>> Yes, that's why I used 'significant'. One good thing is that given resources >> it can easily be done in parallel with other development, and will give additional >> insight of some form. > >Yup, well if someone wants to start working on an emulated RDMA device >that actually simulates proper DMA transfers that would be great! Give that each RDMA vendor’s devices expose a different MMIO I don’t expect this to happen anytime soon. > Yes, the nvme device in qemu has a CMB buffer which is a good choice to > test with but we don't have code to use it for p2p transfers in the >kernel so it is a bit awkward. Note the CMB code is not in upstream QEMU, it’s in Keith’s fork [1]. I will see if I can push this upstream. Stephen [1] git://git.infradead.org/users/kbusch/qemu-nvme.git