Re: [Xen-users] AMD-Vi/Intel VT-d: Passthrough or virtualization?

[Nick Khamis <symack@xxxxxxxxx>]

There was no way I was going to pass on this conversation, even with
my busy schedule.

>> This means that if you only have a single Video Card, you potentially will 
>> lose
>> video output for anything but that VM. Best setup seems to be an integrated 
>> Video Card
>> like the one that most Processors currently got to handle the Hypervisor + 
>> other VMs with
>> the standard emulated VGA Drivers plus a discrete Video Card for the gaming 
>> VM.

My understanding was that this relied on the number of Virtual
Functions a PCI device was equipped with in the firmware. This at
least is the case for network cards...

Not to chase tails here however, can we step back and figure out which
of the chipset manufactures (AMD vs. Intel) provides a stable platform
that can be used in production. We are not necessarily interested in
GPUs but we are interested in passing through network cards QLogic,
Intel etc... I would imagine this would still be important to the
gamers, and Justin.tv broadcasters as well....

Secondly, are any of the manufactures such as IBM and DELL openly
pushing stable virtualized platforms (chipsets, pci bus, cpus, bios),
that we can again run in a production. And of course, there should be
XEN compatibility on top of all this...

We can understand why the chipset, cpu, and even pci hardware
manufactures would play this cat and mouse game with virtualiztion
since to them it equates to less sales......

>> Casey DeLorme
>> From my experience if VT-d or IOMMU are not explicitly mentioned in the user 
>> manuals >> (available for download off the net before you spend a dime on 
>> the board) then it likely
>> does not have support for it.

Interesting... We do something similar when purchasing IBMs. We look
to see if there are BIOS firmware updates that involve virtualization
such as this:

http://www-947.ibm.com/support/entry/portal/docdisplay?lndocid=MIGR-5086623


I came in a little late in the game for this conversation however, can
we please iron out some issues here. At an abstract level (i.e.,
chipsets, cpus, gpu, network interfaces), without mentioning any
motherboard manufactures such as ASRock, Asus, Saphire etc.. can we
determine which combination will work. Both on the AMD and Intel
platform. The reason for this is because not too many people deploy
white boxes for production. it's strictly SuperMicro, IBM, Dell etc...

Once determining this, it would be nice to discuss which of the
manufactures are able to support stable platforms without rendering 3
out of the 4 PCIe/x slots useless. This would hurt!

We also need to keep it fairly modern. For example, PCIe slots would
preferably be PCIe v2 x8/x16 PCIe v3 x8/x16. For example, I mentioned
IBM enabled virtualization server however, what I am really looking at
are the guts. For example:

Intel Based (x3550 M4)
CPU: E5-2600
Chipset: Intel C604

All PCIe slots are PCIe 3.0
Slot 1: PCIe x16; low profile, half-length
Slot 2: PCIe x8, opt. PCI-X or PCIe x16; full-height/half-length (PCIe
x16 req. 2nd CPU)

I am actually not sure if this platform support virtulaization since
the little bit of googling did not yield much.

AMD Based: x3755 M3
CPU: AMD Opteron 6200
Chipset: SR5690

All PCIe slots are PCIe 2.0

Slot 1: PCIe x16, full height, full length
Slot 2: PCIe x8, low profile, half length
Slot 3: PCIe x8 (x4 wired), low profile, half length
Slot 4: PCIe x8, low profile, half length (internal only, reserved for RAID cont

This machine I think does support IOMMU passthrough at the bios level
since there has been firmware updates for it:

http://www-947.ibm.com/support/entry/portal/docdisplay?lndocid=MIGR-5086623


Buying hardware just got a lot more trickier folks, let's hope this
thread can shed some light on our lost souls, and make us complete
again....

Kind Regards,

Nick.

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