On Tue, Mar 06, 2018 at 12:34:33PM +0100, Gerd Hoffmann wrote:
> This series adds support for a vgpu display to the qemu vfio code.
Ok, for anyone who wants play with this, the requirements:
qemu
====
The repo at git://git.kraxel.org/qemu has a sirius/dmabufs-merge branch
with this series and spice patches and gtk patches merged.
The traditional work/intel-vgpu branch has been updated too (it is the
same as sirius/dmabufs-merge plus some work-in-progress patches).
host kernel
===========
You need a 4.16-rc kernel. The intel graphics driver comes with mdev
support. Needs gen5+ hardware (broadwell, skylake, kaby-lake). Not
sure about nvidia.
Pure software drivers are available from
git://git.kraxel.org/cgit/linux vfio-sample-display
There are three kernel modules in samples/vfio-mdev:
(1) mdpy.ko. Very simple display device. Fixed framebuffer and
resolution. Uses the region-based vfio display interface.
(2) mbochs.ko. Mimics qemu vga with bochs dispi vbe interface.
Doesn't emulate any legacy vga. But good enough to make the
bochs-drm.ko driver happy. Uses the dmabuf-based vfio display
interface. Zero-copy display updates.
(3) mdpy-fb.ko. Guest framebuffer driver for (1).
guest kernel
============
intel-gvt: 4.9+ I think.
nvidia: dunno.
mbochs: 3.14+ should work.
mdpy: The vfio-sample-display branch above if you want see guest
display updates. Without that you'll see a static test
pattern.
booting the guest
=================
Create mdev devices and use "-device vfio-pci,..." as usual, see
https://www.kernel.org/doc/Documentation/vfio-mediated-device.txt
For mdev devices using dmabufs you need opengl support.
So start qemu with spice or gtk ui and opengl enabled:
qemu -display gtk,gl=on
qemu -spice gl=on,$otherargs
When using a display without opengl support you can use egl-headless to
handle the opengl rendering and texture readout (which of course adds
some overhead):
qemu -display egl-headless -vga $display
qemu -display egl-headless -spice gl=off,$otherargs
enjoy,
Gerd
