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author | Steve Sistare <steven.sistare@oracle.com> | 2023-01-31 08:58:06 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-10 09:29:56 +0100 |
commit | 98bd3240f16ec1fc8890f3102acd1e49edb69b5b (patch) | |
tree | a3bcc770f890296668d6cc9af8c1222ecf660be0 | |
parent | 273fa49906a02bf9fdadbb15acfd86882d915a55 (diff) | |
download | linux-stable-98bd3240f16ec1fc8890f3102acd1e49edb69b5b.tar.gz linux-stable-98bd3240f16ec1fc8890f3102acd1e49edb69b5b.tar.bz2 linux-stable-98bd3240f16ec1fc8890f3102acd1e49edb69b5b.zip |
vfio/type1: restore locked_vm
commit 90fdd158a695d70403163f9a0e4efc5b20f3fd3e upstream.
When a vfio container is preserved across exec or fork-exec, the new
task's mm has a locked_vm count of 0. After a dma vaddr is updated using
VFIO_DMA_MAP_FLAG_VADDR, locked_vm remains 0, and the pinned memory does
not count against the task's RLIMIT_MEMLOCK.
To restore the correct locked_vm count, when VFIO_DMA_MAP_FLAG_VADDR is
used and the dma's mm has changed, add the dma's locked_vm count to
the new mm->locked_vm, subject to the rlimit, and subtract it from the
old mm->locked_vm.
Fixes: c3cbab24db38 ("vfio/type1: implement interfaces to update vaddr")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1675184289-267876-5-git-send-email-steven.sistare@oracle.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/vfio/vfio_iommu_type1.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 5a0834628752..7fa68dc4e938 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -1591,6 +1591,38 @@ static bool vfio_iommu_iova_dma_valid(struct vfio_iommu *iommu, return list_empty(iova); } +static int vfio_change_dma_owner(struct vfio_dma *dma) +{ + struct task_struct *task = current->group_leader; + struct mm_struct *mm = current->mm; + long npage = dma->locked_vm; + bool lock_cap; + int ret; + + if (mm == dma->mm) + return 0; + + lock_cap = capable(CAP_IPC_LOCK); + ret = mm_lock_acct(task, mm, lock_cap, npage); + if (ret) + return ret; + + if (mmget_not_zero(dma->mm)) { + mm_lock_acct(dma->task, dma->mm, dma->lock_cap, -npage); + mmput(dma->mm); + } + + if (dma->task != task) { + put_task_struct(dma->task); + dma->task = get_task_struct(task); + } + mmdrop(dma->mm); + dma->mm = mm; + mmgrab(dma->mm); + dma->lock_cap = lock_cap; + return 0; +} + static int vfio_dma_do_map(struct vfio_iommu *iommu, struct vfio_iommu_type1_dma_map *map) { @@ -1640,6 +1672,9 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, dma->size != size) { ret = -EINVAL; } else { + ret = vfio_change_dma_owner(dma); + if (ret) + goto out_unlock; dma->vaddr = vaddr; dma->vaddr_invalid = false; iommu->vaddr_invalid_count--; |