[CentOS] intel_iommu=on => No root device found
ncaspar at me.com
Tue Jan 29 21:16:45 UTC 2013
for some reaseon, my message wasn't published. Second try, this time without the giant attachment.
I have an Intel server (SR2600URBRPR) in front of me. The disks in my server are connected via PCI card (Adaptec RAID 3405).
Now I would like to passthrough a PCI-E graphics card to a KVM guest. As this requires Intel VT-d, I configured the following options in the BIOS:
Intel VT for Directed I/O [Enabled]
Interrupt Remapping [Enabled]
Coherency Support [Disabled]
ATS Support [Enabled]
Pass-through DMA Support [Enabled]
Everything works so far, but when I add intel_iommu=on to the kernel line of my grub.conf, Dracut gives my a kernel panic while booting. I added "rdshell" to the command line and extracted the boot messages via dmesg (http://nilscaspar.ch/centos-dmesg.log). I think the main problem is this:
dracut Warning: No root device "block:/dev/disk/by-uuid/280234d1-dff5-4e04-b1ef-93d54cdcd825" found
But I doesn't make sense to me... As soon as I remove intel_iommu=on, everything works again (except the passthrough :P).
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