On Wed, 14 Dec 2022 13:24:52 -0800
Steve Sistare <steven.sistare@xxxxxxxxxx> wrote:
> Fix bugs in the interfaces that allow the underlying memory object of an
> iova range to be mapped in a new address space. They allow userland to
> indefinitely block vfio mediated device kernel threads, and do not
> propagate the locked_vm count to a new mm.
>
> The fixes impose restrictions that eliminate waiting conditions, so
> revert the dead code:
> commit 898b9eaeb3fe ("vfio/type1: block on invalid vaddr")
> commit 487ace134053 ("vfio/type1: implement notify callback")
> commit ec5e32940cc9 ("vfio: iommu driver notify callback")
>
> Changes in V2 (thanks Alex):
> * do not allow group attach while vaddrs are invalid
> * add patches to delete dead code
> * add WARN_ON for never-should-happen conditions
> * check for changed mm in unmap.
> * check for vfio_lock_acct failure in remap
>
> Changes in V3 (ditto!):
> * return errno at WARN_ON sites, and make it unique
> * correctly check for dma task mm change
> * change dma owner to current when vaddr is updated
> * add Fixes to commit messages
> * refactored new code in vfio_dma_do_map
>
> Changes in V4:
> * misc cosmetic changes
>
> Steve Sistare (5):
> vfio/type1: exclude mdevs from VFIO_UPDATE_VADDR
> vfio/type1: prevent locked_vm underflow
> vfio/type1: revert "block on invalid vaddr"
> vfio/type1: revert "implement notify callback"
> vfio: revert "iommu driver notify callback"
>
> drivers/vfio/container.c | 5 -
> drivers/vfio/vfio.h | 7 --
> drivers/vfio/vfio_iommu_type1.c | 199 +++++++++++++++++++---------------------
> include/uapi/linux/vfio.h | 15 +--
> 4 files changed, 103 insertions(+), 123 deletions(-)
>
Looks ok to me. Jason, Kevin, I'd appreciate your reviews regarding
whether this sufficiently addresses the outstanding issues to keep this
interface around until we have a re-implementation in iommufd. Thanks,
Alex
