[vbox-dev] Shared memory driver (PV-like)

Knut St. Osmundsen knut.osmundsen at oracle.com
Sun Feb 23 01:10:57 UTC 2014

Hi Karoline,

It would be easier to help you if you could explain more accurately what 
you want to do.

If the question is whether a host OS process can open a shared memory 
window into a guest OS process (or the other way around), then no, we 
don't provide APIs for that *yet*.  We have been giving this some 
thought already, but haven't had the need for it yet, thus not implemented.

However, if the question is whether you can write a virtual device (like 
all the src/VBox/Devices/*/Dev*.cpp files does) that talks with a guest 
OS driver using shared memory, then certainly we've been doing that 
since forever, just look at the VGA frame buffer 
(src/VBox/Devices/Graphics/DevVGA.cpp) and the VMM devices 
(src/VBox/Devices/VMMDev/VMMDev.cpp).  The VGA frame buffer is specially 
host memory (called MMIO2) that the guest accesses, while the VMMDev is 
handed contiguous guest memory like any other DMA capable device.  The 
HGSMI interface that Ramshankar mentions is a variation on what the VGA 
device does.

Kind Regards,

On 2/11/2014 2:45 PM, ramshankar venkataraman wrote:
> I'm not certain what exactly you require, but perhaps what you want is 
> something along the lines of HGCM and HGSMI (Host-Guest Shared Memory 
> Interface)? If so, take a look at src/VBox/GuestHost/HGSMI/
> Regards,
> Ram.
> On 30/01/2014 17:59, Karoline Haus wrote:
>> Hi I was wondering if there was a shared memory driver that I can use 
>> to talk between guest and host OS? Basically I'm looking for 
>> something like a para-virtualized driver that other virtualization 
>> solutions use. I haven't found anything like that in the VBox 
>> documentation. Does such a driver exists? Basically I want to be able 
>> to communicate between guest and host but not use any standard 
>> mechanisms like networking. Thanks for any pointers!
>> Karoline
>> _______________________________________________
>> vbox-dev mailing list
>> vbox-dev at virtualbox.org
>> https://www.virtualbox.org/mailman/listinfo/vbox-dev
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