On Thu, Sep 23, 2021 at 09:35:32AM +0300, Leon Romanovsky wrote: > On Wed, Sep 22, 2021 at 04:59:30PM -0500, Bjorn Helgaas wrote: > > On Wed, Sep 22, 2021 at 01:38:50PM +0300, Leon Romanovsky wrote: > > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > > > > > The PCI core uses the VF index internally, often called the vf_id, > > > during the setup of the VF, eg pci_iov_add_virtfn(). > > > > > > This index is needed for device drivers that implement live migration > > > for their internal operations that configure/control their VFs. > > > > > > Specifically, mlx5_vfio_pci driver that is introduced in coming patches > > > from this series needs it and not the bus/device/function which is > > > exposed today. > > > > > > Add pci_iov_vf_id() which computes the vf_id by reversing the math that > > > was used to create the bus/device/function. > > > > > > Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxx> > > > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > > > Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx> > > > > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > > mlx5_core_sriov_set_msix_vec_count() looks like it does basically the > > same thing as pci_iov_vf_id() by iterating through VFs until it finds > > one with a matching devfn (although it *doesn't* check for a matching > > bus number, which seems like a bug). > > > > Maybe that should use pci_iov_vf_id()? > > Yes, I gave same comment internally and we decided to simply reduce the > amount of changes in mlx5_core to have less distractions and submit as a > followup. Most likely will add this hunk in v1. I guess it backfired as far as reducing distractions, because now it just looks like a job half-done. And it still looks like the existing code is buggy. This is called via sysfs, so if the PF is on bus X and the user writes to sriov_vf_msix_count for a VF on bus X+1, it looks like mlx5_core_sriov_set_msix_vec_count() will set the count for the wrong VF. Bjorn
