Subject: Re: remove the nvlink2 pci_vfio subdriver v2

From: Cornelia Huck <[email-masked]>
Date: Tue, 4 May 2021 15:08:51 +0200

On Tue, 4 May 2021 15:00:39 +0200
Christoph Hellwig <[email-masked]> wrote:

> On Tue, May 04, 2021 at 02:59:07PM +0200, Greg Kroah-Hartman wrote:
> > > Hi Christoph,
> > > 
> > > FYI, these uapi changes break build of QEMU.  
> > 
> > What uapi changes?
> > 
> > What exactly breaks?
> > 
> > Why does QEMU require kernel driver stuff?  
> 
> Looks like it pull in the uapi struct definitions unconditionally
> instead of having a local copy.  We could fix that by just putting
> them back, but to me this seems like a rather broken configuration
> in qemu when it pulls in headers from the running/installed kernel
> without any feature checks before using them.
> 

It is not pulling them from the installed kernel, but from a
development version to get new definitions. Removing things in the
kernel requires workarounds in QEMU until it can remove those things as
well. It is not a dumb update...