The kernel for 8.8 introduced an issue for VMs running on Xen that makes it impossible to pause or migrate VMs in the xen pool.
It’s explained here, in particular this kernel patch: x86/xen: Split HVM vector callback setup and interrupt gate allocation - kernel/git/torvalds/linux.git - Linux kernel source tree
I have noticed that for rhel8.8 the latest kernel 4.18.0-477.21.1.el8_8.x86_64 does include the patch, while it is still missing in the same version on almalinux 8.8.
On almalinux:
[root@alma8 ~]# uname -a
Linux alma8.dkrz.de 4.18.0-477.21.1.el8_8.x86_64 #1 SMP Thu Aug 10 13:51:50 EDT 2023 x86_64 x86_64 x86_64 GNU/Linux
[root@alma8 ~]# grep xen.*vector /proc/kallsyms
ffffffff8e9e34f0 T xen_callback_vector
ffffffff8e9e3633 t xen_callback_vector.cold.25
ffffffff8f000fb0 T xen_hvm_callback_vector
ffffffff8f7fe810 r __ksymtab_xen_have_vector_callback
ffffffff8f8096af r __kstrtab_xen_have_vector_callback
ffffffff903b1030 D xen_have_vector_callback
on rhel8.8
[root@rhel8 ~]# uname -a
Linux rhel8.dkrz.de 4.18.0-477.21.1.el8_8.x86_64 #1 SMP Thu Jul 20 08:38:27 EDT 2023 x86_64 x86_64 x86_64 GNU/Linux
[root@rhel8 ~]# grep xen.*vector /proc/kallsyms
ffffffff9b7e4740 T xen_setup_callback_vector
ffffffff9b7e487e t xen_setup_callback_vector.cold.25
ffffffff9be00fb0 T xen_hvm_callback_vector
ffffffff9c5fe840 r __ksymtab_xen_have_vector_callback
ffffffff9c6096eb r __kstrtab_xen_have_vector_callback
ffffffff9d1b10f0 D xen_have_vector_callback
Where would be the place now to raise this issue?