qemu virtio_ioport_write error
 

Hi,

The host system is slackware64 14.2 and guest vm is also slackware64 14.2

I use the following script to start the VM

/usr/bin/qemu-system-x86_64
-name vm01
-machine q35,accel=kvm,kernel_irqchip=on
-cpu qemu64
-smp cores=2
-m 1G
-rtc base=utc
-monitor vc
-vga std
-usbdevice tablet
-enable-kvm
-qmp unix:/vm/control/vm01,server,nowait
-pidfile /vm/control/vm01.pid
-display vnc=127.0.0.1:1 -netdev tap,id=hn0,helper=/usr/libexec/qemu-bridge-helper --br=br0,vhost=on
-device virtio-net-pci,netdev=hn0,id=nic0,mac=11:11:00:11:00:11
-drive file=vm.qcow2,index=0,media=disk,cache=writeback,if=virtio

Everything running fine under qemu-2.6.2

but when upgraded to qemu-2.7.1 or qemu-2.8.1.1 or qemu-2.9.0, every time when the vm start, an message is appear:

virtio_ioport_write: unexpected address 0x17 value 0xf0

It seems that the message is related to the disk mount action of the vm.

Although the vm is also running well under qemu-2.7.1, qemu-2.8.1.1 and qemu-2.9.0, this error message make me feel worrying.

Any hints?
Thanks.

hi ziduck, welcome to LQ!

I just tried your script here with a slightly different configuration (no bridge) and I don't have the message you report (and the vm runs just fine)
so, if noone else more into the qemu syntax than me steps in, I think your best options should be:
- check if something has changed in the qemu syntax after version 2.6.x;
- ask on irc or in the qemu-discuss mailing list.

Hi ponce,

I tried reinstall the guest from Slackware64-14.2 DVD with qemu-2.9.0.

The result:

With -drive file=vm.qcow2,index=0,media=disk,cache=writeback,if=virtio
message appeared: qemu-system-x86_64: virtio_ioport_write: unexpected address 0x17 value 0xf0

With (without the if=virtio) -drive file=vm.qcow2,index=0,media=disk,cache=writeback
no error or warning message

I also tried install the guest from devuan_jessie_1.0.0_amd64_DVD.iso.
With or without the if=virtio, no error message in both cases.

I think it may related to the disk virtio module in slackware14.2, not the syntax of qemu.

Thanks

One more thing:

I also tried the slackware64-14.1.iso.
With or without the if=virtio, no error message in both cases.

May be related to the the kernel (4.x vs 3.x) in the vm guest.

so it's not tied to the qemu version?

again, I think you can have a better help on this matter on the dedicated qemu channel, I doubt anybody had seen (or cared about) a similar error here.

qemu-2.6.2, no problem at all.
2.7 to 2.9 will produce the error when mounting virtio disk interface on 4.4.x Kernel (come with slackware 14.2).
will post this question on qemu list, thanks