multiseat howto (with some multihead coverage)
==============================================
-host side
----------
+host devices
+------------
First you must compile qemu with a user interface supporting
multihead/multiseat and input event routing. Right now this
-list includes sdl2 and gtk (both 2+3):
+list includes sdl2, gtk (both 2+3) and vnc:
./configure --enable-sdl --with-sdlabi=2.0
./configure --enable-gtk
-Next put together the qemu command line:
+Next put together the qemu command line (sdk/gtk):
-qemu -enable-kvm -usb $memory $disk $whatever \
+qemu -accel kvm -usb $memory $disk $whatever \
-display [ sdl | gtk ] \
-vga std \
-device usb-tablet
-That is it for the first head, which will use the standard vga, the
+That is it for the first seat, which will use the standard vga, the
standard ps/2 keyboard (implicitly there) and the usb-tablet. Now the
-additional switches for the second head:
+additional switches for the second seat:
-device pci-bridge,addr=12.0,chassis_nr=2,id=head.2 \
-device secondary-vga,bus=head.2,addr=02.0,id=video.2 \
the window which belongs to the video.2 display adapter will be routed
to these input devices.
+Starting with qemu 2.4 and linux kernel 4.1 you can also use virtio
+for the input devices, using this ...
+
+ -device pci-bridge,addr=12.0,chassis_nr=2,id=head.2 \
+ -device secondary-vga,bus=head.2,addr=02.0,id=video.2 \
+ -device virtio-keyboard-pci,bus=head.2,addr=03.0,display=video.2 \
+ -device virtio-tablet-pci,bus=head.2,addr=03.0,display=video.2
+
+... instead of xhci and usb hid devices.
+
+host ui
+-------
+
The sdl2 ui will start up with two windows, one for each display
device. The gtk ui will start with a single window and each display
in a separate tab. You can either simply switch tabs to switch heads,
or use the "View / Detach tab" menu item to move one of the displays
to its own window so you can see both display devices side-by-side.
+For vnc some additional configuration on the command line is needed.
+We'll create two vnc server instances, and bind the second one to the
+second seat, similar to input devices:
+
+ -display vnc=:1,id=primary \
+ -display vnc=:2,id=secondary,display=video.2
+
+Connecting to vnc display :1 gives you access to the first seat, and
+likewise connecting to vnc display :2 shows the second seat.
+
Note on spice: Spice handles multihead just fine. But it can't do
multiseat. For tablet events the event source is sent to the spice
agent. But qemu can't figure it, so it can't do input routing.
Background info is here:
http://www.freedesktop.org/wiki/Software/systemd/multiseat/
+
+guest side with pci-bridge-seat
+-------------------------------
+
+Qemu version 2.4 and newer has a new pci-bridge-seat device which
+can be used instead of pci-bridge. Just swap the device name in the
+qemu command line above. The only difference between the two devices
+is the pci id. We can match the pci id instead of the device path
+with a nice generic rule now, which simplifies the guest
+configuration:
+
+ [root@fedora ~]# cat /etc/udev/rules.d/70-qemu-pci-bridge-seat.rules
+ SUBSYSTEM=="pci", ATTR{vendor}=="0x1b36", ATTR{device}=="0x000a", \
+ TAG+="seat", ENV{ID_AUTOSEAT}="1"
+
+Patch with this rule has been submitted to upstream udev/systemd, was
+accepted and should be included in the next systemd release (222).
+So, if your guest has this or a newer version, multiseat will work just
+fine without any manual guest configuration.
+
Enjoy!
--
projects / qemu.git / blobdiff