Comment 27 for bug 1956166

Verification done for focal-proposed; all good!

See test steps in comment #14 and results below.

cheers!

Test environment:
================

$ hostnamectl status | grep Virtualization:
    Virtualization: kvm

$ lsb_release -cs
focal

$ sudo apt install --yes \
  xen-hypervisor-4.11-amd64 \
  linux-image-generic-hwe-20.04-edge

$ rmadison -a source -s focal-proposed xen
 xen | 4.11.3+24-g14b62ab3e5-1ubuntu2.2 | focal-proposed/universe | source

$ dpkg -s xen-hypervisor-4.11-amd64 | grep Version:
Version: 4.11.3+24-g14b62ab3e5-1ubuntu2.2

$ dpkg -L xen-hypervisor-4.11-amd64 | grep ^/boot
/boot
/boot/xen-4.11-amd64.config
/boot/xen-4.11-amd64.efi
/boot/xen-4.11-amd64.gz

$ ls -1 /boot/{vmlinuz,initrd.img}-5.15.0-*-generic
/boot/initrd.img-5.15.0-41-generic
/boot/vmlinuz-5.15.0-41-generic

$ ls -1 /boot/{vmlinuz,initrd.img}-5.4.0-*-generic
/boot/initrd.img-5.4.0-122-generic
/boot/vmlinuz-5.4.0-122-generic

Tests with 5.15 kernel: (problem fixed)
======================

Dom0 / Host:
---

 |*Ubuntu GNU/Linux, with Xen 4.11-amd64 and Linux 5.15.0-41-generic |
...
Loading Xen 4.11-amd64 ...
Loading Linux 5.15.0-41-generic ...
Loading initial ramdisk ...
(XEN) Xen version 4.11.4-pre (Ubuntu 4.11.3+24-g14b62ab3e5-1ubuntu2.2) ...
...
(XEN) Xen kernel: 64-bit, lsb, compat32
(XEN) Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x4000000
...
about to get started...
[ 0.000000] Linux version 5.15.0-41-generic ...
...

$ sudo xl info | head -n4
host : xen-f
release : 5.15.0-41-generic
version : #44~20.04.1-Ubuntu SMP Fri Jun 24 13:27:29 UTC 2022
machine : x86_64

DomU / HVM:
---

$ sudo xl create -c xen-5.15-vm.hvm
...
(initramfs) uname -rv
5.15.0-41-generic #44~20.04.1-Ubuntu SMP Fri Jun 24 13:27:29 UTC 2022
(initramfs) dmesg | grep DMI:
[ 0.000000] DMI: Xen HVM domU, BIOS 4.11.4-pre 07/28/2022
(initramfs) poweroff
...

DomU / PV:
---

$ sudo xl create -c xen-5.15-vm.pv
...
[ 0.000000] Linux version 5.15.0-41-generic ...
...

Tests with 5.4 kernel: (no regressions)
=====================

Dom0 / Host:
---

 | Ubuntu GNU/Linux, with Xen 4.11.4-pre and Linux 5.4.0-122-generic |
...
Loading Xen 4.11-amd64 ...
Loading Linux 5.4.0-122-generic ...
Loading initial ramdisk ...
(XEN) Xen version 4.11.4-pre (Ubuntu 4.11.3+24-g14b62ab3e5-1ubuntu2.2) ...
...
(XEN) Xen kernel: 64-bit, lsb, compat32
(XEN) Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x3a00000
...
about to get started...
[ 0.000000] Linux version 5.4.0-122-generic ...

$ sudo xl info | head -n4
host : xen-f
release : 5.4.0-122-generic
version : #138-Ubuntu SMP Wed Jun 22 15:00:31 UTC 2022
machine : x86_64

DomU / HVM:
---

$ sudo xl create -c xen-5.4-vm.hvm
...
[ 0.000000] Linux version 5.4.0-122-generic ...
...
(initramfs) uname -r
5.4.0-122-generic
(initramfs) dmesg | grep DMI:
[ 0.000000] DMI: Xen HVM domU, BIOS 4.11.4-pre 07/28/2022
(initramfs) poweroff
...

$ sudo xl create -c xen-5.4-vm.pv
...
[ 0.000000] Linux version 5.4.0-122-generic ...
...