[libvirt] virtual smartcard support for GPG backend?

[roky at openmailbox.org]

Hi. I am trying to get a virtual smartcard attached to a vm but I want 
it to use GPG instead of NSS. RedHat focuses on NSS becuase of PKCS#11 
requirements and FIPS approval, but for most of the community its GPG 
that matters for smartcards.

Is is possible to use GPG on the host instead of NSS with virtual 
smartcards? Please document how or add support for it.

Is using a virtual smartcard make the host less secure from a rogue vm? 
If there are bugs in GPG/NSS backend on the host can they be abused by 
untrusted code in the vm?