On Mon, Aug 16, 2021 at 02:53:18PM -0500, Sierra Guiza, Alejandro (Alex) wrote:

For above’s condition equal to connected_to_cpu , we’re explicitly 
migrating from
device memory to system memory with device generic type. In this type, 
device PTEs are
present in CPU page table.

During migrate_vma_collect_pmd walk op at migrate_vma_setup call, there’s 
a condition
for present pte that require migrate->flags be set for 
MIGRATE_VMA_SELECT_SYSTEM.
Otherwise, the migration for this entry will be ignored.

I think we might need a new SELECT flag here for IOMEM.