I've been trying to get VT-d working on John Lewis's build for the 2015 Pixel (samus). You can see our conversation at https://plus.google.com/116173342884039282107/posts/TGA4EXYQMfq and I have also pasted it below. So far, I haven't got anywhere, so I thought I would try asking you all as well.
Thanks, Noah
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Noah Vesely - Jul 16, 2015
Is it possible to get Intel VT-d working on the Chromebook Pixel 2/ Samus? The i7-5600U processor does support it. ARK | Intel® Core™ i7-5600U Processor (4M Cache, up to 3.20 GHz) ark.intel.com ARK | Intel® Core™ i7-5600U Processor (4M Cache, up to 3.20 GHz) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more. John Lewis's profile photoNoah Vesely's profile photo 10 comments John Lewis Jul 18, 2015
AFAIK, none of the hardware VT extensions are disabled in the firmware on Samus. Have you tried it? Noah Vesely Jul 18, 2015
Yes. VT-x was enable while VT-d was not. John Lewis Jul 18, 2015
Clone https://chromium.googlesource.com/chromiumos/third_party/coreboot/+/firmware... and run menuconfig to see if there's an option for VT-d. Noah Vesely Jul 19, 2015
I can't figure out how to checkout this repository. I cloned the main third_part/coreboot repo then checked out the broadwell branch, but could not find the same directory you linked. Maybe my git fu could use some work. John Lewis Jul 20, 2015
Use the last chunk of the URL as the branch argument i.e. "-b firmware-samus-6300.B". Noah Vesely Jul 20, 2015
Nothing in menuconfig, however, I found the line `#define CONFIG_IOMMU 0` in ./build/config.h. I also found `#define CONFIG_ENABLE_VMX 0`. John Lewis Jul 21, 2015
VMX is already enabled in the firmware. IOMMU is unrelated. I would have to conclude that VT'd is either not supported by that CPU or something more needs to be done in coreboot to get it to work. Noah Vesely Jul 21, 2015
VT-d is supported by this CPU. See original link to Intel Ark.
VT-d is Intel's specification for their IOMMU technology, so I don't see how it's unrelated. John Lewis Jul 21, 2015
Take a look at the .config from a shellball ROM (you can extract it using cbfstool).
https://johnlewis.ie/extracting-the-shell-ball-rom-using-a-chromeos-image/%E... Noah Vesely 9:15 PM
I don't see anything relevant to VT-d; no VT-d keywords (e.g., iommu, vt, vmx, hvm, and directio).