Re: remove the nvlink2 pci_vfio subdriver v2

Greg Kurz
2021-05-04T17:10:37Z

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.

I guess QEMU people should take some action before this percolates
to the QEMU source tree.

Cc'ing relevant QEMU lists to bring the discussion there.

Cheers,

--
Greg

> drivers/vfio/pci/vfio_pci_nvlink2.c | 490 ------------------
> 16 files changed, 12 insertions(+), 1511 deletions(-)