On Tue, 31 Jan 2023 08:58:02 -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. Also fix a pre-existing bug
> that allows locked_vm underflow.
>
> 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
>
> Changes in V5 (thanks Jason and Kevin):
> * grab mm and use it for locked_vm accounting
> * separate patches for underflow and restoring locked_vm
> * account for reserved pages
> * improve error messages
>
> Changes in V6:
> * drop "count reserved pages" patch
> * add "track locked_vm" patch
> * grab current->mm not group_leader->mm
> * simplify vfio_change_dma_owner
> * fix commit messages
>
> Changes in v7:
> * compare current->mm not group_leader->mm (missed one)
> * misc cosmetic changes
>
> Changes in v8:
> * updated group_leader comment in vfio_dma_do_map
> * delete async arg from mm_lock_acct
> * pass async=false to vfio_lock_acct in vfio_pin_page_external
> * locked_vm becomes size_t
> * improved commit message in "restore locked_vm"
> * simplified flow in vfio_change_dma_owner
> * rebase to v6.2-rc6
>
> Steve Sistare (7):
> vfio/type1: exclude mdevs from VFIO_UPDATE_VADDR
> vfio/type1: prevent underflow of locked_vm via exec()
> vfio/type1: track locked_vm per dma
> vfio/type1: restore locked_vm
> 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 | 248 ++++++++++++++++++----------------------
> include/uapi/linux/vfio.h | 15 ++-
> 4 files changed, 120 insertions(+), 155 deletions(-)
>
Applied to vfio next branch for v6.3. Thanks,
Alex
