[dpdk-dev] [PATCH] bus/pci: set intr_handle type for secondary processes
Burakov, Anatoly
anatoly.burakov at intel.com
Fri Oct 19 10:02:43 CEST 2018
On 18-Oct-18 5:41 PM, Alejandro Lucero wrote:
>
>
> On Thu, Oct 18, 2018 at 5:26 PM Burakov, Anatoly
> <anatoly.burakov at intel.com <mailto:anatoly.burakov at intel.com>> wrote:
>
> On 27-Sep-18 1:30 PM, Alejandro Lucero wrote:
> > Invoking rte_pci_read/write_config functions requires device with
> > a intr_handle type for using VFIO or UIO driver related functions.
> >
> > Secondary processes rely on primary processes for device
> initialization
> > so they do not usually require using these functions. However,
> some PMDs,
> > like NFP PMD, require using these functions even for secondary
> processes.
> >
> > Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com
> <mailto:alejandro.lucero at netronome.com>>
> > ---
>
> Hi Alejandro,
>
> I’m curious of consequences of setting intr handle to a valid value
> when
> we don’t have an interrupt thread. Something may try to use it
> (although
> I couldn’t find any such usage).
>
>
> The point is secondary processes do not deal with interrupts so I assume
> setting the type does not change anything but it allows to use PCI
> read/write functions by secondary processes.
>
> PCI config read really uses intr handle type to discover userspace
> driver type – this seems ever so slightly wrong, and looks like
> something that should be part of rte_device somewhere, independent of
> interrupt types. Do we have any other alternative to do the same thing
> (i.e. know what userspace driver is used for a particular PCI device)?
>
>
> I agree current way not being specially good.
>
> Your comment has reminded me there is another way: just using the kdrv
> field from the rte_pci_device struct. I have code using that field for
> doing a different thing in the NFP PMD depending on the driver in use,
> UIO or VFIO. So I think a better patch would be just to modify those pci
> functions for using kdrv field instead.
>
> Adding Ferruh in the thread for commenting on this potential change.
>
I definitely think the way you describe would be a better way to fix
this (i.e. use kdrv in PCI config functions rather than intr handle type).
--
Thanks,
Anatoly
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