinyun Tan <qinyuntan at linux.alibaba.com>
Reviewed-by: Xunlei Pang <xlpang at linux.alibaba.com>
Reviewed-by: Guixin Liu <kanie at linux.alibaba.com>
---
 drivers/nvme/host/pci.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 58f3097888a7..4f2dc13de48b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -3666,6 +3666,15 @@ static void nvme_remove(struct pci_dev *pdev)
 	nvme_stop_ctrl(&dev->ctrl);
 	nvme_remove_namespaces(&dev->ctrl);
 	nvme_dev_disable(dev, true);
+
+	if (pci_num_vf(pdev)) {
+		if (pci_vfs_assigned(pdev))
+			dev_warn(&pdev->dev,
+				 "WARNING: Removing PF while VFs are assigned - VFs will not be deallocated!\n");
+		else
+			pci_disable_sriov(pdev);
+	}
+
 	nvme_free_host_mem(dev);
 	nvme_dev_remove_admin(dev);
 	nvme_dbbuf_dma_free(dev);
-- 
2.43.5