@maximsachs Thanks for getting back to me on this.
I think (and hope) that in the mean time we will have released an official new ISO that fixes the issue you are having.
So, you will be better off testing the new official ISO rather than this unofficial one 
I'll try to ping here when the new official ISO is out.
Thanks!
Regards,
Yann
@gleveque Hello
Can you retry with an up-to-date XCP-ng 8.3 host?
PCI expansion ROM are now enabled when doing pass-through.
The guest VM can now access the ROM bar.
Regards,
Yann
Hello @mgr42
I can confirm that indeed today AMD iGPU passthrough is not working on XCP-ng.
I am currently (slowly) working on it.
There are other references about this topic in the Forum and on GitHub FYI:
On the setup I am working on, the Expansion ROM is provided indeed by firmware via the VFCT ACPI table.
I dumped it to a file and provided it to qemu-dm xen-pci-passthrough device via the romfile= argument (via a modified XAPI build).
I can now indeed see a ROM bar in the guest but unfortunately its content is not the content of the file therefore nothing works (amdgpu driver is unable to get its ROM and fails).
So now I'm debugging qemu to try to understand the issue with the emulated/passed-through ROM BAR.
Regards,
Yann
Kernel & Hypervisor team
@yllar I'm not sure, maybe it'll slip to July.
But what I can say is that the ISO is currently being tested in our QA process.
Brace yourself, it's coming soon
@yllar @mik @Pilow @marcvds Hello, we think we now understand better this issue.
We think it's a Xen issue with regard to PCI devices on segment 0001 (which is your case) and not a dom0 driver issue.
Could you give a try to this ISO installer please?
Please note that this is a custom test ISO and it is therefore not officially supported, do not use it for production, it is just to confirm that it fixes your issue, we will release a supported ISO in the future (target date for now is June).
unsupported test ISO for you to test: https://nextcloud.vates.tech/index.php/s/iHf8sqq39EqE683
Regards,
Yann
Hello @codemercenary
In theory Xen is NUMA aware (See https://wiki.xenproject.org/wiki/Xen_on_NUMA_Machines) so you would leave memory interleaving option of the BIOS off so that Xen does what it thinks is necessary.
But these kinds of settings are very very workload sensitive and in fact it's usually a good idea to just test what works best for you.
Regards,
Yann
FYI this is not being forgotten, we still have a card about this assigned to someone, it will just take a bit more time than I thought before we work on this.
I'll send updates here when we have new elements.
Regards,
Yann