Re: arm/cadence_gem driver support

[Alexei Colin]

On Wed, Sep 25, 2019 at 08:52:45AM -0400, Kent Dorfman wrote:
>  This seems to negate the ability to
> set up the guest in a fully bridged network configuration where it is
> seen as a generic station on the host network.  I need a fully bridged
> network connection.

FWIW, on Xilinx's fork of Qemu (~v2.11.1) I had Cadence Ethernet working
in tap mode (with Linux guest), where the Qemu guest is recheable via a
first class tap interface on the host; not sure if that's what you refer
to as fully bridged or not.

Create a bridge device on the host and assign it an IP:
# ip link add br0 type bridge
# ip link set up dev br0
# ip addr add 10.0.2.1/24 dev br0

Install helper with setuid:
# install -o root -g root -m 4775 qemu/qemu-bridge-helper 
/usr/local/bin/qemu-bridge-helper
Grant permission to non-root users:
# echo "allow br0" > /usr/local/bin/etc/qemu/bridge.conf
                     ^ prefix set when ./configure was run

Run qemu (as non-root user should work, given the above setup) with:
-net nic,vlan=0 -net tap,vlan=0,br=br0,helper=/usr/local/bin/qemu-bridge-helper

Within guest, assign IP address and host should become reacheable:
# ip addr add 10.0.2.10/24 dev eth0
# ping 10.0.2.1

Multiple guests all connected to the same bridge worked too.