IOMMU is enabled but not present

[EddieNahas]

Hi, I need help urgently with my Proxmox server
I had a complete power loss last night and when everything is recovered and I booted up my server again, all the VMs that have PCI devices pass-through didn't boot up giving error IOMMU is not present

I have checked all my config files and it shows that it is configured correctly



even demsg verification show that it is enabled


also I have checked my BIOS and verified that VT-d and VT-x is enabled

when I try to add a new PCI device to any VM it shows that IOMMU is not detected


my hardware is HP Z840 with dual Intel(R) Xeon(R) CPU E5-2695 v3 running Proxmox 7.0-11

any Idea what went wrong and how to fix it?

Regards,
Eddie

 

[leesteken]

Which method of booting are you using? GRUB, which uses /etc/default/grub or systemd-boot, which uses /etc/kernel/cmdline.
You can check which kernel parameters are actually passed with cat /proc/cmdline.
Don't forget to run update-initramfs -u after changes to the kernel parameters and/or configuration files in /etc/modprobe.d/
for d in /sys/kernel/iommu_groups/*/devices/*; do n=${d#*/iommu_groups/*}; n=${n%%/*}; printf 'IOMMU group %s ' "$n"; lspci -nnks "${d##*/}"; done is a nice way to check if IOMMU is working. It works when you see multiple groups and you can check which devices are properly isolated (no other devices in the same group except for PCI bridges)for PCI passthrough.