[dpdk-dev] Q: uio_generic_pci

[dpdk-dev] Q: uio_generic_pci

[Ran Shalit]

Hello,

I would please like to ask about uio_generic_pci :

1. how to set irq from userspace.
Is there anything similar to
echo "3" > /sys/bus/pci/drivers/uio_pci_generic/irq
in all documentation which talk about it, it is not mentioned (or I
don't find it):
https://github.com/rumpkernel/wiki/wiki/Howto:-Accessing-PCI-devices-from-userspace
http://www.hep.by/gnu/kernel/uio-howto/uio_pci_generic.html

2. Is there a way to use dma from userspace with this driver ?

Best Regards,
Ran

Re: [dpdk-dev] Q: uio_generic_pci

[Stephen Hemminger]

On Tue, 6 Feb 2018 12:57:15 +0200
Ran Shalit <ranshalit@gmail.com> wrote:

> Hello,
> 
> I would please like to ask about uio_generic_pci :
> 
> 1. how to set irq from userspace.

No. that is not generally possible.
It is expected that the IRQ will come from the hardware device.
On some hardware it is possible to poke a register and cause an interrupt.

> Is there anything similar to
> echo "3" > /sys/bus/pci/drivers/uio_pci_generic/irq
> in all documentation which talk about it, it is not mentioned (or I
> don't find it):
> https://github.com/rumpkernel/wiki/wiki/Howto:-Accessing-PCI-devices-from-userspace
> http://www.hep.by/gnu/kernel/uio-howto/uio_pci_generic.html
> 
> 2. Is there a way to use dma from userspace with this driver ?

This driver does not provide mappings of the PCI memory regions
so DMA is not possible. Use VFIO-pci or igb_uio instead.