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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Greg Kurz <groug@kaod.org>
Cc: Christoph Hellwig <hch@lst.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Alex Williamson <alex.williamson@redhat.com>,
	Jason Gunthorpe <jgg@nvidia.com>,
	kvm@vger.kernel.org, David Airlie <airlied@linux.ie>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Paul Mackerras <paulus@samba.org>,
	Daniel Vetter <daniel@ffwll.ch>,
	linux-api@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	qemu-devel@nongnu.org, qemu-ppc@nongnu.org
Subject: Re: remove the nvlink2 pci_vfio subdriver v2
Date: Tue, 4 May 2021 14:59:07 +0200
Message-ID: <YJFFG1tSP0dUCxcX@kroah.com> (raw)
In-Reply-To: <20210504142236.76994047@bahia.lan>

On Tue, May 04, 2021 at 02:22:36PM +0200, Greg Kurz wrote:
> On Fri, 26 Mar 2021 07:13:09 +0100
> Christoph Hellwig <hch@lst.de> wrote:
> 
> > Hi all,
> > 
> > the nvlink2 vfio subdriver is a weird beast.  It supports a hardware
> > feature without any open source component - what would normally be
> > the normal open source userspace that we require for kernel drivers,
> > although in this particular case user space could of course be a
> > kernel driver in a VM.  It also happens to be a complete mess that
> > does not properly bind to PCI IDs, is hacked into the vfio_pci driver
> > and also pulles in over 1000 lines of code always build into powerpc
> > kernels that have Power NV support enabled.  Because of all these
> > issues and the lack of breaking userspace when it is removed I think
> > the best idea is to simply kill.
> > 
> > Changes since v1:
> >  - document the removed subtypes as reserved
> >  - add the ACK from Greg
> > 
> > Diffstat:
> >  arch/powerpc/platforms/powernv/npu-dma.c     |  705 ---------------------------
> >  b/arch/powerpc/include/asm/opal.h            |    3 
> >  b/arch/powerpc/include/asm/pci-bridge.h      |    1 
> >  b/arch/powerpc/include/asm/pci.h             |    7 
> >  b/arch/powerpc/platforms/powernv/Makefile    |    2 
> >  b/arch/powerpc/platforms/powernv/opal-call.c |    2 
> >  b/arch/powerpc/platforms/powernv/pci-ioda.c  |  185 -------
> >  b/arch/powerpc/platforms/powernv/pci.c       |   11 
> >  b/arch/powerpc/platforms/powernv/pci.h       |   17 
> >  b/arch/powerpc/platforms/pseries/pci.c       |   23 
> >  b/drivers/vfio/pci/Kconfig                   |    6 
> >  b/drivers/vfio/pci/Makefile                  |    1 
> >  b/drivers/vfio/pci/vfio_pci.c                |   18 
> >  b/drivers/vfio/pci/vfio_pci_private.h        |   14 
> >  b/include/uapi/linux/vfio.h                  |   38 -
> 
> 
> Hi Christoph,
> 
> FYI, these uapi changes break build of QEMU.

What uapi changes?

What exactly breaks?

Why does QEMU require kernel driver stuff?

thanks,

greg k-h

  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26  6:13 Christoph Hellwig
2021-03-26  6:13 ` [PATCH 1/2] vfio/pci: remove vfio_pci_nvlink2 Christoph Hellwig
2021-04-06 19:38   ` Alex Williamson
2021-04-12  9:41     ` Michael Ellerman
2021-04-12 14:23       ` Alex Williamson
2021-04-22 13:49         ` Michael Ellerman
2021-04-22 13:52           ` Jason Gunthorpe
2021-03-26  6:13 ` [PATCH 2/2] powerpc/powernv: remove the nvlink support Christoph Hellwig
2021-05-04 12:22 ` remove the nvlink2 pci_vfio subdriver v2 Greg Kurz
2021-05-04 12:59   ` Greg Kroah-Hartman [this message]
2021-05-04 13:00     ` Christoph Hellwig
2021-05-04 13:08       ` Cornelia Huck
2021-05-04 13:20     ` Greg Kurz
2021-05-04 13:30       ` Greg Kroah-Hartman
2021-05-04 14:11         ` Greg Kurz
2021-05-04 15:33           ` Alex Williamson
2021-05-04 14:23       ` Daniel Vetter
2021-05-04 15:53         ` Jason Gunthorpe
2021-05-04 16:30           ` Daniel Vetter

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