Re: [libvirt] [RFC PATCHv2 5/5] WIP: smartcard: turn on qemu support

On 01/18/2011 02:14 AM, Alon Levy wrote: Correct, and thanks for picking up my intended meaning. Yes, always listing backend=nss-emulated when it is compiled in, even when nss will fail at runtime because there was no access to hardware, is an acceptable solution, so long as qemu dies with a reasonable error message in that case (there, we can chalk it up to a configuration issue, where the admin is attempting to use a qemu feature without supplying the correct environment, and since libvirt will relay the qemu error message on to the user, that should be sufficient to point the user to how to fix things). Back to the earlier question of which backend device qemu will access in the host, it sounds like you will need an optional <source path='/path/to/device'/> in the XML to let libvirt know which device needs additional permissions added to allow qemu (shared) access to that device. It may also make sense to have an optional backend parameter, as in: -device ccid-card-emulated,backend=nss-emulated,path=/path/to/device to make qemu force NSS to use the given device, rather than probing, for the case when SELinux will cause NSS probing to fail. It would be nice to document what device(s) are probed when the forced device path is not present, to explain the difference between: <smartcard mode='host'/> and <smartcard mode='host'> <source path='/path/to/device'/> </smartcard> -- Eric Blake eblake(a)redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org