KVM: Document KVM_GET_MP_STATE and KVM_SET_MP_STATE

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Documentation/kvm/api.txt

@@ -848,6 +848,50 @@ function properly, this is the place to put them.
        __u8  pad[64];
 };
 
+4.37 KVM_GET_MP_STATE
+
+Capability: KVM_CAP_MP_STATE
+Architectures: x86, ia64
+Type: vcpu ioctl
+Parameters: struct kvm_mp_state (out)
+Returns: 0 on success; -1 on error
+
+struct kvm_mp_state {
+	__u32 mp_state;
+};
+
+Returns the vcpu's current "multiprocessing state" (though also valid on
+uniprocessor guests).
+
+Possible values are:
+
+ - KVM_MP_STATE_RUNNABLE:        the vcpu is currently running
+ - KVM_MP_STATE_UNINITIALIZED:   the vcpu is an application processor (AP)
+                                 which has not yet received an INIT signal
+ - KVM_MP_STATE_INIT_RECEIVED:   the vcpu has received an INIT signal, and is
+                                 now ready for a SIPI
+ - KVM_MP_STATE_HALTED:          the vcpu has executed a HLT instruction and
+                                 is waiting for an interrupt
+ - KVM_MP_STATE_SIPI_RECEIVED:   the vcpu has just received a SIPI (vector
+                                 accesible via KVM_GET_VCPU_EVENTS)
+
+This ioctl is only useful after KVM_CREATE_IRQCHIP.  Without an in-kernel
+irqchip, the multiprocessing state must be maintained by userspace.
+
+4.38 KVM_SET_MP_STATE
+
+Capability: KVM_CAP_MP_STATE
+Architectures: x86, ia64
+Type: vcpu ioctl
+Parameters: struct kvm_mp_state (in)
+Returns: 0 on success; -1 on error
+
+Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for
+arguments.
+
+This ioctl is only useful after KVM_CREATE_IRQCHIP.  Without an in-kernel
+irqchip, the multiprocessing state must be maintained by userspace.
+
 5. The kvm_run structure
 
 Application code obtains a pointer to the kvm_run structure by