Hi Ferruh, I missed your original reply to me. Sorry.
Ferruh Yigit <ferruh.yigit at intel.com> writes: > On Tue, Jan 19, 2016 at 01:29:32PM +0200, Panu Matilainen wrote: >> On 01/19/2016 11:59 AM, Ferruh Yigit wrote: >>> On Mon, Jan 18, 2016 at 11:20:02AM -0500, Aaron Conole wrote: >>>> Ferruh Yigit <ferruh.yigit at intel.com> writes: >>>>> This work is to make DPDK ports more visible and to enable using common >>>>> Linux tools to configure DPDK ports. >>>> >>>> This is a good goal. Only question - why use an additional kernel module >>>> to do this? Is it _JUST_ for ethtool support? >>> >>> Kernel module used to create/destroy Linux net_devices, and module has a >>> simple >>> driver for that device which only handles control messages by passing them >>> into >>> userspace. >>> >>> To represent DPDK ports as Linux net_devices we need kernel support. Why? Just create tun/tap interface, no? Then you get a queue into the network stack, as well. Subscribe to netlink, and you can get all of the changes that happen in the system - just look for those messages that relate to your tun device. At least, that's what I see right away (and I have some private patches for this, and you can take them over if you want). I think most of the stuff you are trying to solve already exists, but I am probably misunderstanding something (apologies for that). >>>> I think the other stuff >>>> can be accomplished using netlink sockets + messages, no? >>> >>> Netlink sockets just used to communicate kernel-space - user-space, this is >>> not >>> why we need a kernel module, for example this communication is implemented >>> in >>> original KNI as part of FIFO. >>> >>>> The only >>>> trepidation I would have with something like this is the support from >>>> major vendors - out of tree modules are not generally supportable. Might >>>> be good to get some of the ethtool commands as netlink messages as well, >>>> then it is supportable with no 3rd party kernel modules. >>> >>> Yes, there is a out of three module problem for some distros, but >>> unfortunately >>> we are not able to find a solution for this case without an >>> external kernel module. >>> >>> This patch is still an RFC and if we receive suggested solution without a >>> kernel >>> module, we can work on it together. >> >> If it has to be in the kernel then you need to find a design that is >> upstreamable. Out of tree kernel modules are not a solution, they're a >> problem that people are working on eliminating. >> > > Hi Stephen, and other Linux experts in the mail list, > > Can you please help finding a upstreamable solution for kernel control path? > > Mainly what we are looking for is userspace network driver support in > kernel, similar to what FUSE does but a much simple version. > > Above KCP module basically does this, by having a network driver which > passing requests to userspace network driver, but it is not generic > enough. > > I wonder if it is possible make it more generic by extending rtnetlink > support: > 1- Add a new network driver to Linux (or update existing one like tun) > to forward requests, get responses. > 2- Extend rtnelink to support to attach any userspace driver to this > device? (ip link set <device> uspace <?> ?) > > Does this make sense? > > rtnetlink already supports creating interfaces, and it provides > kernel/user space communication, > with "attach" support interface learns about it's peer in usersppace > and can communicate. > > FUSE like communication method also can be alternative to transfer > request and responses, but since rtnelink support exists, no need to > create something new think. > > Thanks, > ferruh
