[vbox-dev] Access to framebuffer from EMT thread(s)

[Anna Fischer]

Hi,

I'm currently working on a graphics frontend for VirtualBox 5. I've looked into the VirtualBox one shipping with the source code, and I'm wondering about access to the virtualized framebuffer from the EMT thread(s). I guess that this access must be locked/synchronized? Can one of the developers maybe confirm to me that it is possible to have multiple EMT threads accessing the framebuffer (at the same time)? In KVM/qemu for example there is just one I/O thread taking care of graphics I/O (as far as I remember) so in that case it didn't really need to be locked. But from reading the VirtualBox source code, it seems to me as if a frontend must synchronize updates from multiple EMT threads?

Many thanks for your help.

Anna