Re: [PATCH v7] Add udmabuf misc device

[Gert Wollny]

Am Montag, den 10.09.2018, 10:37 +0200 schrieb Gerd Hoffmann:
... 

> > The other question is of course, why did dma_buf_export fail for me
> > ...
> 
> What exactly did you try?

I ran 

qemu-system-x86_64 -enable-kvm -smp 5 -M q35 -m 8G \
    -drive format=raw,file=ubuntu.raw,if=virtio   \
    -net nic,model=virtio  -net user,hostfwd=tcp::2224-:22  \
    -vga virtio

ubuntu.raw = Ubuntu 18.04 (bionic) + 4.17 kernel (from Ubuntu cosmic). 

The VM boots up to a certain point, the last line from the boot log is
varying, as far as I can see it is a few lines after virtio_blk detects
the disks.  

When I add '-display sdl' the Xsession freezes. I was still able to log
in remotely and kill -9 qemu, then X11 became usable again. 

In all cases I get on the host: 
  qemu-system-x86_64: info: udmabuf: init ok

and there it stays, certainly because of the kernel bug reported. 

Best, 
Gert