Archipelago » qemu

 - setting up coalesced memory for kvm

 - setting up ioeventfd regions for kvm

The root of the tree is memory as seen from the CPU's viewpoint (the system

bus).  Nodes in the tree represent other buses, memory controllers, and

memory regions that have been rerouted.  Leaves are RAM and MMIO regions.

  descending priority order

  - if the address lies outside the region offset/size, the subregion is

    discarded

  - if the subregion is a container, the same algorithm is used within the

    subregion (after the address is adjusted by the subregion offset)

  - if the subregion is an alias, the search is continues at the alias target

4GB of memory.

The memory controller diverts addresses in the range 640K-768K to the PCI

higher priority so it obscures the RAM at the same addresses.  The vga window

can be removed by programming the memory controller; this is modelled by

removing the alias and exposing the RAM underneath.

 - .impl.min_access_size, .impl.max_access_size define the access sizes

   (in bytes) supported by the *implementation*; other access sizes will be

   emulated using the ones available.  For example a 4-byte write will be

 - .impl.valid specifies that the *implementation* only supports unaligned

   accesses; unaligned accesses will be emulated by two aligned accesses.

 - .old_portio and .old_mmio can be used to ease porting from code using