[Spice-devel] RFC: spice plans for usb-redir + needed spice-server API extensions

[Alon Levy]

On Tue, Jul 19, 2011 at 05:00:54PM +0200, Hans de Goede wrote:
> Hi,
> 
> The plan in short:
> 
> 1) The client decides to redirect a certain usb device
>    (be it through user interaction, or based on admin configuration /
>     instructed by the controller)
> 
> 2) The client opens a new usbredir spice channel to the spice-server for
>    this (1 channel per device)
> 
> 3) spice server asks qemu to dynamically create a new spicevmc chardev
>    + usb-redir device couple (this is the part that needs the API extension).
> 
> 4) spice-server forwards requests from the channel to the chardev and
>    visa versa
> 
> 5) On of the first messages send by the client is a usbredir_device_connect
>    message, the usb-redir device checks info in this message (usb-id,
>    device class) against a configured filter which determines what kind of
>    devices can be redirected (if any), and may decide to destroy the usb-device
>    before it is ever attached to the guest. The server can notice this
>    by spice_server_remove_interface getting called for the chardev.
> 
> 6) on channel close the usb-redir device is destroyed, this also takes care
>    of closing the chardev (which it owns after qdev initalization has
>    completed)
> 
> Questions:
> 
> a) Good plan / bad plan ?
> 
> b) since the creation / destruction of the chardev + usb-redir device
>    couple is triggered by the spice-server I propose adding the following
>    2 new functions to SpiceCoreInterface:
> 
> void *(*create_usbredir_device)(void);
> void (*destroy_usbredir_device))(void *device);
> 

Hi (I think I replied to the moderator message instead of the real one,
but if you get a duplicate of this sorry).

How about a little broader api, like the chardev one (that isn't confined
to usb):

typedef enum {
    SPICE_DEVICE_USBREDIR=1,

    SPICE_DEVICE_COUNT
} spice_device_type;

 void *(*create_device)(spice_device_type device_type);
 void (*destroy_device)(spice_device_type device_type, void *device);

> create_usbredir_device returns either an opaque handle,
> or NULL on error; on success qemu_spice_add_interface() will
> have been called with a spicevmc chardev interface before this
> function returns
> 
> destroy_usbredir_device destroys the device in question.
> 
> Comments anyone ?
> 
> Regards,
> 
> Hans
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