Re: Virtual Network API for QEMU
On 3/31/21 10:39 PM, Radek Simko wrote:
Thank you Laine and thanks Michal for the detailed explanation.
To add some (missing) context from my side:
I was attempting to virtualize Raspberry Pi on qemu via libvirt, where
my host machine is macOS (both qemu and libvirt installed via Homebrew)
and I while trying to set up the network I stumbled upon this:
|$ virsh -c
qemu:///system?socket=/usr/local/var/run/libvirt/libvirt-sock net-list
--all error: Failed to get the number of active networks error: this
function is not supported by the connection driver: virConnectNumOfNetworks|
This error in combination with the compatibility matrix made me think
it's just not supported.
What is the right way of interpreting this error/state? Does the host OS
play a role in the compatibility?
Yes it does.
Are there any known limitations on macOS, or is this likely just a
broken/misconfigured installation on my side?
Oh, now I get it. You are not building the network (bridge) driver. And
looking into meson.build I can see why:
# there's no use compiling the network driver without the libvirt
# daemon, nor compiling it for macOS, where it breaks the compile
if not get_option('driver_network').disabled() and
conf.has('WITH_LIBVIRTD') and host_machine.system() != 'darwin'
conf.set('WITH_NETWORK', 1)
endif
https://gitlab.com/libvirt/libvirt/-/blob/master/meson.build#L1649
But I'm not sure whether the comment is still true. I don't have any
access to macOS so I can't confirm nor deny. But since you can, you can
try changing that condition so that WITH_NETWORK is enabled and see
whether compilation fails. On the other hand, I'm not sure whether our
code would be able to talk to macOS and create briges/TAP devices/...
But unless you need something specific for RasPI (i.e. generic
HTTP/HTTPS) is enough, then you don't need libvirt network - you can use
<interface type='user'/>. You can even configure it's IP address should
you need to do so:
https://libvirt.org/formatdomain.html#userspace-slirp-stack
Michal