Hi Jiri, Mattias and all. 2023年10月4日(水) 16:36 Mattias Nissler <mniss...@rivosinc.com>:
> hi shunsuke, all, >> what about vfio-user + qemu? > > Thank you for the suggestion. FWIW, I have had some good success using VFIO-user to bridge software > components to hardware designs. For the most part, I have been hooking up > software endpoint models to hardware design components speaking the PCIe > transaction layer protocol. The central piece you need is a way to > translate between the VFIO-user protocol and PCIe transaction layer > messages, basically converting ECAM accesses, memory accesses (DMA+MMIO), > and interrupts between the two worlds. I have some code which implements > the basics of that. It's certainly far from complete (TLP is a massive > protocol), but it works well enough for me. I believe we should be able to > open-source this if there's interest, let me know. > It is what I want to do, but I'm not familiar with the vfio and vfio-user, and I have a question. QEMU has a PCI TLP communication implementation for Multi-process QEMU[1]. It is similar to your success. The multi-process qemu also communicates TLP over UDS. Could you let me know your opinion about it? One thing to note is that there are currently some limits to bridging > VFIO-user / TLP that I haven't figured out and/or will need further work: > Advanced PCIe concepts like PASID, ATS/PRI, SR-IOV etc. may lack > equivalents on the VFIO-user side that would have to be filled in. The folk > behind libvfio-user[2] have been very approachable and open to improvements > in my experience though. > > If I understand correctly, the specific goal here is testing PCIe endpoint > designs against a Linux host. What you'd need for that is a PCI host > controller for the Linux side to talk to and then hooking up endpoints on > the transaction layer. QEMU can simulate host controllers that work with > existing Linux drivers just fine. Then you can put a vfio-user-pci stub > device (I don't think this has landed in qemu yet, but you can find the > code at [1]) on the simulated PCI bus which will expose any software > interactions with the endpoint as VFIO-user protocol messages over unix > domain socket. The piece you need to bring is a VFIO-user server that > handles these messages. Its task is basically translating between VFIO-user > and TLP and then injecting TLP into your hardware design. > Yes, If the pci host controller you said can be implemented, I can achieve my goal. To begin with, I'll investigate the vfio and libvfio-user. Thanks!. [1] https://www.qemu.org/docs/master/system/multi-process.html Best, Shunsuke > > [1] https://github.com/oracle/qemu/tree/vfio-user-p3.1 - I believe that's > the latest version, Jagannathan Raman will know best > [2] https://github.com/nutanix/libvfio-user > >
