XEN

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XEN Distributions

2003 Xen Project University of Cambridge https://xenproject.org/ https://xenbits.xen.org/gitweb/
2007 Citrix XenServer Citrix acquired XenSource
2010 XCP (Xen Cloud Platform) Citrix opensource (hypervisor + management)
2018 XCP-ng forked from XCP after citrix restrictions.

Xen API (XAPI) / Xen Orchestra

https://xenproject.org/projects/xcp-ng/
2022 XenServer Citrix https://www.xenserver.com/story


XEN is a kernel, booted by GRUB, which can then boot a Linux kernel as Dom0. The first operating system that can control the XEN kernel and boot a privileged virtual machine as DomU. VM's are called domains, which have a name and an id. On the DomU (host), XEN can be controlled on the DomU with the command xe, xm or xl depending on the Xen version. The unprivileged vm's are named Dom0

xl info

xl create /etc/xen/win.hvm

xl list

xl destroy 2


XEN can use Fully Emulated HVM from real devices (VIF-EMU), which can use the default OS drivers, by emulating the hardware. The interface will appear as vif25.1-emu on the host.

XEN can also use PV paravirtualized devices (VIF) that use drivers to talk directly to the XEN backends (e.g. XENQEMU). The VIF number corresponds to the domain

vif25.0

Drivers are part of the Paravirtualized Tools for XEN

https://wiki.xenproject.org/wiki/Xen_Networking

https://xenbits.xen.org/docs/unstable/man/xl-network-configuration.5.html

https://xenproject.org/resources/downloads/

https://github.com/xcp-ng/win-pv-drivers/releases

Alpine Linux

Alpine Linux downloads come with a XEN ISO that can be used, but using a regulare version can also run XEN

https://wiki.alpinelinux.org/wiki/Xen_Dom0

setup-xen-dom0
apk add xen-hypervisor
apk add bridge
apk add seabios ovmf
echo "xen-netback" >> /etc/modules
echo "xen-blkback" >> /etc/modules
echo "tun" >> /etc/modules
rc-update add xenconsoled
rc-update add xendomains
rc-update add xenqemu
rc-update add xenstored

Contents of /etc/default/grub

GRUB_CMDLINE_XEN_DEFAULT="dom0_mem=1024M,max:1024M" GRUB_DEFAULT="saved" GRUB_SAVEDEFAULT="true"
grub-mkconfig -o /boot/grub/grub.cfg
grub-set-default "$(grep ^menuentry /boot/grub/grub.cfg | grep Xen | cut -d \' -f 2 | head -1)"

efibootmgr -c -d /dev/sda -p 1 -l /EFI/boot/xen.efi -L "XEN"

efibootmgr -o 2,0,4

https://wiki.xenproject.org/wiki/Xen_EFI

https://wiki.archlinux.org/title/xen


https://xcp-ng.org/docs/architecture.html#api

PCI passthrough was indeed necessary for the software I'm using to pick up all network traffic properly (not bridging through the virtual switch). Doing so requires enabling IOMMU and using the legacy linux bridge backend networking (instead of the default Open vSwitch backend networking).

xl network-list opnsense
Idx BE Mac Addr. handle state evt-ch tx-/rx-ring-ref BE-path 
0 0 00:16:3e:3f:4f:61 0 5 -1 -1/-1 /local/domain/0/backend/vif/11/0

https://xenbits.xen.org/docs/4.15-testing/man/xl-network-configuration.5.html

https://wiki.xenproject.org/wiki/Device_Model_Stub_Domains

type=ioemu
vifspec
model=e1000
rate=10Gb/s
vif = ['bridge=lan,model=e1000,rate=10Gb/s']
device_model_stubdomain_override