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

[Jonathan Scruggs]

Search this email forum. Gerd posted a script you can use with libvirt.
It's in reply to my patch.
On 13 Apr 2016 21:18, "thibaut noah" <thibaut.noah at gmail.com> wrote:

> The problem i have is i use libvirt, putting the flag on qemu-arg requires
> to set cpu again.
> As i have no idea which cpu setting will be used this doesn't seem like a
> good idea, i saw that people use scripts apparently but i wonder if someone
> figured out how to put this directly into libvirt
>
> 2016-04-13 20:37 GMT+02:00 Colin Godsey <crgodsey at gmail.com>:
>
>> 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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>>>> > https://www.redhat.com/mailman/listinfo/vfio-users
>>>> >
>>>>
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>>>
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>
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