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Date:   Thu, 11 Mar 2021 11:43:24 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Max Gurtovoy <mgurtovoy@nvidia.com>, alex.williamson@redhat.com,
        cohuck@redhat.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, liranl@nvidia.com, oren@nvidia.com,
        tzahio@nvidia.com, leonro@nvidia.com, yarong@nvidia.com,
        aviadye@nvidia.com, shahafs@nvidia.com, artemp@nvidia.com,
        kwankhede@nvidia.com, ACurrid@nvidia.com, cjia@nvidia.com,
        yishaih@nvidia.com, mjrosato@linux.ibm.com, aik@ozlabs.ru
Subject: Re: [PATCH 9/9] vfio/pci: export igd support into vendor vfio_pci
 driver
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 <20210310081508.GB4364@lst.de>
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On Thu, Mar 11, 2021 at 12:37:06PM +0100, Christoph Hellwig wrote:
> On Wed, Mar 10, 2021 at 08:31:27AM -0400, Jason Gunthorpe wrote:
> > Yes, that needs more refactoring. I'm viewing this series as a
> > "statement of intent" and once we commit to doing this we can go
> > through the bigger effort to split up vfio_pci_core and tidy its API.
> > 
> > Obviously this is a big project, given the past comments I don't want
> > to send more effort here until we see a community consensus emerge
> > that this is what we want to do. If we build a sub-driver instead the
> > work is all in the trash bin.
> 
> So my viewpoint here is that this work doesn't seem very useful for
> the existing subdrivers given how much compat pain there is.  It
> defintively is the right way to go for a new driver.

Right, I don't think the three little drivers get much benifit, what
they are doing is giving some guidance on how to structure the vfio
pci core module. The reflck duplication you pointed at, for instance,
will be in the future drivers too.

What do you see as the most compat pain? 

Max made them full proper drivers, but we could do a half way and just
split the code like Max has done but remove the pci_driver and related
compat. It would static link in as today but still be essentially
structured like a "new driver"

Jason