[coreboot] PCI passthrough on ASUS KGPE-D16

[Zoran Stojsavljevic]

> ...something that is above my paygrade.

@off topic:

Like (very much) this one (comment). Presently most companies try to
exploit your skills way above your paygrade, But when it comes to yearly
review, they go with whining and complaining about your performance in
actual paygrade. Well... Does not work on the long run (with smart R&D),
and it has its own Gaussian bell curve on the two-dimensional charts (x -
number of years with the company, y - value). It is very dangerous gambling
(I should say), managers and executives are doing (and mostly failing,
making catastrophic mistakes) these days! :-))
_______

I do not know too much about AMD, but this I know: to be able to support
IOMMU, you MUST have HW capabilities (in other words VT-d (INTEL), or IOV
for AMD). Essence: *IOMMU sounds like a generic name for Intel VT-d
<http://www.linux-kvm.org/page/How_to_assign_devices_with_VT-d_in_KVM> and
AMD IOV. In which case I don't think you can multiplex devices, it's a lot
like PCI passthrough before all these fancy virtualization instructions
existed :). SR-IOV
<http://blog.scottlowe.org/2009/12/02/what-is-sr-iov/> is different, the
peripheral itself must carry the support. The HW knows it's being
virtualized and can delegate a HW slice of itself to the VM. Many VMs can
talk to an SR-IOV device concurrently with very low overhead.*

Said/paraphrasing that... I have on my laptop VM F25 (beta pre-release).
Something which complies with SR-IOV (I already checked long time before. But
I use only BIOS on my laptop).

And, I have no idea what Coreboot is really supporting/up to:
[1] Pass-through (seems no SW/very light SW support needed)?
[2] SR-IOV (Single Root - I/O Virtualization - SW support heavily required)?

For this, Coreboot people should be capable (as I understand) to put some
light/clarify more on this topic.

Regards,
Zoran

On Thu, Oct 6, 2016 at 5:59 AM, Taiidan at gmx.com <Taiidan at gmx.com> wrote:

> I would really love to find a legit answer Re: what chipsets/mobos support
> gfx i/o fwd before I splash out hundreds of dollars.
>
>
> AFIAK forwarding graphics devices requires a lot more special sauce than
> regular pci devices (like network interfaces)
>
> On my propitiatory-firmware intel laptop dmesg says
> "DMAR: BIOS has allocated no shadow GTT; disabling IOMMU for graphics"
> So apparently you need a shadow gart for it to work, something that is
> above my paygrade.
>
> It would be really great if there was an IOMMU/GFX bit on the coreboot
> supported motherboards page as this is a common question that never finds
> anything more than anecdotal evidence. I am grateful for your help mike but
> running grep commands on the source files provides nothing more than just
> that.
>
>
> On 10/03/2016 07:09 PM, Mike Banon wrote:
>
>> Correct me if I am wrong, but I think: IOMMU support means that a
>> graphics card passthrough is possible (this is binary: IOMMU yes ==>
>> possible / no ==> not possible). If IOMMU support is buggy (which
>> seems to be commonly found with proprietary BIOS) maybe your system
>> could experience some bugs while you are using this feature. Of course
>> the most reliable way to find out is to try it, but I am pretty sure
>> that coreboot's IOMMU support is good
>>
>> On Sun, Oct 2, 2016 at 9:04 PM, Zoran Stojsavljevic
>> <zoran.stojsavljevic at gmail.com> wrote:
>>
>>> Would it be possible to passthrough a graphics card to a virtual machine
>>>> while using Coreboot/Libreboot?
>>>>
>>> Hello opteron/AMD supporter,
>>>
>>> You did ask very (very, should say extremely) tricky question, you do
>>> know
>>> this (I betcha you do, don't you)??? ;-)
>>>
>>> Zoran
>>> _______
>>>
>>> On Sun, Oct 2, 2016 at 6:22 PM, <opteron at keemail.me> wrote:
>>>
>>>> Hi,
>>>>
>>>> would it be possible to passthrough a graphics card to a virtual machine
>>>> while using Coreboot/Libreboot? The libreboot website says that the
>>>> motherboard offers full IOMMU-support when using a CPU from the Opteron
>>>> 6200/6300 series.
>>>>
>>>> https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF
>>>> https://libreboot.org/docs/hcl/kgpe-d16.html
>>>>
>>>> --
>>>> coreboot mailing list: coreboot at coreboot.org
>>>> https://www.coreboot.org/mailman/listinfo/coreboot
>>>>
>>>
>>>
>>> --
>>> coreboot mailing list: coreboot at coreboot.org
>>> https://www.coreboot.org/mailman/listinfo/coreboot
>>>
>>
>
> --
> coreboot mailing list: coreboot at coreboot.org
> https://www.coreboot.org/mailman/listinfo/coreboot
>
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