[SOLVED] Assigning second PCI NIC port causes VM crash

JayB21

New Member
Apr 12, 2025
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I have an intel x540 at2 2 port 10gbps NIC in my proxmox system running 2 pfSense VMs

lspci at the PM console shows

06:00.0 Ethernet controller: Intel Corporation Ethernet Controller 10-Gigabit X540-AT2 (rev 01)
06:00.1 Ethernet controller: Intel Corporation Ethernet Controller 10-Gigabit X540-AT2 (rev 01)

so I assume that's as expected.

I've added the PCI 06:00.0 NIC to the 1st VM and PCI 06:00.1 NIC to the 2nd VM.

I start VM1 and everything works fine. But when I start VM2, things hang for a few minutes and then VM1 goes offline. If I try to start VM1, after that, things hang and then VM2 goes offline. Note: Both work just fine at the same time with virtual NICs.

Obviously some kind of conflict with the card but I'm not sure what to do. I did see a post at proxmoxcentral that suggested adding iommu entries in grub for intel NICs

GRUB_CMDLINE_LINUX_DEFAULT=”quiet intel_iommu=on iommu=pt pcie_acs_override=downstream video=efifb:off”

But that didn't seem to do anything.

UPDATE: A few minutes after posting this I found a thread on PCI RAM locking. I reduced the ram for both of the VMs from 8gb to 4gb and they both ran fine.
 
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