[Bug 1856834] [NEW] softmmu qemu-system-ppc freezes at virtio vda

[ecsdn]

Public bug reported:

The same qemu -M mpc... command that works on qemu-system-ppc version
2.8.0 freezes guest on bootup and shows error for qemu-system-ppc
version 4.2.0release and 4.19dirtygit:

qemu-system-ppc: virtio-blk failed to set guest notifier (-24), ensure -accel 
kvm is set.
qemu-system-ppc: virtio_bus_start_ioeventfd: failed. Fallback to userspace 
(slower).

ends/freezes at:
nbd: registered device at major 43
 vda:

I'm using -drive file=/home/me/rawimage.dd,if=virtio and works fine in
version 2.8.0 installed with apt-get install (Ubuntu 17.04) and also
with 2.8.0 official release from git/github that I compiled/built
myself. But both of the newer releases fail on the same exact machine
same config.

I also noticed that qemu-2.8.0 was fine with mtd but the newer ones I tried 
weren't, ie gave
qemu-system-ppc: -drive if=mtd: machine type does not support 
if=mtd,bus=0,unit=0
(but I removed -drive if=mtd since wasn't using it anyway)

I also tried on windows but I think virtio doesn't work on windows hosts
at all? On windows host it fails the same way, even version 2.12 as well
as 4.1.10...

used:
./configure --prefix=/opt/... --enable-fdt --enable-kvm --enable-debug

(basically all steps the same on same exact system same config, yet
2.8.0 works fine whether apt-get installed or built from source while
the others I built, 4.19/4.2.0 or 2.12/4.1.10(win) don't.)

In case newer qemu versions act weird on various kernels, I did try with both 
vmlinuz-4.10.0-19-generic and vmlinuz-4.13.12-041312-generic (I didn't compile 
them but I can provide config-..files. This is on Ubuntu 17.04 x86_64 host 
emulating e500v2 cpm guest, ie -M mpc... GUEST kernel 2.6.32.44 which is why I 
can't use -M ppce500 instead..)
tx
     ecs

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1856834

Title:
  softmmu qemu-system-ppc freezes at virtio vda

Status in QEMU:
  New

Bug description:
  The same qemu -M mpc... command that works on qemu-system-ppc version
  2.8.0 freezes guest on bootup and shows error for qemu-system-ppc
  version 4.2.0release and 4.19dirtygit:

  qemu-system-ppc: virtio-blk failed to set guest notifier (-24), ensure -accel 
kvm is set.
  qemu-system-ppc: virtio_bus_start_ioeventfd: failed. Fallback to userspace 
(slower).

  ends/freezes at:
  nbd: registered device at major 43
   vda:

  I'm using -drive file=/home/me/rawimage.dd,if=virtio and works fine in
  version 2.8.0 installed with apt-get install (Ubuntu 17.04) and also
  with 2.8.0 official release from git/github that I compiled/built
  myself. But both of the newer releases fail on the same exact machine
  same config.

  I also noticed that qemu-2.8.0 was fine with mtd but the newer ones I tried 
weren't, ie gave
  qemu-system-ppc: -drive if=mtd: machine type does not support 
if=mtd,bus=0,unit=0
  (but I removed -drive if=mtd since wasn't using it anyway)

  I also tried on windows but I think virtio doesn't work on windows
  hosts at all? On windows host it fails the same way, even version 2.12
  as well as 4.1.10...

  used:
  ./configure --prefix=/opt/... --enable-fdt --enable-kvm --enable-debug

  (basically all steps the same on same exact system same config, yet
  2.8.0 works fine whether apt-get installed or built from source while
  the others I built, 4.19/4.2.0 or 2.12/4.1.10(win) don't.)

  In case newer qemu versions act weird on various kernels, I did try with both 
vmlinuz-4.10.0-19-generic and vmlinuz-4.13.12-041312-generic (I didn't compile 
them but I can provide config-..files. This is on Ubuntu 17.04 x86_64 host 
emulating e500v2 cpm guest, ie -M mpc... GUEST kernel 2.6.32.44 which is why I 
can't use -M ppce500 instead..)
  tx
       ecs

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