Re: [dpdk-dev] [PATCH] bus/pci: optimize pci device probe

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, May 6, 2020 at 1:23 PM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>
>
>
> On 5/6/20 8:43 AM, Jerin Jacob wrote:
> > On Wed, May 6, 2020 at 12:05 PM Maxime Coquelin
> > <maxime.coquelin@redhat.com> wrote:
> >>
> >> Hi,
> >>
> >> On 5/5/20 6:16 PM, David Marchand wrote:
> >>> On Tue, May 5, 2020 at 5:50 PM Jerin Jacob <jerinjacobk@gmail.com> wrote:
> >>>>>>
> >>>>>> Removing this special case could break x86 applications running with
> >>>>>> legacy virtio.
> >>>>>>
> >>>>>>
> >>>>>> On the plus side, we have been announcing for some time in virtio:
> >>>>>> RTE_PMD_REGISTER_KMOD_DEP(net_virtio, "* igb_uio | uio_pci_generic | vfio-pci");
> >>>>>
> >>>>> What is to conclude?
> >>>>> # The In-tree virtio driver uses ""* igb_uio | uio_pci_generic |
> >>>>> vfio-pci"" driver as backend and it does not need RTE_KDRV_NONE?
> >>>>> OR
> >>>>> # The in-tree, legacy virtio(const struct virtio_pci_ops legacy_op)
> >>>>> can work without any kernel driver in the backend. So RTE_KDRV_NONE
> >>>>> need?
> >>>>
> >>>> Ping. What is the conclusion? If it is former then this patch is valid.
> >>>
> >>> I am fine with dropping the legacy part, but I wanted to hear from
> >>> Maxime at least.
> >>>
> >>>
> >>
> >> IIUC, it means that with Jerin patch, Virtio Legacy devices support will
> >> be dropped as they won't be probed anymore?
> >
> > The device drivers with RTE_KDRV_NONE as the backend will not be probed.
> > 1) Are Virtio Legacy devices are type of RTE_KDRV_NONE?
>
> Virtio Legacy devices can be probed with no kernel driver.
>
> > 2) if yes, Would you like to support for virtio legacy device?
>
> I am OK to remove legacy + RTE_KDRV_NONE case, but I think it needs an
> announcement and being done in a later release to let end-users using
> that configuration time to do the change.

OK

>
> > 3) if yes, Please fix RTE_PMD_REGISTER_KMOD_DEP(net_virtio, "* igb_uio
> > | uio_pci_generic | vfio-pci");
>
> While support gets removed, what about:
>
> RTE_PMD_REGISTER_KMOD_DEP(net_virtio, "* igb_uio | uio_pci_generic |
> vfio-pci | none"); ?

+1

>
> Maxime
>