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Play games in Windows on Linux! PCI passthrough quick guide

iommu
vfio
passthrough

#82

Are you just replying to random posts?

Yes OVMF works on Ubuntu but it is easier and has better support on Debian. Not to mention you don't have to update it manually.


#83

I had a similar problem the solution I did to get it working was to use chipset I440FX instead of Q35 also in the VM remove the Basic Microsoft Video Driver then install AMD Video Driver. Hope it helps :p


#84

I'm trying to recompiling my kernel since i now need the ACS patch since I added a new GPU for my Linux host and is in the same iommu groups as my VM GPU. Here a screenshot of my terminal for the error BTW thanks for the KVM guide.


#85

Looks like you need gcc > 4.9.

if not search around. Haven't seen that error before.


#86

I check what version of gcc i have installed and it version 6.2.0 what version did you had install when you patch your kernel.


#87

I'm not sure but I know it was over that version.

I would just search around and see what you can find, I'm not going to Google for you. ;)


#88
  1. I don't reply to random posts, I reply to posts I have an answer to
  2. Even with real motherboards, when do you really need to update the UEFI? Only when something doesn't work, I haven't re-downloaded mine since I first downloaded it.

#89

Hunh? When did we start talking about updating UEFI?

Unless you are talking about OVMF which you should update when a new one is available. Redhat is always releasing security updates and feature improvements to KVM which you should always use. There was a nasty KVM leak discovered a while back that would allow a VM to read the host's RAM. Whether it is OVMF or KVM or whatever you should always update when you can, and using the pre-built package is easier. Just seems simpler to me since I already use Debian.


#90

I have some questions about usability that's not real clear to me.

Does this KVM run like standard VM's and only run when you want?
If so can the host use the second GPU when the VM is not in use?

I'm curious about switching the KVM on and off a few times throughout the day and how well Linux handles it.


#91

it isn't ? I'm not using using debian so I am looking a the debian packages search and the distro appears to have 2.4 version unless I'm reading wrong.

Because of your tutorial I tested libvirt again instead of qemu and got it working however, I used the parameter that @Celmor mentioned on his reply because according with to archlinux wiki the kvm=off degrades performance substantially, so if you can upgrade the packages you might want to try out.

Anyway, thanks for the great tutorial.


#92

it degrades performance? How? Can you show us a benchmark, I'd be very interested to see.

From what I read that parameter only changes how the VM sees the host, it doesn't actually turn virtualization acceleration off.


#93

If you have an AMD card then there is a way to hot-swap the GPU between the host and the VM but it is messy.

For Nvidia you have to reboot to make this happen as well as switch your primary display output back to the GPU. More hassle than it is worth if you ask me.

PCI passthrough is best done with 2 GPUs if you want GPU acceleration on the host as well.


#94

Like I said, according the archlinux wiki page.

I only got it working virt manager yesterday so I hadn't time to do any kind of tests and I only pointed out since you mentioned you are working on a video with benchmarks.


#95

Can you link me to where you found that about the performance hit?

All I see is a mention of using kvm=off to hide the host from the VM.

https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF


#96

ok, I must say I'm embarrassed and made a mistake and its the only the hyper extensions not that particular parameter.

I read several qemu examples with both the hyper extensions disabled and kvm=off parameters and ended mixed them up believe that parameter would also penalize performance.

Sorry the the misleading answer.


#97

No problem dude, I'm not an expert either.


#98

I'd like to add that a have fix the problem i had early in this tread so here the solution https://ubuntuforums.org/archive/index.php/t-2314877.html disable fstack then disable PIE-Mode http://askubuntu.com/questions/851433/kernel-doesnt-support-pic-mode-for-compiling/851747.

No i want to know if you have seen this error when compiling @GrayBoltWolf


#99

You didn't screenshot the error.


#100

Isn't this the error at the last 4 line

scripts/package/Makefile:91: recipe for target 'deb-pkg' failed
make[1]: *** [deb-pkg] Error 2
Makefile:1333: recipe for target 'deb-pkg' failed
make: *** [deb-pkg] Error 2

I open my .conf files and check what on line 91 and it this CONFIG_GENERIC_IRQ_CHIP=y


#101

That part at the end means the entire build failed, the actual error is further up. if you run it with make -j1 then you will see the error at the end.