[SOLVED] No internet in a Qemu VM

Didier Spaier · 12-08-2023, 05:10 PM

I have built and installed Qemu 7.2.1 in Slint64-15.0 based on Slackware64-15.0, using the SlackBuild from SBo without any modification or specific setting.

I can start a VM, but can't get a wired connection in it. This did not happen using Qemu 6.2., using the same script in both cases, example pasted below. I have tried using two VMs, in which I got a connection previously.

Code:

#!/bin/sh
qemu-system-x86_64 \
-cpu host \
-enable-kvm \
-boot menu=on \
-boot order=c \
-m 4G \
-device intel-hda \
-device hda-duplex \
-display gtk \
-vga std \
-drive if=pflash,format=raw,readonly=on,file=/data/qemu/firmware/OVMF_CODE.fd \
-drive if=pflash,format=raw,file=/data/qemu/firmware/OVMF_VARS.fd \
-fsdev local,id=vmdata,path=/data/,security_model=none \
-device virtio-9p-pci,fsdev=vmdata,mount_tag=data \
-drive file=/HD/bigfiles/fedora,format=qcow2,media=disk \
-cdrom /HD/images_iso_not_in_data/Fedora-Workstation-Live-x86_64-39-1.5.iso

I am wondering: do i miss an option to set up the network? However this was not necessary with version 6.2.

pghvlaans · 12-08-2023, 05:47 PM

The VM options look OK to me. A couple of ideas:

Try installing libslirp and building Qemu with BRIDGE_HELPER_SETUID=yes
What does /lib/udev/rules.d/65-kvm.rules look like?

ethelack · 12-08-2023, 07:03 PM

try adding (edit subnet as required)

-netdev user,id=n1,ipv4=on,ipv6=off,net=192.168.122.0/24,dhcpstart=192.168.122.6 -device virtio-net-pci,netdev=n1

AlleyTrotter · 12-08-2023, 07:26 PM

To enable user mode networking, install libslirp (availale on SBO), then
compile qemu:

Code:

SLIRP=yes ./qemu.SlackBuild

was the answer for me
HTH
john

chris.willing · 12-08-2023, 07:45 PM

From the qemu README,

Code:

To enable user mode networking, install libslirp (availale on SBO), then
compile qemu:

SLIRP=yes ./qemu.SlackBuild

edit: like AlleyTrotter said

zeebra · 12-09-2023, 12:19 AM

Quote:

Originally Posted by ethelack

try adding (edit subnet as required)

-netdev user,id=n1,ipv4=on,ipv6=off,net=192.168.122.0/24,dhcpstart=192.168.122.6 -device virtio-net-pci,netdev=n1

That's pretty much how my autogenerated VM network part looks too, or less specifically.

Code:

-netdev user,id=name -device virtio-net-pci,netdev=name

With id=id, being any id I guess.. And I just do the dhcp part inside the VM.

It shouldn't be necessary to install slirp manually, it's included as part of QEMU, I'm pretty sure. At least I never had to install it, and my QEMU "user" network works just fine.

Didier Spaier · 12-09-2023, 05:09 AM

Just setting SLIRP=yes worked, tried with two VMs, thanks all.

PS I forgot: Of course I first built and installed lislirp, and thanks to the SBo maintainers, contributors and admins. BTW everyone is welcome to take over the few scripts that still list me as maintainer though I abandoned them long ago.

chrisretusn · 12-09-2023, 06:53 AM

This thread has me thinking of finally giving Qemu a try. Been on my list for while. I'm using VirtualBox, primarily for testing with Slackware. The real show stopper for me is my Windows 10 VM, pretty sure I'd have to keep VirtualBox for that. Worried about loosing my Windows 10 activation if I was to switch to Qemu.

allend · 12-09-2023, 08:45 AM

Quote:

The real show stopper for me is my Windows 10 VM, pretty sure I'd have to keep VirtualBox for that. Worried about loosing my Windows 10 activation if I was to switch to Qemu.

You cannot transfer a VirtualBox Windows 10 to a QEMU Windows 10.
You can source a cheap license.

chrisretusn · 12-09-2023, 09:14 AM

Quote:

Originally Posted by allend

You cannot transfer a VirtualBox Windows 10 to a QEMU Windows 10.
You can source a cheap license.

Thanks!

Sigh... I suspected this. I don't use the VM but a few times a year anyway so not a big issue I was planning on keeping the VirtualBox install just for the Windows 10 VM. Everything else I use VirtualBox for I can just install in to QEMU.

Didier Spaier · 12-09-2023, 10:14 AM

However you can use all these image formats in qemu:
Supported formats: blkdebug blklogwrites blkverify bochs cloop compress copy-before-write copy-on-read dmg file ftp ftps host_cdrom host_device http https luks nbd nfs null-aio null-co nvme parallels preallocate qcow qcow2 qed quorum raw replication snapshot-access ssh throttle vdi vhdx vmdk vpc vvfat

So if your VirtualBox virtual drive is in one of these formats you can just re-use it in Qemu, just indicating its format in the -drive option.

PS The 'qemu-img convert' sub-command also allows to convert the virtual drive's format to another one.

Daedra · 12-09-2023, 12:02 PM

Quote:

Originally Posted by chrisretusn

This thread has me thinking of finally giving Qemu a try. Been on my list for while. I'm using VirtualBox, primarily for testing with Slackware. The real show stopper for me is my Windows 10 VM, pretty sure I'd have to keep VirtualBox for that. Worried about loosing my Windows 10 activation if I was to switch to Qemu.

You should definitely give it a try, I switched to Qemu/KVM last year and haven't looked back. And When you use virt-manager it is just as easy and straight forward as Virtualbox. Here is the sbopkg queue that I use to install it

Code:

osinfo-db-tools
osinfo-db
libosinfo
yajl
numactl
libvirt
libvirt-glib
libvirt-python
gtk-vnc
spice-protocol
spice
usbredir
spice-gtk
device-tree-compiler
libnfs
snappy
vde2
virglrenderer
libslirp
qemu
virt-manager

And speaking of the Windows 10 License, for the last 6 years I had been using the fifty or so left over Windows 7 keys I had to activate Windows 10. Microsoft finally closed that loophole two months ago, but you can find authentic Windows 10/11 keys all day long for around twenty or so dollars at places like g2a or even eBay.