GICH_VMCR_ACK_CTL_SHIFT
vmcr |= (vmcrp->ackctl << GICH_VMCR_ACK_CTL_SHIFT) &
GICH_VMCR_ACK_CTL_SHIFT;
#define GICH_VMCR_ACK_CTL_MASK (1 << GICH_VMCR_ACK_CTL_SHIFT)