I have been attempting to do hardware passthrough where I pass my Intel ARC GPU through to a Ubuntu Server VM, and two Sata HBAs to a separate Truenas Scale VM. One or the other works fine, but if I attempt to start both VMs with the passthroughs enabled the whole host locks up. This also happens even if I select just one of either SATA HBAs so it does not appear to be specific to the HBA Model.

The GPU is in PCI_E1 which is the CPU driven PCIE Slot. The HBAs are in one pcie X1 slot and one m.2 slot (which should be chipset).

This is an install I upgraded from 8 to 9, and have been tempted to rollback to 8 to see if that helps things but I know 8 is EOL soon. The GPU passthrough worked on 8 but I did not attempt the HBA passthrough until 9.

All three devices (including both ARC device IDs) are using VFIO, everything is in their own IOMMU group, the passthroughs have no issue working individually.

the setup:
MSI - Pro Z690-A Motherboard
Intel i5 12400F
48 GB DDR4 memory
Intel Arc A380 GPU
512 GB NVME drive for host install
Sata HBA1 - Marvell 88SE9215 PCIe 2.0 x1 4-port SATA
Sata HBA2 - ASMedia Technology Inc. ASM1166 Serial ATA Controller

Proxmox Version 9.2.3
Linux Kernel 7.0.6-2