PCIe passthrough as root disk gets EFI disk / vars warning

[dirtyfreebooter]

i have 2 VMs with PCIe passthrough on a Xeon Gold 6326. Everything is great.

OPNsense PCIe passthrough

• Intel i350-t4 NIC
• NVMe disk

TrueNAS SCALE PCIe passthrough

• LSI controller
• NVIDIA GTX 1650
• Intel X710-da2 NIC
• 5x NVMe disks

i am installing the OSes on 1 of NVMe passthrough for each VM. if i ever need to go to bare metal, i can just remove the items as-is and move them to a new machine and it just works. don't even have to backup/restore configs.

the problem i am seeing is a warning about EFI vars because i don't have an EFI disk, which didn't seem to make sense for this type of install, but every time one of these VMs starts up, i get this warning

WARN: no efidisk configured! Using temporary efivars disk.

seems like i can safely ignore it, but wondering if i should have done something different with my setup/install?

this is a homelab, so i am more concerned with consolidating my setup to one machine for power and physical space. i have other VMs and LXCs that i run using standard volumes backed by the main ZFS pool from proxmox, so this setup really maximizes this one computer.

OPNsense

affinity: 0-7
agent: 1
balloon: 0
bios: ovmf
boot: order=hostpci0
cores: 8
cpu: host
hostpci0: 0000:05:00,pcie=1
hostpci1: 0000:8b:00,pcie=1
machine: q35
memory: 16384
meta: creation-qemu=7.1.0,ctime=1679624270
name: ring
numa: 0
onboot: 1
ostype: other
scsihw: virtio-scsi-single
smbios1: uuid=58024271-54e9-4cdf-8986-5472272f5dc5
sockets: 1
startup: order=100
tablet: 0
vmgenid: c4b297b5-5a9f-47a8-8297-ddbae6da3f1e

TrueNAS SCALE

affinity: 8-15
agent: 1
balloon: 0
bios: ovmf
boot: order=hostpci2
cores: 8
cpu: host
hostpci0: 0000:01:00,pcie=1
hostpci1: 0000:18:00,pcie=1
hostpci2: 0000:19:00,pcie=1
hostpci3: 0000:51:00,pcie=1
hostpci4: 0000:c3:00,pcie=1
hostpci5: 0000:c4:00,pcie=1
hostpci6: 0000:c5:00,pcie=1
hostpci7: 0000:c6:00,pcie=1
machine: q35
memory: 196608
meta: creation-qemu=7.1.0,ctime=1679196627
name: medina
net0: virtio=1E:7B:0D:12:CB:14,bridge=vmbr1,mtu=1
numa: 0
onboot: 1
ostype: l26
scsihw: virtio-scsi-single
smbios1: uuid=75f21115-784e-4c46-a3d3-aed843363917
sockets: 1
startup: order=200,up=45
tablet: 0
vmgenid: 63b231ba-c5a8-4f53-92d3-4fc953e8609a

 

[leesteken]

You're booting the VM with UEFI (by using OVMF) and that wants a place to store some settings (see also the Proxmox manual). UEFI settings would otherwise be stored inside a chip on the physical motherboard. That's what the EFI disk is for (it's not a virtual disk drive) and you should add it if you want to store the boot order.

 

[dirtyfreebooter]

oh that makes sense. adding them after-the-fact, both made the VMs unbootable with the pre-shared keys option checked (the default). removing those and re-adding EFI disk without the keys loaded worked great and no more warnings on startup!

 

[CRCinAU]

I just want to add to this - you don't need to add the EFI Disk if you don't want to use secure boot and your VMs disk has an 'EFI System Partition'.

It'll complain, but still boot properly.