Re: Guest Display issue on Xen

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

+Vipul


Hi Dega,

Vipul recently found a similar issue. He is using "vfb" in the xl config
file, the guest is created but he is getting a black screen.

We checked the xenstore output and frontend and backend seem to be
properly initialized and connected. I am not sure how to proceed if not
by adding printf and printk in the relevant frontend and backend code in
Linux and QEMU to figure out where things go wrong:

drivers/video/fbdev/xen-fbfront.c in Linux
hw/display/xenfb.c in QEMU

I also suggested a workaround to Vipul [1]: do not use "vfb" at all and
instead setup a normal network connection with the domU using "vif".
Then run a vncserver in the domU and connect to it over the network
using vnclient in dom0.

Cheers,

Stefano

[1] https://marc.info/?l=xen-devel&m=166916188230575


On Wed, 30 Nov 2022, dega kiran wrote:
> Hi,
> 
> I am porting Xen Hypervisor on raspberry pi4. I could port xen minimal image 
> as host & wayland based GUI image as guest. Now I am trying to
> bring up guest Display (using vncviewer) which is not coming up, even I could 
> see xen-fbfront driver on guest and Debugged
> 
> xen-fbfront.c
> 
> Xenbusprobe_backend.c
> 
> Xenbusprobe_frontend.c
> 
> But not sure where is the actual issue.
> 
> Let me know which part of code will help us more  for better understanding 
> the issue.
> 
> 
>