Re: qemu-bridge-helper failed

[Berto Furth]

Hi Asif,

Can you send back the current contents of the bridge.conf file and show the attributes of it?

cat /home/asif/qemu_test/qemu-5.2.0/qemu-5.2.0/build/../etc/qemu/bridge.conf

ls -l /home/asif/qemu_test/qemu-5.2.0/qemu-5.2.0/build/../etc/qemu/bridge.conf

Are you inclined to just use good old reliable tap interfaces instead? They're my preference.

Replace the -netdev argument with

-netdev type=tap,id=net0,script="./qemu-tap-up",downscript="./qemu-tap-down"

Then make sure you have some simple "qemu-tap-up" and "qemu-tap-down" scripts that are set as executable (chmod u+x) and located in the appropriate directories. Here are some simple examples for qemu-tap-up and qemu-tap-down which use the brctl and ifconfig commands which hopefully are working on your system. They assume that virbr0 is up before QEMU is started which I think is the case on your system.

------ qemu-tap-up -----

#! /bin/sh

# qemu-ifup script to bring a network (tap) device for qemu up 

# ifconfig / brctl version

# You must specify the preexisting bridge interface you want the tap

# connected to in the variable "bridge" set below.

bridge=virbr0

brctl=$(which brctl)

echo $0 connecting $1 to $bridge

ifconfig "$1" 0.0.0.0 up

brctl addif $bridge "$1"

exit

------ qemu-tap-down -----

#! /bin/sh

# qemu-tap-down script to execute just before the tap interface is removed.

# Normally this script is empty.

echo $0 removing tap interface $1

exit

Good luck!

Berto.

On Wed, 26 May 2021, at 22:24, asif siddiqui wrote:

Hii Berto,

Thanks for the inputs. As suggested by you i tried "qemu-system-aarch64 --help | grep helper" which showed the path as /usr/local/libexec/qemu-bridge-helper, but similar output. 

Also i compiled the qemu 5.2.0 and used the following command - 

qemu-system-aarch64 -machine vexpress-a15 -cpu cortex-a57 -m 1G -kernel ifs/aarch64/$IFSNAME -drive file=fs/aarch64/fs.qcow2,if=none,id=drv0 -device virtio-blk-device,drive=drv0 -netdev bridge,br=virbr0,id=net0,helper=/home/asif/qemu_test/qemu-5.2.0/qemu-5.2.0/build/qemu-bridge-helper -device virtio-net-device,netdev=net0,mac=$MACADDR -nographic -serial mon:stdio

giving error as - 

failed to parse default acl file `/home/asif/qemu_test/qemu-5.2.0/qemu-5.2.0/build/../etc/qemu/bridge.conf'

qemu-system-aarch64: bridge helper failed

Any inputs on this ? How can i resolve failed to parse default acl file ?

Regards 

Asif

On Wed, May 26, 2021 at 2:06 AM Berto Furth <bertofurth@sent.com> wrote:

Hi Asif,

This probably isn't it, but can you triple check that the "qemu-bridge-helper" file in the expected location? I normally see that error when a helper isn't where I expect it to be.

Run something like "qemu-system-aarch64 --help | grep helper" to see the location that your version of QEMU is expecting to see the default helper at. Your version might have been compiled so that the helper file needs to be somewhere different than you expect.

Can you try to explicitly specifying the location of the helper with something like

-netdev bridge,br=$INTF,id=net0,helper=/my/directory/qemu-bridge-helper

Good luck!

Berto.

On Wed, 26 May 2021, at 00:09, asif siddiqui wrote:

Hello All, 

I am trying to enable networking in qemu(5.2.0) for QNX as a guest. As mentioned here https://wiki.qemu.org/Features/HelperNetworking i have followed the steps -

1)  enable the setuid attribute for qemu-bridge-helper file. 

2)  echo "allow virbr0" > /etc/qemu/bridge.conf

3)  chmod 0640 /etc/qemu/bridge.conf

When checked on my linux host with brctl show i got the following  - 

bridge name       bridge id                STP  enabled          interfaces

virbr0                 8000.000000000000        yes

When i run the qemu with following command line - 

qemu-system-aarch64 -machine vexpress-a15 -cpu cortex-a57 -m 1G -kernel ifs/aarch64/$IFSNAME -drive file=fs/aarch64/fs.qcow2,if=none,id=drv0 -device virtio-blk-device,drive=drv0 -netdev bridge,br=$INTF,id=net0 -device virtio-net-device,netdev=net0,mac=$MACADDR -nographic -serial mon:stdio

Please find attached the check-net.sh for enabling the network.

I get "qemu-system-aarch64: bridge helper failed". Am i missing something?  Can you please help me out here ?

Regards 

Asif

 

Attachments:

• check-net.sh