intel_iommu and HP servers?

[underslung]

Does anyone have this working? I'm trying to set up PCI passthrough on an HP DL360 G6 and passing the intel_iommu=on paramater via grub causes the console to be flooded with DMAR errors and the machine never finishes booting. Passing intel_iommu=igfx_off will let the machine boot but all of the device entries in dmesg look like this:

DMAR: Device scope device [0000:00:1a.00] not found

The processors are Xeon E5504 which do support VT-d. Is this perhaps iLO being problematic?

 

[PigLover]

Check your BIOS settings. VT-d support is configurable in the BIOS and almost every HP server I have ever dealt with has this default "off". Dell servers too.

 

[underslung]

Sorry, I should have mentioned that VT-d is indeed enabled in the BIOS. The only way to get the machine to boot once the intel_iommu=on option is set in grub is to turn VT-d off in the BIOS. Then I can change the parameter to intel_iommu=igfx_off or intel_iommu=pt and re-enable VT-d in the BIOS and the machine will boot, but then all I get in dmesg is the

DMAR: Device scope device [...] not found

for everything on the PCI bus.

I've also updated the BIOS and firmware.

Check your BIOS settings. VT-d support is configurable in the BIOS and almost every HP server I have ever dealt with has this default "off". Dell servers too.

 

[underslung]

Just an update in case anyone else is running into this problem, I believe that VT-d is just broken in the kernel for this hardware. I tried a couple other distros with the same results. I sort of got it working in Xen but that was kludgy so I went with ESXi, which works out of the box, but now I have to use Winders to manage it. Boo.