KVM: arm64: Wrapper for getting pmu_events

Eases migrating away from using hyp data and simplifies the code.

No functional change intended.

Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220510095710.148178-2-tabba@google.com

Author: Fuad Tabba

arch/arm64/kvm/pmu.c

@@ -25,35 +25,45 @@ static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)
 	return (attr->exclude_host != attr->exclude_guest);
 }
 
+static struct kvm_pmu_events *kvm_get_pmu_events(void)
+{
+	struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+
+	if (!ctx)
+		return NULL;
+
+	return &ctx->pmu_events;
+}
+
 /*
  * Add events to track that we may want to switch at guest entry/exit
  * time.
  */
 void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
 {
-	struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+	struct kvm_pmu_events *pmu = kvm_get_pmu_events();
 
-	if (!kvm_arm_support_pmu_v3() || !ctx || !kvm_pmu_switch_needed(attr))
+	if (!kvm_arm_support_pmu_v3() || !pmu || !kvm_pmu_switch_needed(attr))
 		return;
 
 	if (!attr->exclude_host)
-		ctx->pmu_events.events_host |= set;
+		pmu->events_host |= set;
 	if (!attr->exclude_guest)
-		ctx->pmu_events.events_guest |= set;
+		pmu->events_guest |= set;
 }
 
 /*
  * Stop tracking events
  */
 void kvm_clr_pmu_events(u32 clr)
 {
-	struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+	struct kvm_pmu_events *pmu = kvm_get_pmu_events();
 
-	if (!kvm_arm_support_pmu_v3() || !ctx)
+	if (!kvm_arm_support_pmu_v3() || !pmu)
 		return;
 
-	ctx->pmu_events.events_host &= ~clr;
-	ctx->pmu_events.events_guest &= ~clr;
+	pmu->events_host &= ~clr;
+	pmu->events_guest &= ~clr;
 }
 
 #define PMEVTYPER_READ_CASE(idx)				\
@@ -169,16 +179,16 @@ static void kvm_vcpu_pmu_disable_el0(unsigned long events)
  */
 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
 {
-	struct kvm_host_data *host;
+	struct kvm_pmu_events *pmu;
 	u32 events_guest, events_host;
 
 	if (!kvm_arm_support_pmu_v3() || !has_vhe())
 		return;
 
 	preempt_disable();
-	host = this_cpu_ptr_hyp_sym(kvm_host_data);
-	events_guest = host->pmu_events.events_guest;
-	events_host = host->pmu_events.events_host;
+	pmu = kvm_get_pmu_events();
+	events_guest = pmu->events_guest;
+	events_host = pmu->events_host;
 
 	kvm_vcpu_pmu_enable_el0(events_guest);
 	kvm_vcpu_pmu_disable_el0(events_host);
@@ -190,15 +200,15 @@ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
  */
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu)
 {
-	struct kvm_host_data *host;
+	struct kvm_pmu_events *pmu;
 	u32 events_guest, events_host;
 
 	if (!kvm_arm_support_pmu_v3() || !has_vhe())
 		return;
 
-	host = this_cpu_ptr_hyp_sym(kvm_host_data);
-	events_guest = host->pmu_events.events_guest;
-	events_host = host->pmu_events.events_host;
+	pmu = kvm_get_pmu_events();
+	events_guest = pmu->events_guest;
+	events_host = pmu->events_host;
 
 	kvm_vcpu_pmu_enable_el0(events_host);
 	kvm_vcpu_pmu_disable_el0(events_guest);