Re: [PATCH v7] Add udmabuf misc device

From: Gert Wollny
Date: Mon Sep 10 2018 - 05:19:51 EST

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.