Originally posted by Creak
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AMD/Ryzen NPT Fix Discovered For Better Pass-Through Graphics Performance
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Originally posted by GraysonPeddie View PostI have a question concerning the GPU passthrough. How can I get my mouse and keyboard to interact with the VM without having a second USB mouse and keyboard? I tried using a keyboard-mouse switcher (a KVM without video) and switching back to the VM causes the keyboard and mouse to malfunction. I don't have Linux handy, but I remember that every time I unplug my mouse and keyboard, the ID number increments and I did not want that to happen. I'm at World Services for the Blind with only a Windows laptop as I'm getting certified in A+ and Network+, but my question about VM in Linux with PCIe passthrough still stands.
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Here is the original thread about this https://www.reddit.com/r/VFIO/commen...ssed_on_iommu/
Paolo (from RedHat) already made a official patch here: https://patchwork.kernel.org/patch/10027523/
For many years some users of assigned devices have reported worse
performance on AMD processors with NPT than on AMD without NPT,
Intel or bare metal.
The reason turned out to be that SVM is discarding the guest PAT
setting and uses the default (PA0=PA4=WB, PA1=PA5=WT, PA2=PA6=UC-,
PA3=UC). The guest might be using a different setting, and
especially might want write combining but isn't getting it
(instead getting slow UC or UC- accesses).
Thanks a lot to [email protected] for noticing the relation
to the g_pat setting. The patch has been tested also by a bunch
of people on VFIO users forums.
Fixes: 709ddebf81cb40e3c36c6109a7892e8b93a09464
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196409
Cc: [email protected]Last edited by vortex; 27 October 2017, 01:26 PM.
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Originally posted by GraysonPeddie View PostI have a question concerning the GPU passthrough. How can I get my mouse and keyboard to interact with the VM without having a second USB mouse and keyboard? I tried using a keyboard-mouse switcher (a KVM without video) and switching back to the VM causes the keyboard and mouse to malfunction. I don't have Linux handy, but I remember that every time I unplug my mouse and keyboard, the ID number increments and I did not want that to happen. I'm at World Services for the Blind with only a Windows laptop as I'm getting certified in A+ and Network+, but my question about VM in Linux with PCIe passthrough still stands.
BTW, Synergy is free. No need to pay unless you want their pre-compiled binaries. It's free as in GPL2.
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And suddenly current-gen Ryzen systems become viable for my use-case. I'll probably still wait from Zen+ or Zen2, but...... I might bet it now.
Originally posted by GraysonPeddie View PostI have a question concerning the GPU passthrough. How can I get my mouse and keyboard to interact with the VM without having a second USB mouse and keyboard? I tried using a keyboard-mouse switcher (a KVM without video) and switching back to the VM causes the keyboard and mouse to malfunction. I don't have Linux handy, but I remember that every time I unplug my mouse and keyboard, the ID number increments and I did not want that to happen. I'm at World Services for the Blind with only a Windows laptop as I'm getting certified in A+ and Network+, but my question about VM in Linux with PCIe passthrough still stands.
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Originally posted by Creak View PostI have an AMD FX CPU and an RX 480 GPU, I've tried to have GPU passthrough on a VM, but it didn't work. Could that bug be linked to my problem? Or it's simply that my setup can't handle GPU passthrough?
You saw the IOMMU enabled in dmesg?
See this tutorial https://heiko-sieger.info/running-wi...a-passthrough/
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Originally posted by vortex View PostHere is the original thread about this https://www.reddit.com/r/VFIO/commen...ssed_on_iommu/
Paolo (from RedHat) already made a official patch here: https://patchwork.kernel.org/patch/10027523/
Also answers my "who is Paulo ?" question from when the manager of our server BU SW team said they would "work with Paulo to get a proper fix".Last edited by bridgman; 27 October 2017, 07:13 PM.Test signature
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