s390x/kvm: Put vm name, extended name and UUID into STSI322 SYSIB

s390x/kvm: Put vm name, extended name and UUID into STSI322 SYSIB

KVM prefills the SYSIB, returned by STSI 3.2.2. This patch allows
userspace to intercept execution, and fill in the values, that are
known to qemu: machine name (8 chars), extended machine name (256
chars), extended machine name encoding (equals 2 for UTF-8) and UUID.

STSI322 qemu handler also finds a highest virtualization level in
level-3 virtualization stack that doesn't support Extended Names
(Ext Name delimiter) and propagates zero Ext Name to all levels below,
because this level is not capable of managing Extended Names of lower
levels.

Signed-off-by: Ekaterina Tumanova <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Signed-off-by: Cornelia Huck <[email protected]>