Re: [dpdk-dev] [PATCH 2/2] uio: new driver to support PCI MSI-X

Stephen Hemminger
2015-10-02T00:04:43Z

On Thu, 1 Oct 2015 16:40:10 -0700
Alexander Duyck <alexander.duyck@gmail.com> wrote:

> Do you really need to map IORESOURCE bars? Most drivers I can think of
> don't use IO BARs anymore. Maybe we could look at just dropping the
> code and adding it back later if we have a use case that absolutely
> needs it.
Mapping is not strictly necessary, but for virtio it acts a way to communicate
the regions.

> Also how many devices actually need resources beyond BAR 0? I'm just
> curious as I know BAR 2 on many of the Intel devices is the register
> space related to MSI-X so now we have both the PCIe subsystem and user
> space with access to this region.

VMXNet3 needs 2 bars. Most use only one.