Re: [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory

Stephen Bates
2017-04-25T21:23:30Z

>> 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

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