[V2,0/5] fixes for virtual address update

Message

Steven Sistare Dec. 13, 2022, 7:40 p.m. UTC

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 from V1 (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

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 | 163 +++++++++++++---------------------------
 include/uapi/linux/vfio.h       |  15 ++--
 4 files changed, 63 insertions(+), 127 deletions(-)