> ...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 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 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@gmx.com <Taiidan@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@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@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

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