KVM: arm64: Replace timer context vcpu pointer with timer_id

Having to follow a pointer to a vcpu is pretty dumb, when the timers
are are a fixed offset in the vcpu structure itself.

Trade the vcpu pointer for a timer_id, which can then be used to
compute the vcpu address as needed.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

arch/arm64/kvm/arch_timer.c

@@ -149,7 +149,7 @@ static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval)
 static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset)
 {
 	if (!ctxt->offset.vm_offset) {
-		WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt));
+		WARN(offset, "timer %d\n", arch_timer_ctx_index(ctxt));
 		return;
 	}
 
@@ -1064,7 +1064,7 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
 	struct arch_timer_context *ctxt = vcpu_get_timer(vcpu, timerid);
 	struct kvm *kvm = vcpu->kvm;
 
-	ctxt->vcpu = vcpu;
+	ctxt->timer_id = timerid;
 
 	if (timerid == TIMER_VTIMER)
 		ctxt->offset.vm_offset = &kvm->arch.timer_data.voffset;

include/kvm/arm_arch_timer.h

@@ -51,8 +51,6 @@ struct arch_timer_vm_data {
 };
 
 struct arch_timer_context {
-	struct kvm_vcpu			*vcpu;
-
 	/* Emulated Timer (may be unused) */
 	struct hrtimer			hrtimer;
 	u64				ns_frac;
@@ -71,6 +69,9 @@ struct arch_timer_context {
 		bool			level;
 	} irq;
 
+	/* Who am I? */
+	enum kvm_arch_timers		timer_id;
+
 	/* Duplicated state from arch_timer.c for convenience */
 	u32				host_timer_irq;
 };
@@ -127,9 +128,9 @@ void kvm_timer_init_vhe(void);
 #define vcpu_hvtimer(v)	(&(v)->arch.timer_cpu.timers[TIMER_HVTIMER])
 #define vcpu_hptimer(v)	(&(v)->arch.timer_cpu.timers[TIMER_HPTIMER])
 
-#define arch_timer_ctx_index(ctx)	((ctx) - vcpu_timer((ctx)->vcpu)->timers)
-#define timer_context_to_vcpu(ctx)	((ctx)->vcpu)
-#define timer_vm_data(ctx)		(&(ctx)->vcpu->kvm->arch.timer_data)
+#define arch_timer_ctx_index(ctx)	((ctx)->timer_id)
+#define timer_context_to_vcpu(ctx)	container_of((ctx), struct kvm_vcpu, arch.timer_cpu.timers[(ctx)->timer_id])
+#define timer_vm_data(ctx)		(&(timer_context_to_vcpu(ctx)->kvm->arch.timer_data))
 #define timer_irq(ctx)			(timer_vm_data(ctx)->ppi[arch_timer_ctx_index(ctx)])
 
 u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,