@olivierlambert it's for a rare usecase and we can wait for a proper fix

@olivierlambert Thanks a lot, the limitations of 128 cores and BIOS are fine for my usage.

@olivierlambert it works in BIOS mode. The system is Dell Poweredge R7625 with AMD EPYC

I can't go beyond 128 cores : xenopsd internal error: Xenctrl.Error("22: Invalid argument")

@olivierlambert Debian 12 template with PXE boot, local storage
Host has 2 x AMD EPYC 9534 64-Core Processor / 1.5 TiB of memory (24 x 64 GiB)

The issue comes from the number of CPUs, not the memory. I've made more testing. I've created some VMs from XOA 5.107.1 with template Debian Bookworm 12, PXE boot, local storage (EXT4)

no boot means console with "Guest has not initialized the display"
boot means : Tianocore logo and PXE boot

64x / 1 TiB => boot => upgrade to 128x => no boot
128x / 1TiB => no boot => downgrade to 64x => no boot
96x / 256 GiB => boot => upgrade to 102x => no boot => downgrade to 96x => no boot
97x / 256 GiB => no boot
99x / 512 GiB => no boot

There is a limitation of 96 cores, I've tried different CPU topology without any success

I'm using XCP-NG 8.3 on a DELL R7625 AMD EPYC Host. It has 1.5 TB memory, 128 CPUs (256 threads) and I try to boot a domU with 128 CPUs and 1TB of memory.

The DomU is created and started, I can see a 100% CPU usage on CPU0 but the console displays "Guest has not initialized the display (yet)."

Virtualization mode : Hardware virtualization (HVM)
CPU limits 128/128
Topology: 2 sockets with 64 cores per socket
Memory limits (min/max) Static: 1 GiB/1 TiB Dynamic: 1 TiB/1 TiB