xen 4.14/4.13 no pci passthrough since latest security updates

["D. Ziegfeld" <dzigg@xxxxxxxxx>]

Hello,

since the last update of the xen-package pci
passthrough isn't working anymore for me, but since i'm fairly new to 
xen i'm not sure if it is my fault or a new bug.
Compilation was successful with no errors.

I'm using a hvm-domU as driver domain (called: net-11) for my 
network-interfaces (wlan0 03:00.0/enp4s0 04:00.0).
If i start the domU(net-11) without any pci device it is fully working 
(except internet access ofc).
But the machine doesn't start if i try to atach a pci device either via 
config-file. also "xl pci-attach" doesn't work ("already assigned").
Can't connect to the vm via vnc.
Tried permissive mode also via grub/xl pci-attach, but same error.

Any help is appreciated.


Logs/information:

System: amd64 gentoo

uname:Linux myhost 5.9.3-gentoo-x86_64 #1 SMP Tue Nov 3 11:16:01 CET 
2020 x86_64 AMD Ryzen 5 3550H with Radeon Vega Mobile Gfx AuthenticAMD 
GNU/Linux
Xen: 4.14.0-r3 and 4.13.1-r5 (earlier versions all working)

"/etc/default/grub":
GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT="[...] 
xen-pciback.hide=(03:00.0)(04:00.0) xen-pciback.passthrough=1 [...]"
GRUB_CMDLINE_XEN_DEFAULT="console=none apic_verbosity=debug loglvl=all 
guest_loglvl=all"
"xl pci-assignable-list":
03:00.0 04:00.0

"xl list":
state of domU(net-11) is either running or no state at all. (switching 
within a second)

"/var/log/xenqemu-dm-net-11.log":
[...]
qemu-system-i386: relocate_memory 8192 pages from GFN 16000 to GFN f0000 
failed: Bad address
[...]