Re: [dpdk-dev] virtio PMD is not working with master version

[David Marchand <david.marchand@6wind.com>]

On Fri, Feb 26, 2016 at 3:23 AM, Yuanhan Liu
<yuanhan.liu@linux.intel.com> wrote:
> Mauricio, thanks for the testing and report.
>
> On Thu, Feb 25, 2016 at 02:30:18PM +0100, David Marchand wrote:
>> >From the logs, I would say I broke uio_pci_generic since we are in
>> "uio" case, but uio portio sysfs does not exist.
>> virtio pmd fell back to ioports discovery before my change.
>
> Maybe we can do same?

I suppose, but see below.

>
> ---
> diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
> index 4346973..579731c 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_pci.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
> @@ -685,12 +685,11 @@ int
>  rte_eal_pci_ioport_map(struct rte_pci_device *dev, int bar,
>                        struct rte_pci_ioport *p)
>  {
> -       int ret;
> +       int ret = -1;
>
>         switch (dev->kdrv) {
>  #ifdef VFIO_PRESENT
>         case RTE_KDRV_VFIO:
> -               ret = -1;
>                 if (pci_vfio_is_enabled())
>                         ret = pci_vfio_ioport_map(dev, bar, p);
>                 break;
> @@ -700,14 +699,14 @@ rte_eal_pci_ioport_map(struct rte_pci_device *dev, int bar,
>                 ret = pci_uio_ioport_map(dev, bar, p);
>                 break;
>         default:
> +               break;
> +       }
> +
>  #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686)
> -               /* special case for x86 ... */
> +       /* special case for x86 ... */
> +       if (ret)
>                 ret = pci_ioport_map(dev, bar, p);
> -#else
> -               ret = -1;
>  #endif
> -               break;
> -       }

What if we are supposed to do vfio here, but for some reason init failed ?
Next thing, we will call ioport_read in vfio context, but init went
through the ioports parsing => boom ?

Another issue is that when device is bound to a kernel driver (let's
say virtio-pci here), then init will succeed and pmd will kick in the
device registers.

This special case should really be narrowed down to "uio" and "none"
driver cases.


-- 
David Marchand