xen hypervisor allocated kernel memory conflicts with E820

[i27i13]

How to file a helpful issue

Qubes OS release

Qubes OS 4.2.0

Brief summary

My journey started here:
Details about my hardware (which is not on the HCL list)
https://forum.qubes-os.org/t/cannot-install-qubesos-always-booting-to-a-black-screen/22559/1
Progress begins at post #22 and over!
https://forum.qubes-os.org/t/cannot-install-qubesos-always-booting-to-a-black-screen/22559/22

Black screen regardless of which option I select when trying to install Qubes OS.
I had the issue with 4.1.2, but could finally successfully install when selecting:
Install Qubes OS R4.1.2 - Latest kernel
Press e to modify booting
On the line:
multiboot2 /images/pxeboot/xen.gz
add:
dom0_max_vcpus=16 dom0_vcpus_pin

I tried the same with 4.2.0, without any luck.
I also tried (on the second line): acpi=off nomodeset=0, without any luck :/

When booting & selecting:
Install Qubes OS
Test media
Troubleshooting

Editing & adding:
vga=,keep
I can see that the last two lines were (otherwise, just a black screen):
xen hypervisor allocated kernel memory conflicts with E820
(XEN) Hardware Dom0 halted: halting machine
Then the screen freezes, nothing becomes responsive, and I must manually restart the PC.

When booting & selecting:
Install Qubes OS - Latest kernel

The last 3 lines I get are:
(XEN) Freed 644kB init memory
about to get started…
(XEN) Hardware Dom0 halted: halting machine
Then the screen freezes, nothing becomes responsive, and I must manually restart the PC.

Steps to reproduce

Boot & select the right "USB"

Expected behaviour

Boot with the 64 threads and install without any faults!

Actual behavior

Black screen, but modifying the booting by adding:
vga=,keep
allows me to see the generated errors.

[walwan]

from the error message given by Xen, this looks like a Xen's memory allocation issue. U may report this to Xen upstream as well.

[i27i13]

from the error message given by Xen, this looks like a Xen's memory allocation issue. U may report this to Xen upstream as well.

How/Where do I do that? I am far away from being an advanced user :(

[marmarek]

This was already discussed on XenDevel matrix channel, we tried few things, but no any conclusion yet... A proper email to xen-devel mailing list would be useful.

[i27i13]

This was already discussed on XenDevel matrix channel, we tried few things, but no any conclusion yet... A proper email to xen-devel mailing list would be useful.

sorry, but with out an example, I could not do anything.
https://www.list.org/mailman-member/node41.html

I am far a way from being as capable as a "normal" person, and doing that little thing is something that I cannot do.
Thanks for the tip thoug :)

[byteit101]

I too have ran into this, though not involving qubes. I signed up for that list and sent an email regarding this issue. I have copied it below for reference:

To: xen-devel@lists.xenproject.org
Subject: E820 memory allocation issue on Threadripper platforms

Hi,

I ran into a memory allocation issue, I think. It is the same as 
https://github.com/QubesOS/qubes-issues/issues/8791 and I saw at the end it was 
recommended (by marmarek) that the issue reporter forward the issue to this list. 
I searched the list, but as I didn't see it in the list already, I'm doing that now.

Hardware:
I have an AMD Threadripper 7960X on a ASRock TRX50 WS motherboard. The Qubes reporter 
had a Threadripper 3970X on an ASUS Prime TRX40-Pro Motherboard. I saw a 3rd issue 
report of a similar issue on another Threadripper, so I think this may be Threadripper-specific.

Setup:
The QuebesOS reporter was using Qubes Installer.
My install was that I had a fresh install of Debian 12 (no gui), and then did 
`apt install xen-system-amd64` and rebooted.

The issue:
Any boot of Xen on the hardware results in a halted machine. When monitoring the logs 
with `vga=,keep`, we get:

(XEN) *** Serial input to DOM0 (type 'CTRL-a' three times to switch input)
(XEN) Freed 644kB init memory
mapping kernel into physical memory
about to get started…
xen hypervisor allocated kernel memory conflicts with E820
(XEN) Hardware Dom0 halted: halting machine

None of the settings I or the Qubes reporter have tried have been able to get past this failure.

I am happy to provide debugging support.

@i27i13 for future reference, you first send an email to xen-devel-request@lists.xenproject.org with a subject of subscribe, then it will email you back, and you click the link to confirm. After that is done, you are subscribed and you can just send an email to xen-devel@lists.xenproject.org