Re: [coreboot] VT-d support

[Himanshu Chauhan]

> On 05-Jun-2017, at 10:19 PM, ron minnich  wrote:
>
> The reason I ask about what you need is that on chromebooks the main coreboot support came down to 'don't disable anything’.

I think its can’t just be disabled. Its just that kernel is not given any knowledge about its existence. This is what I want to know. The commercial BIOSes give an option of “enable VT-d” support. What do they do when this option is selected? Can this be implemented in Coreboot? This probably brings me to your next question of what is required. I would spend some time to figure that out.
> The DMAR requirements are not met on all platforms. But even after boot you can insert DMAR tables into kernels.
>
> So there is a key distinction between required support and desired support, and I wonder if you could figure out what is required and let us know what it is.

BTW, Do we have core boot tested on Intel’s Atom based C3xxx family SoCs?
> On Mon, Jun 5, 2017 at 9:39 AM Zoran Stojsavljevic  wrote:
> > what support does it need?
>
> Intel Virtualization Technology for Directed I/O" (VT-d). VT-d is a virtualized IOMMU, so by using HYP type 1 there should be a VT-d driver supporting VT-d HW extension (?), as my best understanding is
>
> The practical implications are Graphics and Network Connectivity in Guests. DMA Remapping is the feature of VT-d.
>
> Good net pointer to read: https://unix.stackexchange.com/questions/34428/do-virtualbox-or-vmware-use-t...
> > Is anybody working on this?
>
> Don't think so... If anything is done, I guess, it is done by simplistic implementation of the feature called: pass-through (so guest by its own drivers is using directly platform devices' HW bypassing HYP1, my best guess).
>
> Zoran
> On Mon, Jun 5, 2017 at 6:11 PM, ron minnich  wrote:
>
> On Mon, Jun 5, 2017 at 9:00 AM Himanshu Chauhan  wrote:
> Hi,
>
> VT-d requires support from BIOS. Does coreboot support VT-d?
>
> what support does it need?