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| -rw-r--r-- | docs/devel/memory.txt | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/docs/devel/memory.txt b/docs/devel/memory.txt index 811b1bd3c5..8ed810f8b9 100644 --- a/docs/devel/memory.txt +++ b/docs/devel/memory.txt @@ -91,6 +91,37 @@ one of whose subregions is a low priority "background" region covering the whole address range; this is often clearer and is preferred. Subregions cannot be added to an alias region. +Migration +--------- + +Where the memory region is backed by host memory (RAM, ROM and +ROM device memory region types), this host memory needs to be +copied to the destination on migration. These APIs which allocate +the host memory for you will also register the memory so it is +migrated: + - memory_region_init_ram() + - memory_region_init_rom() + - memory_region_init_rom_device() + +For most devices and boards this is the correct thing. If you +have a special case where you need to manage the migration of +the backing memory yourself, you can call the functions: + - memory_region_init_ram_nomigrate() + - memory_region_init_rom_nomigrate() + - memory_region_init_rom_device_nomigrate() +which only initialize the MemoryRegion and leave handling +migration to the caller. + +The functions: + - memory_region_init_resizeable_ram() + - memory_region_init_ram_from_file() + - memory_region_init_ram_from_fd() + - memory_region_init_ram_ptr() + - memory_region_init_ram_device_ptr() +are for special cases only, and so they do not automatically +register the backing memory for migration; the caller must +manage migration if necessary. + Region names ------------ |