Re: remove the nvlink2 pci_vfio subdriver v2

Greg Kroah-Hartman
2021-05-04T12:59:12Z

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