Hello Everyone While running https://github.com/yiliu1765/qemu/tree/zhenzhong/wip/iommufd_nesting_rfcv1 I have come across particular code path that seems odd: I'm hitting an assert in softmmu/memory.c:1994 after calling a notification from vtd_flt_page_walk_level. The code in memory.c:1994 makes sure that when type==IOMMU_NOTIFIER_UNMAP, the permissions are IOMMU_NONE. But the code in vtd_flt_page_walk_level sets the permissions to read|write. This is part of the "intel_iommu: piotlb invalidation should notify unmap" commit in the iommufd_nesting_rfcv1 series. Question is: Why assert on the permissions being NONE if they might be read|write? Hope this makes sense. Don't hesitate to get back to me if you see that there is something missing in my explanation. Best -- Joel Granados