On Fri, Oct 18, 2019 at 10:19 AM Tiwei Bie <tiwei....@intel.com> wrote:
>
> On Thu, Oct 17, 2019 at 01:56:28PM +0200, David Marchand wrote:
> > On x86, iopl permissions are only needed when the virtio devices are
> > bound to a uio kernel module.
> >
> > When running a dpdk application as non root, the virtio driver was
> > refusing to register because of this check while it could work when
> > binding the device to vfio (requires to have a vIOMMU configured).
> >
> > We still need to call rte_eal_iopl_init() in the constructor so that
> > the interrupt thread would inherit this permission in the case it could
> > be used with UIO later.
> > Log a warning message for the user to understand what is wrong.
> >
> > Signed-off-by: David Marchand <david.march...@redhat.com>
> > ---
> > drivers/net/virtio/virtio_ethdev.c | 8 ++------
> > 1 file changed, 2 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/net/virtio/virtio_ethdev.c
> > b/drivers/net/virtio/virtio_ethdev.c
> > index 7261109..3506ca0 100644
> > --- a/drivers/net/virtio/virtio_ethdev.c
> > +++ b/drivers/net/virtio/virtio_ethdev.c
> > @@ -1995,11 +1995,6 @@ exit:
> > static int eth_virtio_pci_probe(struct rte_pci_driver *pci_drv
> > __rte_unused,
> > struct rte_pci_device *pci_dev)
> > {
> > - if (rte_eal_iopl_init() != 0) {
> > - PMD_INIT_LOG(ERR, "IOPL call failed - cannot use virtio PMD");
> > - return 1;
> > - }
> > -
> > /* virtio pmd skips probe if device needs to work in vdpa mode */
> > if (vdpa_mode_selected(pci_dev->device.devargs))
> > return 1;
> > @@ -2031,7 +2026,8 @@ static struct rte_pci_driver rte_virtio_pmd = {
> >
> > RTE_INIT(rte_virtio_pmd_init)
> > {
> > - rte_eal_iopl_init();
> > + if (rte_eal_iopl_init() != 0)
> > + PMD_INIT_LOG(WARNING, "IOPL call failed - virtio devices
> > won't be functional if bound to UIO drivers");
>
> Basically this will undo what below commit did, i.e.
> annoying log will show again.
>
> https://github.com/DPDK/dpdk/commit/705dced4a72a1053368c84c4b68f04f028a78b30
Yes.. true.
I wanted to keep a trace for debug, so maybe lower this to debug
level, or just drop this message.
>
> Maybe it's better to print this error when we really
> need the port IO (legacy device):
virtio calls rte_pci_ioport_map, so I suppose we can change the log
level to ERR in the first patch of this series:
http://patchwork.dpdk.org/patch/61370/
And I suppose I could add some context in this log, like the device name.
>
> https://github.com/DPDK/dpdk/blob/31b798a6f08e9b333b94b8bb26910209aa810b73/drivers/net/virtio/virtio_pci.c#L679-L680
> https://github.com/DPDK/dpdk/blob/31b798a6f08e9b333b94b8bb26910209aa810b73/drivers/net/virtio/virtio_ethdev.c#L1834-L1835
--
David Marchand
