Re: [PATCH kernel v5 03/20] powerpc/vfio/iommu/kvm: Do not pin device memory

On Thu, Dec 13, 2018 at 05:17:17PM +1100, Alexey Kardashevskiy wrote:

This new memory does not have page structs as it is not plugged to
the host so gup() will fail anyway.

This adds 2 helpers:
- mm_iommu_newdev() to preregister the "memory device" memory so
the rest of API can still be used;
- mm_iommu_is_devmem() to know if the physical address is one of thise
new regions which we must avoid unpinning of.

This adds @mm to tce_page_is_contained() and iommu_tce_xchg() to test
if the memory is device memory to avoid pfn_to_page().

This adds a check for device memory in mm_iommu_ua_mark_dirty_rm() which
does delayed pages dirtying.

Signed-off-by: Alexey Kardashevskiy <redacted>

Reviewed-by: Paul Mackerras <redacted>