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
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 | 226 ++++++++++++++++++----------------------
include/uapi/linux/vfio.h | 15 +--
4 files changed, 111 insertions(+), 142 deletions(-)
--
1.8.3.1
