On Tue, Apr 18, 2017 at 10:09 AM, Graham Neville
<grahamneville gmail com> wrote:
> Has there been any feedback on this at all?
> I'm still struggling to get a Windows and Linux VM working at the same time
> with npt=1. Annoying as I'm having to reboot in to a different kernel if I
> want to use one or the other.
> Are you able to share your Kernel command line and XML for the Linux host
> On 7 Apr 2017 22:54, "Nick Sarnie" <commendsarnex gmail com> wrote:
> I can't reproduce that issue, I tested a Fedora VM with both npt 0 and
> 1, of course with the same GPU performance results as windows. I've
> mailed some AMD guys and KVM guys, and hopefully someone can at least
> figure out what is going on. Also, Alex has reproduced this himself on
> both Nvidia and AMD GPUs.
> On Fri, Apr 7, 2017 at 5:49 PM, Graham Neville <grahamneville gmail com>
>> I have similar oddities with npt with Ryzen. As you say with kvm-amd.npt=0
>> the GPU performance is so much better (In my Witcher3 tests I'm going from
>> 40fps to 75fps!). However with npt disabled the Windows10 VM slows down an
>> awful lot in general tasks.
>> I've also noticed that I can only run a Linux guest with kvm-amd.npt=0, if
>> have it set to enabled then the Linux guest fails to start. I have the
>> issue even just trying to install Linux from an ISO, it will crash at the
>> GRUB install menu.
>> Hopefully someone knows a fix for this.
>> vfio-users mailing list
>> vfio-users redhat com
Alex emailed Paolo, the KVM maintainer, some traces but he couldn't
find anything in them. Please follow the thread on the iommu mailing
list for more details. For now, I think we have to disable NPT.