KVM: arm/arm64: timer: Don't set irq as forwarded if no usable GIC

If we don't have a usable GIC, do not try to set the vcpu affinity
as this is guaranteed to fail.
Reported-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

include/kvm/arm_arch_timer.h

@@ -62,7 +62,7 @@ struct arch_timer_cpu {
 	bool			enabled;
 };
 
-int kvm_timer_hyp_init(void);
+int kvm_timer_hyp_init(bool);
 int kvm_timer_enable(struct kvm_vcpu *vcpu);
 int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu);
 void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);

virt/kvm/arm/arch_timer.c

@@ -720,7 +720,7 @@ static int kvm_timer_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
-int kvm_timer_hyp_init(void)
+int kvm_timer_hyp_init(bool has_gic)
 {
 	struct arch_timer_kvm_info *info;
 	int err;
@@ -756,11 +756,14 @@ int kvm_timer_hyp_init(void)
 		return err;
 	}
 
-	err = irq_set_vcpu_affinity(host_vtimer_irq, kvm_get_running_vcpus());
+	if (has_gic) {
+		err = irq_set_vcpu_affinity(host_vtimer_irq,
+					    kvm_get_running_vcpus());
 		if (err) {
 			kvm_err("kvm_arch_timer: error setting vcpu affinity\n");
 			goto out_free_irq;
 		}
+	}
 
 	kvm_info("virtual timer IRQ%d\n", host_vtimer_irq);
 

virt/kvm/arm/arm.c

@@ -1326,7 +1326,7 @@ static int init_subsystems(void)
 	/*
 	 * Init HYP architected timer support
 	 */
-	err = kvm_timer_hyp_init();
+	err = kvm_timer_hyp_init(vgic_present);
 	if (err)
 		goto out;