On 27/09/16 10:51, Gerd Hoffmann wrote: > On Mo, 2016-09-26 at 14:43 +0200, Juergen Gross wrote: >> Trying to use pvUSB in a Xen guest with a qemu emulated USB controller >> will crash qemu as it tries to attach a pvUSB device to the emulated >> controller. > > Hmm. --verbose please. > > While this clearly doesn't do what you intended I think it should not > have crashed qemu. pvUSB devices should work on emulated controller > (and emulated devices should work on the pvUSB controller). If they > don't you probably taking shortcuts somewhere which work only for the > pvUSB device on pvUSB controller case.
Of course a pvUSB device connected by the pvUSB controller is expecting to be on that controller when doing I/Os. I believe this was the problem here: The device was attached to an emulated USB controller and the pvUSB controller started an I/O which confused the emulated one. > Please check. There is something wrong, sure. A pvUSB device ending on the wrong controller should never receive I/Os from the pvUSB controller. I'll check that. But this problem is independent from the one solved by these patches: I have to make sure the device is connected to the pvUSB controller or otherwise the guest won't be able to access it the way it was meant to. Juergen
