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Diffstat (limited to 'qemu/docs/multiseat.txt')
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diff --git a/qemu/docs/multiseat.txt b/qemu/docs/multiseat.txt new file mode 100644 index 000000000..ebf244693 --- /dev/null +++ b/qemu/docs/multiseat.txt @@ -0,0 +1,145 @@ + +multiseat howto (with some multihead coverage) +============================================== + +host devices +------------ + +First you must compile qemu with a user interface supporting +multihead/multiseat and input event routing. Right now this +list includes sdl2, gtk (both 2+3) and vnc: + + ./configure --enable-sdl --with-sdlabi=2.0 + +or + + ./configure --enable-gtk + + +Next put together the qemu command line (sdk/gtk): + +qemu -enable-kvm -usb $memory $disk $whatever \ + -display [ sdl | gtk ] \ + -vga std \ + -device usb-tablet + +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 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 \ + -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. + +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, simliar 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. +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/ + + +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 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! + +-- +Gerd Hoffmann <kraxel@redhat.com> |