Subject: Re: [PATCH mlx5-next v6 1/4] PCI: Add sysfs callback to allow MSI-X table size change of SR-IOV VFs

From: Jason Gunthorpe <[email-masked]>
Date: Wed, 17 Feb 2021 15:25:22 -0400

On Wed, Feb 17, 2021 at 12:02:39PM -0600, Bjorn Helgaas wrote:

> > BTW, I asked more than once how these sysfs knobs should be handled
> > in the PCI/core.
> 
> Thanks for the pointers.  This is the first instance I can think of
> where we want to create PCI core sysfs files based on a driver
> binding, so there really isn't a precedent.

The MSI stuff does it today, doesn't it? eg:

virtblk_probe (this is a driver bind)
  init_vq
   virtio_find_vqs
    vp_modern_find_vqs
     vp_find_vqs
      vp_find_vqs_msix
       vp_request_msix_vectors
        pci_alloc_irq_vectors_affinity
         __pci_enable_msi_range
          msi_capability_init
	   populate_msi_sysfs
	    	ret = sysfs_create_groups(&pdev->dev.kobj, msi_irq_groups);

And the sysfs is removed during pci_disable_msi(), also called by the
driver

Jason