[vbox-dev] host calling into vm for async I/O?

[Huihong Luo]

Sander,
 
Thanks, I understand it. For each vm system thread that waits for directory change 
events, we can launch a host thread. 
 
Another way is not to use the vbox mechanism, instead, using tcp/ip communication between host and vm, but this won't work if networking is disabled. This is how the current windows sharing (samba) are implemented.
 
Huihong

--- On Tue, 7/15/08, Sander van Leeuwen <Sander.Vanleeuwen at Sun.COM> wrote:

From: Sander van Leeuwen <Sander.Vanleeuwen at Sun.COM>
Subject: Re: [vbox-dev] host calling into vm for async I/O?
To: "VirtualBox developer's list" <vbox-dev at virtualbox.org>
Cc: huisinro at yahoo.com
Date: Tuesday, July 15, 2008, 1:15 AM


Let me clarify this a bit more on the blocking case. Inside the guest you need to create a (kernel) thread that calls the host HGCM service and waits for an answer, which it will get when the host service detects a directory change. As the host service is single threaded, you need to create a separate thread that monitors for directory changes. That additional host thread will asynchronously complete the HGCM service call the guest makes. 
This means the HGCM service call made by the guest is not completed inside the svcCall handler (by calling g_pHelpers->pfnCallComplete).

Sander

Sander van Leeuwen wrote: 
There's is no such reversed callback mechanism for HGCM. You'd either have to poll or make a guest thread block in a wait for directory change HGCM call. The latter
is not that easy as an HGCM client is single threaded.

Sander


Huihong Luo wrote: 





Are there any APIs that can invoke vm's functions from host (opposite to VbglHGCMCall which does vm to host calls)?

I am trying to implement directory change notification features on windows shared folders. Basically, when files change in a host folder, I want the host to invoke a callback function inside vm.
 
Thanks,
 
Huihong

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Sun Microsystems GmbH        Sander van Leeuwen
Werkstrasse 24               Senior Staff Engineer, VirtualBox
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-- 
Kind regards / Mit freundlichen Gruessen / Met vriendelijke groet

--

Sun Microsystems GmbH        Sander van Leeuwen
Werkstrasse 24               Senior Staff Engineer, VirtualBox
71384 Weinstadt, Germany     mailto:Sander.Vanleeuwen at sun.com


================================================
Sitz der Gesellschaft: Sun Microsystems GmbH,
Sonnenallee 1, 85551 Kirchheim-Heimstetten
Amtsgericht Muenchen: HRB 161028
Geschaeftsfuehrer: Thomas Schroeder,
Wolfgang Engels, Dr. Roland Boehmer
Vorsitzender des Aufsichtsrates: Martin Haering
================================================
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