Re: [dpdk-dev] [PATCH 0/2] uio_msi: device driver

Stephen Hemminger
2015-10-01T22:00:35Z

On Thu, 1 Oct 2015 12:48:36 -0700
Alexander Duyck <alexander.duyck@gmail.com> wrote:

> On 10/01/2015 07:57 AM, Stephen Hemminger wrote:
> > On Thu, 1 Oct 2015 13:59:02 +0300
> > Avi Kivity <avi@scylladb.com> wrote:
> >
> >> On 10/01/2015 01:28 AM, Stephen Hemminger wrote:
> >>> This is a new UIO device driver to allow supporting MSI-X and MSI devices
> >>> in userspace. It has been used in environments like VMware and older versions
> >>> of QEMU/KVM where no IOMMU support is available.
> >> Why not add msi/msix support to uio_pci_generic?
> > That is possible but that would meet ABI and other resistance from the author.
> > Also, uio_pci_generic makes it harder to find resources since it doesn't fully
> > utilize UIO infrastructure.
>
> I'd say you are better off actually taking this in the other direction.
> From what I have seen it seems like this driver is meant to deal with
> mapping VFs contained inside of guests. If you are going to fork off
> and create a UIO driver for mapping VFs why not just make it specialize
> in that. You could probably simplify the code by dropping support for
> legacy interrupts and IO regions since all that is already covered by
> uio_pci_generic anyway if I am not mistaken.
>
> You could then look at naming it something like uio_vf since the uio_msi
> is a bit of a misnomer since it is MSI-X it supports, not MSI interrupts.

The support needs to cover:
- VF in guest
- VNIC in guest (vmxnet3)
it isn't just about VF's