Qemu: hub 0 is not connected to host network

Hi all,
I have created a virtual machine for QNX aarch64 using Qemu with the command below,

qemu-system-aarch64 -M xlnx-zcu102 -m 8G -serial mon:stdio -device loader,file=/root/xlinxbsp/images/QNX-IFS,addr=0x00100000,cpu-num=0 -nographic -global xlnx,zynqmp-boot.cpu-num=0 -global xlnx,zynqmp-boot.use-pmufw=true`

the image is received by one of the vender, and this image is working fine in the xlnx-zcu102 board.
I have installed the Qemu using Petalinux but now I am getting following error

qemu-system-aarch64: warning: hub 0 is not connected to host network

although this is a warning but it did not allowing Qemu to boot further.
I found that this message normally araise when there is not enough supporting parameter provided but how can I know what are the supporting parameters for the image I have?

any help or further information is highly appreciated :slight_smile:

Sorry, I’ve been away for a while and just catching up now.

I am sure you’ve already googled around for this, but this error is related to networking

Your command line doesn’t specify any networking parameters at all which means even if QNX booted, you would not have any networking. You need to add arguments to emulate a NIC card, specifically the one that’s used by the hardware in the real system because the QNX network driver is trying to connect to a non-existent network card and likely hanging up when it can’t find it.


Hi Tim,

No problem.

So, the issue is still there,
I still provided network configurations it does not work, like below.

-net nic,model=cadence_gem -net nic,model=cadence_gem -net nic,model=cadence_gem /
-net nic,model=cadence_gem,netdev=xzynq0 -netdev user,id=xzynq0,tftp=/tftpboot  /

This is actually just a warning. I am not sure wether this warning is stopping Qemu or is there any other booting problem.
I tried to use GDB, but my image does not have debug symbols, so its quite hard to debug.

What NIC card is cadence_gem? I doubt that is anything QNX is able to work with. I was expecting to see something like NE2000 or one of the many Intel NIC cards etc.

I think you mentioned before what the motherboard is on the actual system. Can you refresh my memory on that? Or look up the specs for that motherboard and let me know what NIC card it has on it.

The warning from QEMU is unlikely to be causing the issue. What’s more likely happening is that the QNX driver for the ethernet card is hanging up the boot process because it can’t find the NIC card.


Hi Tim,
Sorry for late rep,

I think the Network information I provided is correct as it is working with other images( the image which has issues of missing mkdir binaries)

Yes, I am using xlnx-zcu102 board on real hardware and also using the same as a machine type in Qemu.

Now, the issue is sorted out,
As I created the image myself from QNX command mkqnximage and the QNX commond generates some files (including VM image and virstual disk image) and folders. I was using the wrong image file to generate Qemu VM.
Now the Qemu VM has been created and it has mounted disk, mkdir and other essentials binarries.

There is some other binarries(libtiff.so.5) are missing which is I guess related with my application that I am looking for now.

Thank you very much for your big support, you made it possible for me to digg it into more.