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Uhoh this kind of removes one of the things holding me back from buying - """The last addition should excite those interested in virtualization. AMD has announ

Uhoh this kind of removes one of the things holding me back from buying - """The last addition should excite those interested in virtualization. AMD has announced "fresh support" for PCI Express Access Control Services (ACS), which enables the ability to manually assign PCIe graphics cards within IOMMU groups. This should be a breath of fresh air to those who have previously tried to dedicate a GPU to a virtual machine on a Ryzen system, since it has thus far been fraught with difficulties.""" People have been fairly successful over the years combining their windows games box into their linux workstation by doing this. I haven't dipped in but I am pretty tempted. Can anyone comment on the stability of the linux workstation if the windows vm takes a dump via bad drivers etc? That's my concern is that my linux workstation is highly highly stable and I don't want to borrow problems just to save a box.

kbwt 9y ago
You might want to hold out until AMD gets the "Nested Page Tables" issue fixed. It's supposed to speed up virtual memory handling in the guest by avoiding the need for shadow page tables and/or emulation by the host. Currently the feature is broken, resulting in crippled GPU performance, allegedly due to the IOMMU not keeping up with the DMA transaction rate. You can disable it entirely (kernel command line amd-kvm.npt=0) at the cost of ~5x increased CPU usage and constant stuttering in games, which is what most people choose to do for now.
- hammerandtongs 9y ago
  Hah! Well that will help me push this project off for a few months more :) Is there a good spot to keep up with this, that is very linux focused?
  - kbwt 9y ago
    https://www.reddit.com/r/VFIO/ https://www.reddit.com/r/VFIO/ and https://www.redhat.com/archives/vfio-users/ https://www.redhat.com/archives/vfio-users/
    - hammerandtongs 9y ago
      Brilliant, thank you.

kbwt 9y ago

You might want to hold out until AMD gets the "Nested Page Tables" issue fixed. It's supposed to speed up virtual memory handling in the guest by avoiding the need for shadow page tables and/or emulation by the host. Currently the feature is broken, resulting in crippled GPU performance, allegedly due to the IOMMU not keeping up with the DMA transaction rate. You can disable it entirely (kernel command line amd-kvm.npt=0) at the cost of ~5x increased CPU usage and constant stuttering in games, which is what most people choose to do for now.

hammerandtongs 9y ago
Hah! Well that will help me push this project off for a few months more :) Is there a good spot to keep up with this, that is very linux focused?
- kbwt 9y ago
  https://www.reddit.com/r/VFIO/ https://www.reddit.com/r/VFIO/ and https://www.redhat.com/archives/vfio-users/ https://www.redhat.com/archives/vfio-users/
  - hammerandtongs 9y ago
    Brilliant, thank you.