[vfio-users] How to choose a compatible motherboard?

[Corey Larson]

Thanks for pointing that out.

Yes, it does not have an integrated GPU, but fortunately it has enough
slots that I can purchase a rather cheap GPU to drive the Linux side of
things in addition to my main one. It is more expensive, but seems to be
the most compatible based on the feedback I have gotten here.


On Thu, Oct 22, 2015, at 06:51 AM, Lucas Neves wrote:
> Hi Corey,
>
> I'm afraid that the E5-1620 V3 doesn't have an integrated GPU. I'm
> not sure though, since Intel simply omitted the "graphics
> specification" section from its page:
> http://ark.intel.com/products/82763/Intel-Xeon-Processor-E5-1620-v3-10M-Cache-3_50-GHz
> . So you would need a separate video card for your host system, if
> you want to use Linux as a desktop. That's why I chose the i5-4690k
> over a Xeon.
>
> For the record: my Radeon r9-285 by ASUS works with OVMF, but if I
> turn the guest off, I need to reboot the host. Guest soft-reboots
> are fine.
>
> I think that my ASUS Z87-PRO would yeald a proper IOMMU configuration
> if I had only one video card. But I also have an Nvidia GTX-660, that
> I use for the Linux host, and both the Nvidia and the ATI cards are
> put in the same IOMMU group. So I need Alex Williamson's patch to
> enable overrides for missing ACS capabilities. This patch creates DMAR
> problems that affect my Intel i915 HDMI audio, used by my wife's seat
> -- yes, I'm running KVM on top of a multiseat system. These DMAR
> issues are fixed by disabling IOMMU for the integrated graphics,
> booting with CONFIG_CMDLINE_LINUX=intel_iommu=on,igfx_off. Phew!
>
> Good luck! Lucas
>
>
> On Thu, Oct 22, 2015 at 10:42 AM Corey Larson
> <corey at eatrunco.de> wrote:
>> Thanks for all the help, everyone! I really appreciate it.
>>
>> So, to summarize and make sure I have condensed all this info
>> properly, the consensus seems to be that:
>>
>> 1. Current Skylake CPUs are a bad choice for vfio builds (because of
>> a  lack of ACS).  2. Xeon E5 CPUs are good. E3 and Core iX CPUs are
>> bad for vfio  (because of a lack of ACS).  3. Look for motherboards
>> that explicitly list VT-d as a feature. ASUS  boards seem to be
>> wonky. People seem to have good success with ASRock  boards.  4.
>> Configurations that rely on the ACS override patch may act weird,
>> and are less likely to be supported. Which makes sense given the
>> nature of the patch.
>>
>> As I was researching a build to leverage vfio, I did read AW's blog
>> posts, but had thought "Xeon? I'm not made of money!" After seeing it
>> pushed more on this list, I did more research and found that some of
>> the "entry-level" Xeons (specifically the E5-1620 V3) are very much
>> within the realm of regular people.
>>
>> Additionally, from those links to the HW lists, it seems that the an
>> ASRock (in my case, a X99 Extreme4 since its cheaper than the 6,
>> thanks for the pointer Nick) paired with a Xeon E5-1620 V3 is a
>> practical and cost effective solution.
>>
>> Thanks again!
>>
>> On Wed, Oct 21, 2015, at 11:26 AM, Corey Larson wrote:
>> > I am in a position where I can do a new build with this technology
>> > in mind. How do I go about picking a motherboard that will have the
>> > best compatibility to do vfio?
>> >
>> > Currently, my plan is to use this board:
>> > https://www.asus.com/us/Motherboards/H170-PRO-GAMING/specifications/.
>> > I plan to add an additional GPU (NVidia GTX 960) for the guest, and
>> > use the integrated Intel graphics to drive Linux. I also plan to
>> > make use of OVMF to avoid the Intel VGA arbitration patch.
>> >
>> > I appreciate any information you can share with me to help
>> > guide me!
>> > --
>> > Corey Larson corey at eatrunco.de
>> >
>> > _______________________________________________
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>>
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