On Tue, Apr 28, 2020 at 2:21 PM David Marchand <david.march...@redhat.com> wrote: > > On Sun, Apr 26, 2020 at 10:06 PM Thomas Monjalon <tho...@monjalon.net> wrote: > > > > 26/04/2020 20:41, Jerin Jacob: > > > On Sun, Apr 26, 2020 at 11:38 PM Thomas Monjalon <tho...@monjalon.net> > > > wrote: > > > > > > > > 26/04/2020 19:38, jer...@marvell.com: > > > > > From: Jerin Jacob <jer...@marvell.com> > > > > > > > > > > If the PCI device is not attached to any driver then there is no > > > > > point in probing it. As an optimization, skip the PCI device probe if > > > > > the PCI device driver of type RTE_KDRV_NONE. > > > > > > > > > > Signed-off-by: Jerin Jacob <jer...@marvell.com> > > > > > --- > > > > > Notes: > > > > > ------ > > > > > - virtio drivers does special treatment based on RTE_KDRV_UNKNOWN, > > > > > That is > > > > > the reason allowing RTE_KDRV_UNKNOWN in this patch. > > > > > - virio devices uses RTE_KDRV_UNKNOWN for some special meaning, IMO, > > > > > if it would > > > > > be better, if > > > > > a) Introduce the KDRV for virio > > > > > b) If the PCIe device of driver type NONE or UNKNOWN then not even > > > > > add in pci > > > > > list > > > > > in the scan, It will improve the boot time by avoiding operation on > > > > > unwanted device like sorting the PCI devices, scanning it, probe it, > > > > > managing > > > > > it etc. > > > > > > > > mlx4/mlx4 uses RTE_KDRV_UNKNOWN. > > > > > > OK. > > > > > > > > - Initial problem reported at http://patches.dpdk.org/patch/64999/ as > > > > > boot time printf clutter on octeontx2 devices with a lot PCI devices > > > > > which are > > > > > of type RTE_KDRV_NONE. > > > > > > > > Add a logtype for PCI driver and adjust log level accordingly > > > > to your preferences. > > > > > > > > > @@ -271,6 +271,8 @@ pci_probe_all_drivers(struct rte_pci_device *dev) > > > > > FOREACH_DRIVER_ON_PCIBUS(dr) { > > > > > + if (dev->kdrv == RTE_KDRV_NONE) > > > > > + continue; > > > > > rc = rte_pci_probe_one_driver(dr, dev); > > > > > > > > Nack > > > > > > I understand mlx4/mlx5 is using RTE_KDRV_UNKNOWN, Here we are skipping > > > the RTE_KDRV_NONE, > > > What is the use case for probing the devices with RTE_KDRV_NONE? > > > > Maybe you are right. I don't remember the use case. > > I think I remember these virtio and vmxnet3 PMD were not using UIO: > > http://git.dpdk.org/old/virtio-net-pmd/tree/virtio_user.c > > http://git.dpdk.org/old/vmxnet3-usermap/tree/pmd/vmxnet3.c > > > > We need to know which case is using following code: > > > > case RTE_KDRV_NONE: > > #if defined(RTE_ARCH_X86) > > ret = pci_ioport_map(dev, bar, p); > > #endif > > break; > > > > David, please could you refresh our memory? > > The in-tree virtio-net driver directly calls rte_pci_map_device / > rte_pci_ioport_map depending on virtio legacy/modern modes. > This is why the virtio pci driver does not ask for > RTE_PCI_DRV_NEED_MAPPING to the pci bus. > > > In ioport mode, there were two options for historical reasons because > of the virtio driver you mention. > This driver did not rely on uio, and this behavior was later merged to > the current in-tree driver. > It ended up (not clean) in the pci bus driver because virtio was the > only user of this code. > > > 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? > > > -- > David Marchand >
