[coreboot] VT-d on Pixel 2015 (samus)

[Noah Vesely]

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

&%$#&%$#&%$#&%$#&%$#&%$#&%$#&%$#&%$#

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-samus-6300.B 
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/
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).

http://paste.debian.net/hidden/08ac8494/