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| author |   Li Zhe <lizhe.67@bytedance.com> | 2022-06-27 11:51:09 +0800 |
|---|---|---|
| committer |   Alex Williamson <alex.williamson@redhat.com> | 2022-06-30 11:02:40 -0600 |
| commit | ffed0518d871482e26c5826c0875bea6775446da (patch) | |
| tree | 5c701aa645b723ceedf716665fd954b82494776e | |
| parent | vfio: de-extern-ify function prototypes (diff) | |
| download | linux-dev-ffed0518d871482e26c5826c0875bea6775446da.tar.xz linux-dev-ffed0518d871482e26c5826c0875bea6775446da.zip | |
vfio: remove useless judgement
In function vfio_dma_do_unmap(), we currently prevent process to unmap
vfio dma region whose mm_struct is different from the vfio_dma->task.
In our virtual machine scenario which is using kvm and qemu, this
judgement stops us from liveupgrading our qemu, which uses fork() &&
exec() to load the new binary but the new process cannot do the
VFIO_IOMMU_UNMAP_DMA action during vm exit because of this judgement.
This judgement is added in commit 8f0d5bb95f76 ("vfio iommu type1: Add
task structure to vfio_dma") for the security reason. But it seems that
no other task who has no family relationship with old and new process
can get the same vfio_dma struct here for the reason of resource
isolation. So this patch delete it.
Signed-off-by: Li Zhe <lizhe.67@bytedance.com>
Reviewed-by: Jason Gunthorpe <jgg@ziepe.ca>
Link: https://lore.kernel.org/r/20220627035109.73745-1-lizhe.67@bytedance.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
| -rw-r--r-- | drivers/vfio/vfio_iommu_type1.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index c13b9290e357..a8ff00dad834 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -1377,12 +1377,6 @@ again: if (!iommu->v2 && iova > dma->iova) break; - /* - * Task with same address space who mapped this iova range is - * allowed to unmap the iova range. - */ - if (dma->task->mm != current->mm) - break; if (invalidate_vaddr) { if (dma->vaddr_invalid) { |