Wireless with QEMU/KVM

[issinoho]

Simple question: does using the wireless connection from a Linux QEMU/KVM support networking on a x86 VMS guest? I've been using a hard ethernet connection but it would simplify my setup to get rid of that - I recall older AXP emulators were NOT happy with wireless as a general rule of thumb. TIA.

[cct]

From the VMS 9.2-2 release notes:

2.2.4. DECnet Over Wi-Fi
DECnet Phase IV will not work over a Wi-Fi connection. To be able to use DECnet Phase IV on an x86-64 virtual machine and communicate with other systems, you must have the host machine connected via an Ethernet cable.

DECnet Plus will work over a Wi-Fi connection, but it must be tunnelled through TCP/IP.

[issinoho]

To give more context, I'm running QEMU/KVM on a Debian host and the IP stack of the host is as follows.

Code: Select all

$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
3: wlo2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
6: macvtap2@eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 500

eno1 is cabled Ethernet; wlo2 is wireless. Both are connected.
That 4th device is created by the hypervisor depending on which Macvtap network source is chosen in the OpenVMS guest NIC configuration. In the above, OpenVMS is running over the cabled device and this works perfectly with TCP/IP services (DHCP).
Changing to the wireless source in the NIC configuration replaces the Macvtap device with the wireless equivalent however the OpenVMS guest TCP/IP refuses to work over the link (tried both DHCP and static).

So I guess my question here is, should this work? And if so, what should I be looking at?

[arne_v]

I am curious about what the problem is.

The two setups are:

wire--Linux wire driver[Linux driver API]--VM emulating some NIC--VMS driver[VMS driver API]--VMS application
wireless--Linux wireless driver[Linux driver API]--VM emulating some NIC--VMS driver[VMS driver API]--VMS application

Why does the physical network and the Linux driver matter for VMS?

[jonesd]

I can only get Phase IV to work on VirtualBox if I explicitly configure the NIC to be the DECnet link address (AA-00-04-00-xx-xx) that matches the system ID as the NIC emulators on the seem to support letting the guest set it. Do wi-fi adapters not allow setting the mac address under any circumstances?

BTW, just bought a USB ethernet dongle to plug into my laptop so that the VMS VM has a dedicated ethernet port to the network.

[dmjb]

Simple question: does using the wireless connection from a Linux QEMU/KVM support networking on a x86 VMS guest? I've been using a hard ethernet connection but it would simplify my setup to get rid of that - I recall older AXP emulators were NOT happy with wireless as a general rule of thumb. TIA.

On my Laptop, I run VMS on top of KVM, and I am able to connect to the internet from VMS over the laptop's Wifi connection. I use the NAT virtual network as my source instead of Macvtap or a bridge device.

The main caveat with Wifi is that you typically cannot set up a bridged connection to give your VMS virtual machine its own IP address on the network. There are sometimes workarounds, but you are much better off using a wired ethernet connection if you need to connect to the VM from outside of your laptop.

[issinoho]

@arne unfortunately it does seem to make a difference in the real world;
@dmjb that's a good point, and I suspect you are correct here regarding NAT vs Bridged - I will test with NAT over WiFi to satisfy my own curiosity.