[PATCH v3 00/30] KVM: s390: enable zPCI for interpretive execution

[Matthew Rosato <mjrosato@xxxxxxxxxxxxx>]

Enable interpretive execution of zPCI instructions + adapter interruption
forwarding for s390x KVM vfio-pci.  This is done by introducing a series
of new vfio-pci feature ioctls that are unique vfio-pci-zdev (s390x) and
are used to negotiate the various aspects of zPCI interpretation setup.
By allowing intepretation of zPCI instructions and firmware delivery of
interrupts to guests, we can significantly reduce the frequency of guest
SIE exits for zPCI.  We then see additional gains by handling a hot-path
instruction that can still intercept to the hypervisor (RPCIT) directly
in kvm.