Re: Addressing architectural differences between FUSE driver and fs - Re: virtio-fs tests between host(x86) and dpu(arm64)

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Mon, Jun 03, 2024 at 11:06:19AM +0200, Miklos Szeredi wrote:
> On Mon, 3 Jun 2024 at 10:53, Peter-Jan Gootzen <pgootzen@nvidia.com> wrote:
> 
> > We also considered this idea, it would kind of be like locking FUSE into
> > being x86. However I think this is not backwards compatible. Currently
> > an ARM64 client and ARM64 server work just fine. But making such a
> > change would break if the client has the new driver version and the
> > server is not updated to know that it should interpret x86 specifically.
> 
> This would need to be negotiated, of course.
> 
> But it's certainly simpler to just indicate the client arch in the
> INIT request.   Let's go with that for now.

In the long term it would be cleanest to choose a single canonical
format instead of requiring drivers and devices to implement many
arch-specific formats. I liked the single canonical format idea you
suggested.

My only concern is whether there are more commands/fields in FUSE that
operate in an arch-specific way (e.g. ioctl)? If there really are parts
that need to be arch-specific, then it might be necessary to negotiate
an architecture after all.

Stefan

> 
> Thanks,
> Miklos
> 

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