KVM: arm/arm64: Rework the timer code to use a timer_map

We are currently emulating two timers in two different ways.  When we
add support for nested virtualization in the future, we are going to be
emulating either two timers in two diffferent ways, or four timers in a
single way.

We need a unified data structure to keep track of how we map virtual
state to physical state and we need to cleanup some of the timer code to
operate more independently on a struct arch_timer_context instead of
trying to consider the global state of the VCPU and recomputing all
state.

Co-written with Marc Zyngier <marc.zyngier@arm.com>

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>

include/kvm/arm_arch_timer.h

@@ -51,11 +51,24 @@ struct arch_timer_context {
 	/* Emulated Timer (may be unused) */
 	struct hrtimer			hrtimer;
 
+	/*
+	 * We have multiple paths which can save/restore the timer state onto
+	 * the hardware, so we need some way of keeping track of where the
+	 * latest state is.
+	 */
+	bool				loaded;
+
 	/* Duplicated state from arch_timer.c for convenience */
 	u32				host_timer_irq;
 	u32				host_timer_irq_flags;
 };
 
+struct timer_map {
+	struct arch_timer_context *direct_vtimer;
+	struct arch_timer_context *direct_ptimer;
+	struct arch_timer_context *emul_ptimer;
+};
+
 struct arch_timer_cpu {
 	struct arch_timer_context timers[NR_KVM_TIMERS];
 
@@ -64,16 +77,6 @@ struct arch_timer_cpu {
 
 	/* Is the timer enabled */
 	bool			enabled;
-
-	/*
-	 * We have multiple paths which can save/restore the timer state
-	 * onto the hardware, so we need some way of keeping track of
-	 * where the latest state is.
-	 *
-	 * loaded == true:  State is loaded on the hardware registers.
-	 * loaded == false: State is stored in memory.
-	 */
-	bool			loaded;
 };
 
 int kvm_timer_hyp_init(bool);