Beancounter

Ok. THIS is how to successfully disable NPT on a Ryzen system: 1) Change the syslinux.cfg file to show: label unRAID OS menu default kernel /bzimage append initrd=/bzroot kvm-amd.npt=0 2) You will notice your windows VM will fail to load now. In order to get it to work properly you now have to go to the unraid GUI and click on VM's and shut down your windows gaming VM. Click edit and change the CPU mode from raw/physical to emulated (QEMU) . Thats it! I immediately noticed the CPU usage is higher but realistically jI can throw as many cores at this VM when I'm playing games as I want. Gaming FPS went from 10-25 to 60-140 in the same scene. WOOHOO!

Ok.... forget the /etc/modprobe.d/kvm-amd.conf file... Change the syslinux.cfg file to show: label unRAID OS menu default kernel /bzimage append initrd=/bzroot kvm-amd.npt=0 Trying this now. Will let you know how I make out.

I I had the same results as you. I was at work researching a solution for myself when I stumbled upon this thread. I added the following (which basically adds options kvm-amd npt=0 to kvm-amd.conf. echo "options kvm-amd npt=0" > /etc/modprobe.d/kvm-amd.conf I didn't notice any improvement so I putty'd back into the tower to see what other files were in /etc/modprobe.d. Sure enough there was a kvm.conf there as well. I added a line to the kvm.conf and rebooted the server just in case the server was only reading the kvm.conf and not the kvm-amd.conf. My understanding of the modprobe.d directory is minimal. I believe it runs any .conf files in that directory on boot and that file name does not matter (only what is contained within them). I didn't notice a difference either way. Quite frankly I don't know how to check that NPT is actually disabled. When I get the kids in bed I'm going to spend some time on this tonight. I'd gladly take a 20% hit on my CPU if it meant close to barebones GPU speeds.

I am experiencing the same issue. From the reading I've done the issue is with KVM. Xen passthrough has no issues on Ryzen. (correct me if I'm wrong) Disabling NPT in the gaming VM fixes the GPU issue (near barebones speed), but this obviously hinders CPU performance. How to disable NPT: https://forums.lime-technology.com/topic/36553-how-do-i-disable-nested-page-tables/ NOTE: I'm not sure which syntax is correct. I've noticed some people write "kvm-amd npt=0" while others use "kvm-amd.npt=0" For more info see: http://www.spinics.net/lists/kvm/msg152112.html https://forum.level1techs.com/t/ryzen-gpu-passthrough/116458 And updates on the VFIO/KVM issue: https://www.reddit.com/r/VFIO/