[vbox-dev] Simple PCI device for shared memory

Knut St. Osmundsen bird at sun.com
Wed May 19 14:54:25 GMT 2010

Nev wrote:
> 4. call PDMDevHlpMMIO2Register - to allocate Host R3 address space ?

This allocates the actual physical memory as well as mapping it into the
virtual address space of the VM process.  Note that you do NOT specify
any address to this API, but you get a memory pointer back from it.  The
guest will access the physical memory directly (via shadow page tables).

> 5. call PDMDevHlpMMHyperMapMMIO2 - to allocate Guest address space ?

This maps the memory into the hypervisor's raw-mode context.  This is
only necessary if there is alternative ways of accessing the memory from
the guest (the only use case is the VGA port I/O IIRC).



Kind regards / Mit freundlichen Gruessen / Vennlig hilsen,


Sun Microsystems GmbH        Knut St. Osmundsen
Werkstrasse 24               Senior Staff Engineer, VirtualBox
71384 Weinstadt, Germany     mailto:bird at sun.com

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