I have a question regarding VGA passthrough. If I understood correctly, the only way to have VGA passthrough is hiding the VGA from the Dom0 and giving full control of it to one guest. This means, the guest should just take ownership of the device and start using it (and therefore take control of the screen, too), right? I read that one can dynamically hide PCI devices from the Dom0. What would happen if one did that with a VGA device? For example, if I am using linux with an active X server, what is likely to happen? In short, would it be possible to "switch" the control of the video card from the Dom0 to the DomU, keeping the Dom0 "alive" (IE: no crashes), then giving the VGA control back to the Dom0 after stopping the guest? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
David TECHER
2011-Oct-12 21:24 UTC
Re : [Xen-users] General questions about VGA passthrough
I will answer from my experiment using my nvidia graphic card. The answer may be different for ATI or Intel> I have a question regarding VGA passthrough. > IfI understood correctly, the only way to have VGA passthrough is hiding the VGA from the Dom0 and giving full control of it to one guest. Yes> Thismeans, the guest should just take ownership of the device and start using it (and therefore take control of the screen, too), right? Yes> I read that one can dynamically hide PCI devices from the Dom0.Possible before starting the domU...I never tried to do that while the domU is running.> Whatwould happen if one did that with a VGA device?> For example, if I amusing linux with an active X server, what is likely to happen?> In short,would it be possible to "switch" the control of the video card from the Dom0 to the DomU, keeping the Dom0 "alive"> (IE: no crashes), thengiving the VGA control back to the Dom0 after stopping the guest? Giving control back to dom0 is not possible...Once you stop the domU (safe shutdown), you need to restart the dom0 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Francesco Cat
2011-Oct-15 11:03 UTC
Re: Re : [Xen-users] General questions about VGA passthrough
2011/10/12 Francesco Cat <heartcollector87@gmail.com>> > What would happen if one did that with a VGA device? >> > For example, if I am using linux with an active X server, what is likely >> to happen? >> > In short, would it be possible to "switch" the control of the video card >> from the Dom0 to the DomU, keeping the Dom0 "alive" >> > (IE: no crashes), then giving the VGA control back to the Dom0 after >> stopping the guest? >> >> Giving control back to dom0 is not possible...Once you stop the domU >> (safe shutdown), you need to restart the dom0 >> >Another question, this time it should be rather easy. If I have 2 VGAs, and I manage to pass one to the DomU (Secondary adapter passthrough should be doable for Xen >= 4.0 right? but that''s not important) can I still use a VNC connection to the DomU? I hope the answer is yes, but I prefere asking since something strange might get in the way and cause problems perhaps. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Francesco Cat
2011-Oct-15 23:10 UTC
[Xen-users] Re: General questions about VGA passthrough
Thanks you a lot, this tells me it''s probably better for me to stop trying to do strange stuff with xen and just resort to a headless server for my other needs :P I''m not an expert and even if I might end up setting exactly what I need, it might take me ages to achieve. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users