[vfio-users] IGD passthrough on UEFI platforms

[Dmitry Fleytman]

> On 3 Jan 2018, at 16:05, Dmitry Fleytman <dmitry.fleytman at gmail.com> wrote:
> 
> 
> 
>> On 3 Jan 2018, at 16:00, Alex Williamson <alex.williamson at redhat.com <mailto:alex.williamson at redhat.com>> wrote:
>> 
>> On Wed, 3 Jan 2018 10:09:49 +0200
>> Dmitry Fleytman <dmitry.fleytman at gmail.com <mailto:dmitry.fleytman at gmail.com>> wrote:
>> 
>>> Hello All,
>>> 
>>> We're evaluating possibility of using IGD passthrough in legacy mode using Apple laptops, like Macbook Air as a h/w platform.
>>> 
>>> Apple laptops are using UEFI boot, according to lspci the options rom is disabled:
>>> [virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
>>> 
>>> As a result when trying to launch QEMU IGD passthrough, the following error is encountered:
>>> qemu-system-x86_64: -device vfio-pci,host=00:02.0,id=hostdev0,bus=pci.0,addr=0x2: IGD device 0000:00:02.0 has no ROM, legacy mode disabled
>>> 
>>> We tried to supply VBIOS binaries dumped from another platform with the same graphics adaptor, but that did not work either:  “legacy mode disabled” error disappeared but the picture did not show up on the screen.
>>> 
>>> Therefore, we would like to ask a number of questions:
>>> 
>>>  - What in your opinion would be the best way to make IGD passthrough working on hardware like this?
>>>  - For UEFI only OSes, like MacOS, what are the missing parts required to support UEFI VM with IGD passthrough?
>>> 
>>> Your thoughts are welcome,
>> 
>> You're on the right track with providing a ROM from another system, but
>> IGD ROMs don't typically "just work", try rom-fixer on it to fix the
>> device ID and checksum and make sure rom-parser reports a legacy ROM
>> section:
>> 
>> https://github.com/awilliam/rom-parser <https://github.com/awilliam/rom-parser>
>> 
>> I've made IGD assignment work on a UEFI Lenovo laptop by temporarily
>> booting a legacy OS, dumping the IGD ROM, booting back to UEFI, fixing
>> the ROM, then passing it to QEMU via the file option.  Thanks,
> 
> Thanks, Alex! We will try.


Hi Alex,

Thanks for your suggestion. We were able to boot Linux with IGD assignment successfully.

One more question - what about UEFI only OSes, like MacOS?

As far as I understand, such a configuration is not supported. Am I right?
What are the missing parts required to support UEFI VM with IGD passthrough?

Thanks,
Dmitry

> 
>> 
>> Alex

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