Himanshu Raj
2005-Dec-05 16:16 UTC
[Xen-devel] regarding devices in domU - bug or feature ....
Hi Folks, I am trying to develop device driver for a device as a module. There is a front end in domU and a back end in dom0. At the domU creation time, a write in xenstore corresponding to creation of BE device spurs my driver which creates appropriate data structures etc for BE, totally regardless to the FE driver. After domU finishes booting, I load the FE driver which talks to BE driver and yada yada. Problem comes when I unload the FE driver. It calls xenbus_unregister_driver, which ends up calling xenbus_dev_remove. This sets the xenbus state for that device to XenbusStateClosed. My back end driver then thinks that FE device has gone away and removes the BE device. Needless to say, further loads of FE driver are useless. If I remove that piece of code (which acts on XenbusStateClosed), then the BE device hangs around even after the domU has shut down. IMHO, shouldn''t there be a similar job of device *removal* done by xm shutdown as it is done by xm create? Then proper device removal will only happen when a guest shuts down, rather when its driver is unloaded. Or there is something totally wrong with the way I understand this issue. Best regards, Himanshu -- ------------------------------------------------------------------------- Himanshu Raj PhD Student, GaTech (www.cc.gatech.edu/~rhim) I prefer to receive attachments in an open, non-proprietary format. ------------------------------------------------------------------------- _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel