Comment 3 for bug 1863260

I have re-compiled gcc-9 from Focal after adding it to the list of releases which do not enable cf-protection by default. Then compiled Xen from Focal with that compiler. And it does boot!

# xen info
host : argabuthon
release : 5.4.0-14-generic
version : #17-Ubuntu SMP Thu Feb 6 22:47:59 UTC 2020
machine : x86_64
nr_cpus : 8
max_cpu_id : 15
nr_nodes : 2
cores_per_socket : 8
threads_per_core : 1
cpu_mhz : 2000.014
hw_caps : 178bf3ff:80802001:ee500800:000837ff:00000000:00000000:00000000:00000100
virt_caps : hvm
total_memory : 32766
free_memory : 29333
sharing_freed_memory : 0
sharing_used_memory : 0
outstanding_claims : 0
free_cpus : 0
xen_major : 4
xen_minor : 11
xen_extra : .4-pre
xen_version : 4.11.4-pre
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset :
xen_commandline : placeholder dom0_max_vcpus=4 dom0_vcpus_pin=true dom0_mem=3072M,max:3072M loglvl=all guest_loglvl=all hvm_debug=0 com2=115200,8n1 console=com2,vga
cc_compiler : gcc (Ubuntu 9.2.1-30ubuntu2+nocfprot1) 9.2.1 20200228
cc_compile_by : ubuntu-devel-di
cc_compile_domain : lists.ubuntu.com
cc_compile_date : Tue Mar 3 07:31:57 UTC 2020
build_id : e9eeb5132ed2948c175c17be4b1c47edded6d7be
xend_config_format : 4