On 01/18/2013 05:55 PM, Stefan Berger wrote: > On 01/18/2013 07:14 PM, Stefan Berger wrote: >> On 01/18/2013 01:18 PM, Eric Blake wrote: >>> On 01/18/2013 09:02 AM, Stefan Berger wrote: >> When libvirt forks, the child process inherits the file descriptors, >> among them those of the taps and /dev/tpm0. The subsequent execve >> keeps the file descriptor open. QEMU then reads the TPM file >> descriptor from the command line into above TPMInfo->fd. This also >> works with 'exec 100<>/dev/tpm0' via command line. >> Similar to the SELinux labeling of all the other file descriptors I >> also use the one for the TPM device for SELinux labeling. >> > I have to correct this: The libvirt patches for this use path= on the > command line and also apply the SELinux label on the path rather than > the fd. So, this patch then adds file descriptor passing support to have > equivalent functionality to other devices.
You _still_ don't need extra handling for fd passing; neither on the command line, nor in QMP. Remember, we added --add-fd to the command line, precisely so we could use: qemu -add-fd set=1,fd=100 -tpmdev passthrough,path=/dev/fdset/1 \ 100<>/dev/tpm0 See - by making fd passing universally accessible under pathname processing, we've made it easier to add new commands that don't have to special-case fd handling. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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