import

qemu/docs/multiseat.txt

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+
+multiseat howto (with some multihead coverage)
+==============================================
+
+host side
+---------
+
+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):
+
+  ./configure --enable-sdl --with-sdlabi=2.0
+
+or
+
+  ./configure --enable-gtk
+
+
+Next put together the qemu command line:
+
+qemu	-enable-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
+standard ps/2 keyboard (implicitly there) and the usb-tablet.  Now the
+additional switches for the second head:
+
+	-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 nec-usb-xhci,bus=head.2,addr=0f.0,id=usb.2 \
+	-device usb-kbd,bus=usb.2.0,port=1,display=video.2 \
+	-device usb-tablet,bus=usb.2.0,port=2,display=video.2
+
+This places a pci bridge in slot 12, connects a display adapter and
+xhci (usb) controller to the bridge.  Then it adds a usb keyboard and
+usb mouse, both connected to the xhci and linked to the display.
+
+The "display=video2" sets up the input routing.  Any input coming from
+the window which belongs to the video.2 display adapter will be routed
+to these input devices.
+
+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.
+
+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.
+Fixing this needs a new or extended input interface between
+libspice-server and qemu.  For keyboard events it is even worse:  The
+event source isn't included in the spice protocol, so the wire
+protocol must be extended to support this.
+
+
+guest side
+----------
+
+You need a pretty recent linux guest.  systemd with loginctl.  kernel
+3.14+ with CONFIG_DRM_BOCHS enabled.  Fedora 20 will do.  Must be
+fully updated for the new kernel though, i.e. the live iso doesn't cut
+it.
+
+Now we'll have to configure the guest.  Boot and login.  "lspci -vt"
+should list the pci bridge with the display adapter and usb controller:
+
+    [root@fedora ~]# lspci -vt
+    -[0000:00]-+-00.0  Intel Corporation 440FX - 82441FX PMC [Natoma]
+               [ ... ]
+               \-12.0-[01]--+-02.0  Device 1234:1111
+                            \-0f.0  NEC Corporation USB 3.0 Host Controller
+
+Good.  Now lets tell the system that the pci bridge and all devices
+below it belong to a separate seat by dropping a file into
+/etc/udev/rules.d:
+
+    [root@fedora ~]# cat /etc/udev/rules.d/70-qemu-autoseat.rules
+    SUBSYSTEMS=="pci", DEVPATH=="*/0000:00:12.0", TAG+="seat", ENV{ID_AUTOSEAT}="1"
+
+Reboot.  System should come up with two seats.  With loginctl you can
+check the configuration:
+
+    [root@fedora ~]# loginctl list-seats
+    SEAT
+    seat0
+    seat-pci-pci-0000_00_12_0
+
+    2 seats listed.
+
+You can use "loginctl seat-status seat-pci-pci-0000_00_12_0" to list
+the devices attached to the seat.
+
+Background info is here:
+  http://www.freedesktop.org/wiki/Software/systemd/multiseat/
+
+Enjoy!
+
+--
+Gerd Hoffmann <kraxel@redhat.com>