Re: [PATCH v8 00/28] vfio-user client

[John Levon <john.levon@nutanix.com>]

On Fri, Mar 14, 2025 at 03:25:53PM +0100, Cédric Le Goater wrote:

> > This is the 8th revision of the vfio-user client implementation. The vfio-user
> > protocol allows for implementing (PCI) devices in another userspace process;
> > SPDK is one example, which includes a virtual NVMe implementation.
> 
> This series is going in the right direction. Thanks for all the
> changes. However, I will postpone my review for the reasons below.
> 
> VFIO initial commit in 2012 was a single file adding support for a
> "vfio-pci" device. Since, the subsystem has changed a lot and it grew
> to +16K line of code. Over the years, we've had numerous additions,
> VFIO platform devices, s390x VFIO AP and CCW devices, migration
> support with dirty tracking, support for different host IOMMU backend
> devices, multifd, etc. All these additions never took the opportunity
> to introduce a VFIO interface for external usage and PPC, s390x,
> migration, backends subsystems happily and randomly peek and poke into
> it. The subsystem is now a happy jumble of disparate functions, with
> weak organization and names. The vfio-common.h header file is
> good example of the result.

Right, I certainly agree!

> It's time for a global code reshuffling. I'll take care of it (and
> I've already started) and this means nothing new (fixes are OK) will
> be merged before this is done. I hope I have made enough progress
> before the start of the QEMU 10.1 cycle. There won't be any functional
> changes, but there will be new files and new function names, so it's
> probably a real earthquake for your series.

It's had a couple of earthquakes already, very happy to bear the pain for a
better end result! I will try to look out for your series and review where I can
as well.

thanks
john