[RFC PATCH for 4.18 10/23] mm: Introduce vm_map_user_ram, vm_unmap_user_ram

Create and destroy mappings aliased to a user-space mapping with the same cache coloring as the userspace mapping. Allow the kernel to load from and store to pages shared with user-space through its own mapping in kernel virtual addresses while ensuring cache conherency between kernel and

[RFC PATCH for 4.18 10/23] mm: Introduce vm_map_user_ram, vm_unmap_user_ram

Create and destroy mappings aliased to a user-space mapping with the same cache coloring as the userspace mapping. Allow the kernel to load from and store to pages shared with user-space through its own mapping in kernel virtual addresses while ensuring cache conherency between kernel and