vdpa_sim: hold iommu_lock across dma_unmap passthrough transition

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vdpasim_dma_map() updates the IOTLB and the passthrough (iommu_pt)
state under iommu_lock.  vdpasim_dma_unmap() clears iommu_pt and
resets the IOTLB before taking iommu_lock, then deletes the mapping
while holding the lock.

A concurrent dma_map(), dma_unmap(), or reset path that also touches
the same address space can therefore observe or modify the IOTLB and
iommu_pt state without consistent locking.

Perform the passthrough transition and range deletion under the same
iommu_lock scope, matching dma_map().

Tested-on: openEuler VM (6.16.8, /usr/src/linux-6.16.8)
Tested-by: Xiong Weimin <xiongweimin@kylinos.cn>

Signed-off-by: Xiong Weimin <xiongweimin@kylinos.cn>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260626020545.607600-3-15927021679@163.com>

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Xiong Weimin 2026-06-26 10:05:45 +08:00 • committed by Michael S. Tsirkin

parent 135f0abe31

commit 7b411448c6

1 changed files with 1 additions and 2 deletions

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drivers/vdpa/vdpa_sim/vdpa_sim.c

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