[vfio-users] Hyper-v enlightments on recent NVIDIA drivers?

[Colin Godsey]

Qemu 2.5+ supports the hv_vendor_id flag that lets you change the vendor
ID. It was discovered that this is whats used by the nvidia drivers to
detect hyper-v, so changing the vendor ID allows you to use all the
enlightenments without upsetting nvidia

On Tue, Apr 12, 2016 at 4:51 PM thibaut noah <thibaut.noah at gmail.com> wrote:

> Hey guys, any news on that? More performances is always better, wondering
> if there are been some changes recently since it is a few months old
>
> 2015-12-05 18:04 GMT+01:00 Doug Applegate <doug.applegate at gmail.com>:
>
>> Hi!
>>
>> I got excited after hearing that the latest Nvidia driver doesn't
>> check Hyper-V. So I tried it on my Skylake Windows 10 VM using GTX970.
>> Unfortunately it doesn't work for me using Fedora 23 and stock qemu.
>> Windows reports the driver reports errors.
>>
>> I'm curious how you got it to work or where you read that it should.
>> I'm using nvidia driver version 359.06
>>
>> Thanks
>>
>>
>>
>> On Sat, Dec 5, 2015 at 4:21 AM, Eddie Yen <missile0407 at gmail.com> wrote:
>> >
>> >
>> > 2015-12-05 19:02 GMT+08:00 Ruben Torrero Marijnissen
>> > <ruben.torrero at gmail.com>:
>> >>
>> >> Hi,
>> >>
>> >> I installed last week a Windows 10 guest on my flaming new Skylake
>> >> build, on top of my Arch Linux install. After doing some reading, I
>> >> understood I had to disable any Hyper-V enlightment and make KVM run in
>> >> 'hidden' mode, so my Nvidia drivers wouldn't shut down.
>> >>
>> >> However, just for the curiosity, I googled for a while and found the
>> >> last version that didn't check for KVM presence and tested the
>> >> different performance with and without Hyper-V enlightments: Oddly,
>> >> Unigine benchmark doesn't show almost *any* performance gain, but with
>> >> several games, the difference can be as big as 50% in heavily loaded
>> >> scenarios. My guess on this games that rely more on the GPU won't see
>> >> much improvements, but games that also use I/O and CPU extensively will
>> >> see a big improvement. Any idea what other reasons there could be?
>> >
>> >
>> > IME, if you didn't add any signs in -cpu tag, or if you deleted any
>> Hvper-V
>> > signs in VM XML file, it will disabled Hyper-V functions.
>> >
>> > And, there are many games will got unstable performance without Hyper-V,
>> > especially online games and games that use a lot of mappings.
>> > I got huge performance differences on 3DMark tests. With Hyper-V, I can
>> got
>> > about 103xx, BUT i got only 95xx when I disabled Hyper-V.
>> >
>> > If Hyper-V checker has removed since newest driver, it's a good news,
>> but
>> > still need to test it.
>> > Also, some graphic cards only can use previous driver, especially using
>> in
>> > old OS.
>> >
>> >>
>> >> I also read in a forum (
>> https://lime-technology.com/forum/index.php?top
>> >> ic=43824.0) that Alex Williamson is working on a QEMU patch to allow
>> >> Windows guests to use Hyper-V enlightments without Nvidia beeing able
>> >> to detect is. Is this true?. Where could I follow the development /
>> >> test it?
>> >
>> >
>> > You can get that patch by downloading QEMU with git version.
>> >
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>> >
>>
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