[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V9 0/7] xen pvusb toolstack work
According to current active discussion: libxl: Introduce a template for devices with a controller https://www.mail-archive.com/xen-devel@xxxxxxxxxxxxx/msg46720.html Will update naming and RESEND. - Chunyan >>> On 11/24/2015 at 04:35 PM, in message <1448354134-21644-1-git-send-email-cyliu@xxxxxxxx>, Chunyan Liu <cyliu@xxxxxxxx> wrote: > This patch series is to add pvusb toolstack work, supporting hot add|remove > USB device to|from guest and specify USB device in domain configuration > file. > > Changes to V8: > * lots of changes in libxl pvusb API (patch 3/7) > * update 2/7 to write separate read_sysfs_file function > * address all other comments > > V8: > http://lists.xen.org/archives/html/xen-devel/2015-10/msg02178.html > > V7: > http://lists.xen.org/archives/html/xen-devel/2015-09/msg03115.html > > V6: > http://lists.xen.org/archives/html/xen-devel/2015-08/msg00750.html > > V5: > http://lists.xen.org/archives/html/xen-devel/2015-06/msg04052.html > > V4: > http://lists.xenproject.org/archives/html/xen-devel/2015-06/msg01327.html > > Related Discussion Threads: > http://www.redhat.com/archives/libvir-list/2014-June/msg00038.html > http://lists.xen.org/archives/html/xen-devel/2014-06/msg00086.html > > <<< pvusb work introduction >>> > > 1. Overview > > There are two general methods for passing through individual host > devices to a guest. The first is via an emulated USB device > controller; the second is PVUSB. > > Additionally, there are two ways to add USB devices to a guest: via > the config file at domain creation time, and via hot-plug while the VM > is running. > > * Emulated USB > > In emulated USB, the device model (qemu) presents an emulated USB > controller to the guest. The device model process then grabs control > of the device from domain 0 and and passes the USB commands between > the guest OS and the host USB device. > > This method is only available to HVM domains, and is not available for > domains running with device model stubdomains. > > * PVUSB > > PVUSB uses a paravirtialized front-end/back-end interface, similar to > the traditional Xen PV network and disk protocols. In order to use > PVUSB, you need usbfront in your guest OS, and usbback in dom0 (or > your USB driver domain). > > 2. Specifying a host USB device > > QEMU qmp commands allows USB devices to be specified either by their > bus address (in the form bus.device) or their device tag (in the form > vendorid:deviceid). > > Each way of specifying has its advantages: > > Specifying by device tag will always get the same device, > regardless of where the device ends up in the USB bus topology. > However, if there are two identical devices, it will not allow you to > specify which one. > > Specifying by bus address will always allow you to choose a > specific device, even if you have duplicates. However, the bus address > may change depending on which port you plugged the device into, and > possibly also after a reboot. > > To avoid duplication of vendorid:deviceid, we'll use bus address to > specify host USB device in xl toolstack. > > You can use lsusb to list the USB devices on the system: > > Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 > Hub > Bus 003 Device 002: ID f617:0905 > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 001 Device 004: ID 0424:2640 Standard Microsystems Corp. USB 2.0 > Hub > Bus 001 Device 005: ID 0424:4060 Standard Microsystems Corp. Ultra > Fast Media Reader > Bus 001 Device 006: ID 046d:c016 Logitech, Inc. Optical Wheel Mouse > > To pass through the Logitec mouse, for instance, you could specify > 1.6 (remove leading zeroes). > > Note: USB hubs can not be assigned to guest. > > 3. PVUSB toolstack > > * Specify USB device in xl config file > > You can just specify usb devices, like: > usbdev=['1.6'] > > Then it will create a USB controller automatically and attach the USB > device to the first available USB controller:port. > > or, you can explicitly specify usb controllers and usb devices, like: > usbctrl=['verison=1, ports=4', 'version=2, ports=8', ] > usbdev=['1.6, controller=0, port=1'] > > Then it will create two USB controllers as you specified. > And if controller and port are specified in usb config, then it will > attach the USB device to that controller:port. About the controller > and port value: > Each USB controller has a index (or called devid) based on 0. The 1st > controller has index 0, the 2nd controller has index 1, ... > Under controller, each port has a port number based on 1. In above > configuration, the 1st controller will have port 1,2,3,4. > > * Hot-Plug USB device > > To attach a USB device, you should first create a USB controller. > e.g. > xl usb-ctrl-attach domain [version=1|2] [ports=value] > By default, it will create a USB2.0 controller with 8 ports. > > Then you could attach a USB device. > e.g. > xl usb-attach domain 1.6 [controller=index port=number] > By default, it will find the 1st available controller:port to attach > the USB device. > > You could view USB device status of the domain by usb-list. > e.g. > xl usb-list domain > It will list USB controllers and USB devices under each controller. > > You could detach a USB device with usb-detach command. > e.g. > xl usb-detach domain 1.6 > > You can also remove the whole USB controller by usb-ctrl-detach > command. > e.g. > xl usb-ctrl-detach domain 0 > It will remove the USB controller with index 0 and all USB devices > under it. > > 4. PVUSB Libxl implementation > > * usb-ctrl-attach > To create a usb controller, we need: > 1) generate usb controler related information > 2) write usb controller frontend/backend info to xenstore > PVUSB frontend and backend driver will probe xenstore paths and build > connection between frontend and backend. > > * usb-ctrl-detach > To remove a usb controller, we need: > 1) check if the usb controller exists or not > 2) remove all usb devices under controller > 3) remove usb controller info from xenstore > > * usb-attach > To attach a usb device, we need: > 1) check if the usb device type is assignable > 2) check if the usb device is already assigned to a domain > 3) add 'busid' of the usb device to xenstore contoller/port/. > PVUSB driver watches the xenstore changes and detects that, > and needs to use 'busid' to do following work. > 4) unbind usb device from original driver and bind to usbback. > If usb device has many interfaces, then: > - unbind each interface from its original driver and bind to usbback. > - store the original driver to xenstore for later rebinding when > detaching the device. > > * usb-detach > To detach a usb device, we need: > 1) check if the usb device is assigned to the domain > 2) remove the usb device from xenstore controller/port. > 3) unbind usb device from usbback and rebind to its original driver. > If usb device has many interfaces, do it to each interface. > > * usb-list > List all USB controllers and USB devices under each controller. > > 5. PVUSB xenstore information > > PVUSB xenstore information includes three parts: frontend, backend > and /libxl part. > > A USB controller is corresponding to a "vusb" device in xenstore. > Adding a USB controller will add a new "vusb" device, removing a > USB controller will delete the related "vusb" device. > > Following is an example xenstore values of a USB controller. > Backend: > backend = "" > vusb = "" > 1 = "" > 0 = "" > frontend = "/local/domain/1/device/vusb/0" > frontend-id = "1" > online = "1" > state = "4" > type = "pv" > usb-ver = "1" > num-ports = "4" > port = "" > 1 = "" > 2 = "" > 3 = "" > 4 = "" > > Frontend: > device = "" > vusb = "" > 0 = "" > backend = "/local/domain/0/backend/vusb/1/0" > backend-id = "0" > state = "4" > urb-ring-ref = "348" > conn-ring-ref = "346" > event-channel = "20" > > Adding a USB device won't create a new "vusb" device, but only write > the USB device busid to one port of USB controller. > For example, attaching a USB device (busid is 2-1.6) to above USB > controller port 1, it only need write 2-1.6 to port 1 of this USB > controller: > Backend: > backend = "" > vusb = "" > 1 = "" > 0 = "" > frontend = "/local/domain/1/device/vusb/0" > frontend-id = "1" > online = "1" > state = "4" > type = "pv" > usb-ver = "1" > num-ports = "4" > port = "" > 1 = "2-1.6" > 2 = "" > 3 = "" > 4 = "" > Frontend doesn't change. > > Since assign a host USB device to guest, we'll unbind USB interfaces > from their original drivers and bind them to usbback. After detaching > this USB device from guest, one would hope the USB interfaces could > be rebind to their original drivers, so there should some place to > get the original driver info. To support that, when attaching a USB > device to guest, we'll save the original driver info in xenstore too, > the place is /libxl/usbback, for example: > libxl = "" > 1 = "" > dm-version = "qemu_xen" > usbback = "" > 3-11 = "" > 3-11@1_0 = "" > driver_path = "/sys/bus/usb/drivers/btusb" > > In this example, USB device (busid is 3-11, /sys/bus/usb/devices/3-11). > It has interface 3-11:1.0, whose original dirver is btusb. > Since xenstore doesn't allow ':' and '.' in a key, so we encode the > interface by changing ':' to '@' and changing '.' to '_'. > > When detaching the USB device from guest, we can rebind 3-11:1.0 to > btusb driver. > > Chunyan Liu (7): > libxl: export some functions for pvusb use > libxl_utils: add internal function to read sysfs file contents > libxl: add pvusb API > libxl: add libxl_device_usb_assignable_list API > xl: add pvusb commands > xl: add usb-assignable-list command > domcreate: support pvusb in configuration file > > docs/man/xl.cfg.pod.5 | 84 ++ > docs/man/xl.pod.1 | 41 + > tools/libxl/Makefile | 2 +- > tools/libxl/libxl.c | 55 +- > tools/libxl/libxl.h | 77 ++ > tools/libxl/libxl_create.c | 73 +- > tools/libxl/libxl_device.c | 9 +- > tools/libxl/libxl_internal.h | 34 + > tools/libxl/libxl_osdeps.h | 13 + > tools/libxl/libxl_pvusb.c | 1584 > ++++++++++++++++++++++++++++++++++ > tools/libxl/libxl_types.idl | 46 + > tools/libxl/libxl_types_internal.idl | 1 + > tools/libxl/libxl_utils.c | 95 ++ > tools/libxl/libxl_utils.h | 5 + > tools/libxl/xl.h | 6 + > tools/libxl/xl_cmdimpl.c | 322 ++++++- > tools/libxl/xl_cmdtable.c | 29 + > 17 files changed, 2466 insertions(+), 10 deletions(-) > create mode 100644 tools/libxl/libxl_pvusb.c _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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