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

[Christoph Hellwig <hch@lst.de>]

On Tue, Jan 27, 2026 at 03:33:44PM +0800, Qinyun Tan wrote:
> 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.

That sounds dangerous.

> 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.

Bjorn and other PCI folks: is there any reason to not do this in
the PCI code and leave a landmine for the drivers?

> 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.

Well, I think we have to distrupt it, at least for hot unplug.  This
sounds like we need some better handling in the core code as well.

> 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
---end quoted text---