On Tue, 4 May 2021 16:11:31 +0200 Greg Kurz <groug@xxxxxxxx> wrote: > On Tue, 4 May 2021 15:30:15 +0200 > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > On Tue, May 04, 2021 at 03:20:34PM +0200, Greg Kurz wrote: > > > On Tue, 4 May 2021 14:59:07 +0200 > > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > 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@xxxxxx> 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? > > > > > > > > > > All macros and structure definitions that are being removed > > > from include/uapi/linux/vfio.h by patch 1. > > > > > > > What exactly breaks? > > > > > > > > > > These macros and types are used by the current QEMU code base. > > > Next time the QEMU source tree updates its copy of the kernel > > > headers, the compilation of affected code will fail. > > > > So does QEMU use this api that is being removed, or does it just have > > some odd build artifacts of the uapi things? > > > > These are region subtypes definition and associated capabilities. > QEMU basically gets information on VFIO regions from the kernel > driver and for those regions with a nvlink2 subtype, it tries > to extract some more nvlink2 related info. Urgh, let's put the uapi header back in place with a deprecation notice. Userspace should never have a dependency on the existence of a given region, but clearly will have code to parse the data structure describing that region. I'll post a patch. Thanks, Alex
