Hi, I know a bit about VFIO implementation, have been debugging IOMMU (intel) problems, know how QEMU/KVM work about using legacy or vfio attached devices, and I'm the maintainer of a DPDK PMD recently accepted upstream which requires our particular UIO driver (not maintained upstream). So I guess I could help with this effort and testing the code with our card. Of course, I can not be full time on this but I will be happy to contribute.
On Fri, Dec 11, 2015 at 11:20 PM, Jan Viktorin <viktorin at rehivetech.com> wrote: > Hello, > > I am not involved in the vfio very much, however, I was watching some > vfio-related code in last few weeks. It looks promising to me and > IMHO it seems to the best way to bring a support of integrated Ethernet > MACs into DPDK (related to many SoCs). Unfortunately, the ARMv7 SoCs (I > know) lacks of an IOMMU... The only protection there is the TrustZone > technology but I have no idea of its support in the kernel. It's also > far from being a replacement of an IOMMU. When using FPGAs, it is > possible to put an IOMMU engine there (I've got such a prototype > somewhere in my VHDL library) but nobody will probably do use because > of saving on-chip resources. > > The X-Gene SoC (ARM 64) contains 2x 10 Gbps EMACs on the chip. I have no > idea about IOMMUs there. Thus, this platform can probably benefit of > such driver as well. The question is whether there is some interest to > have this kind of support in DPDK. > > Thus, I'd like to have the vfio/no-iommu to support the ARMv7 (otherwise > it would be effectively dead in DPDK). Unfortunately, it's not my > primary job at the moment. > > Regards > Jan > > Note: as far as I know, it is discouraged to refer to lkml.org as > it is often very slow - my case today :). > > On Fri, 11 Dec 2015 17:28:43 +0100 > Thomas Monjalon <thomas.monjalon at 6wind.com> wrote: > > > Recently there were some discussions to have an upstream replacement > > for our igb_uio module. > > Several solutions were discussed (new uio driver, uio_pci_generic, vfio): > > https://lkml.org/lkml/2015/10/16/700 > > > > Alex Williamson (maintainer of VFIO driver), submitted a solution > > and was waiting some feedback. Unfortunately, nobody caught it and > > he has reverted his work: > > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ae5515d > > > > It is an important challenge to remove our out-of-tree modules and > > especially igb_uio. It is a long way to have a standard solution > integrated > > in every distributions. > > The current cooking Linux kernel is 4.4 and will have a long term > maintenance: > > https://kernel.org/releases.html > > So it is a pity to miss this opportunity. > > > > Stephen has fixed a bug to use the IOMMU group zero: > > http://dpdk.org/browse/dpdk/commit/?id=22215f141b1 > > > > Is there someone interested to work on VFIO no-iommu and provide > > some feedbacks? > > We also need to prepare a documentation patch to explain its usage > > compared to the standard VFIO mode. > > > > Thanks > >
