Memory Layout of the Jailhouse Hypervisor
=========================================

While the hypervisor is running, two memory regions are visible it its address
space: the hypervisor region and the remapping region. Jailhouse cells are not
mapped into hypervisor's address space, with the exception of explicitly shared
pages and pages that are temporarily mapped, e.g. during MMIO instruction
parsing.


Hypervisor region
-----------------

The hypervisor region contains both code and data of the hypervisor. It
consists of contiguous physical RAM, mapped at a fixed virtual address, both
in the hypervisor and the Linux address space. This identical mapping is
required during startup and shutdown of the hypervisor.

Virtual address: JAILHOUSE_BASE
Size: as defined in the system configuration (see hypervisor_memory.size) [1]

        +--------------------------------------+ - lower address
        | Header [2]                           |
        +--------------------------------------+
        | Text Segment                         |
        |                                      |
        |                                      |
        +--------------------------------------+
        | Read-only Data Segment               |
        |                                      |
        +--------------------------------------+
        | Data Segment                         |
        |                                      |
        +--------------------------------------+
        | BSS Segment                          |
        |                                      |
        +--------------------------------------+
        | Page +-----------------------------+ |
        | Pool | Per-CPU Data                | |
        |      |                             | |
        |      |                             | |
        |      +-----------------------------+ |
        |      | System Config               | |
        |      |                             | |
        |      +-----------------------------+ |
        |      | Page Pool Allocation Bitmap | |
        |      +-----------------------------+ |
        |      | Dynamic Page Pool           | |
        :      :                             : :
        :      :                             : :
        |      |                             | |
        |      +-----------------------------+ |
        +--------------------------------------+ - higher address


Remapping region
----------------

The remapping region is range of reserved virtual memory in the hypervisor
address space. It is used to map MMIO, platform configuration memory (ACPI on
x86) and, temporarily, selected guest pages for hypervisor access.

Virtual address: REMAP_BASE
Size: PAGE_SIZE * NUM_REMAP_BITMAP_PAGES * PAGE_SIZE * 8

        +--------------------------------------+
        | Per-CPU Temporary Mapping Region     |
        |                                      |
        +--------------------------------------+
        | Dynamic Remapping Page pool          |
        :                                      :
        :                                      :
        |                                      |
        +--------------------------------------+


References
----------

[1] Documentation/configuration-format.txt
[2] Documentation/bootstrap-interface.txt