[Qemu-discuss] Weird mouse and keyboard problems in guests on an AMD host

[Dale Green]

Hello,

I use Qemu + KVM + virt-manager + libvirt on an AMD PC with Ryzen CPU
and an oldish Radeon GPU.

I tried 2 host distros: Debian Stretch and Arch, and the problems are
the same. I also tried Qemu without KVM and could reproduce the same.

The actual problems:
1. Moving the mouse is obviously a bit slower and the pointer jumps
slightly in the opposite direction. It's like facing some
resistance...
2. If I press some keyboard key and move the mouse, I completely lose
control over the pointer: It starts moving absolutely weirdly and even
randomly clicking around!

My main situation:
I have a virtual Ubuntu which I have been using for years on an Intel
host without problems (Thanks to all contributers for their great
job!!!). Not even the virtual tablet is added to the virtual machine.
The mouse is grabbed, but that's fine.
I try to use the same virtual disk on the AMD machine and face the
already mentioned issues. Adding a virtual tablet does not change
anything.
The only solution that worked so far was to install spice-vdagent in
the guest. However, I am not very comfortable with the shared
clipboard now...

I could reproduce the same issues with a live ISO (actually the
graphical Debian net installer). Here, the problem is easily solved by
adding a virtual tablet.

Additionally, I tried the live ISO on another Intel machine (again
Debian Stretch). No problems at all. I removed the virtual tablet and
the mouse is not even grabbed by the guest! Why is that working?

Note: I have some vmware stuff installed only on the Intel hosts. Can
it make any difference?

Finally the main question: Can somebody say what is wrong on my AMD
machine and if there is a universal solution for all guests possibly
without installing additional stuff in the guests?

Thanks!