KVM: PPC: Book3S HV: Move vcore preemption point up into kvmppc_run_vcpu

Rather than calling cond_resched() in kvmppc_run_core() before doing
the post-processing for the vcpus that we have just run (that is,
calling kvmppc_handle_exit_hv(), kvmppc_set_timer(), etc.), we now do
that post-processing before calling cond_resched(), and that post-
processing is moved out into its own function, post_guest_process().

The reschedule point is now in kvmppc_run_vcpu() and we define a new
vcore state, VCORE_PREEMPT, to indicate that that the vcore's runner
task is runnable but not running.  (Doing the reschedule with the
vcore in VCORE_INACTIVE state would be bad because there are potentially
other vcpus waiting for the runner in kvmppc_wait_for_exec() which
then wouldn't get woken up.)

Also, we make use of the handy cond_resched_lock() function, which
unlocks and relocks vc->lock for us around the reschedule.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/kvm_host.h

@@ -304,8 +304,9 @@ struct kvmppc_vcore {
 /* Values for vcore_state */
 #define VCORE_INACTIVE	0
 #define VCORE_SLEEPING	1
-#define VCORE_RUNNING	2
-#define VCORE_EXITING	3
+#define VCORE_PREEMPT	2
+#define VCORE_RUNNING	3
+#define VCORE_EXITING	4
 
 /*
  * Struct used to manage memory for a virtual processor area