KVM: arm/arm64: Move timer/vgic flush/sync under disabled irq

As we are about to play tricks with the timer to be more lazy in saving
and restoring state, we need to move the timer sync and flush functions
under a disabled irq section and since we have to flush the vgic state
after the timer and PMU state, we do the whole flush/sync sequence with
disabled irqs.

The only downside is a slightly longer delay before being able to
process hardware interrupts and run softirqs.
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>

virt/kvm/arm/arm.c

@@ -654,11 +654,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 		kvm_pmu_flush_hwstate(vcpu);
 
+		local_irq_disable();
+
 		kvm_timer_flush_hwstate(vcpu);
 		kvm_vgic_flush_hwstate(vcpu);
 
-		local_irq_disable();
-
 		/*
 		 * If we have a singal pending, or need to notify a userspace
 		 * irqchip about timer or PMU level changes, then we exit (and
@@ -683,10 +683,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) ||
 		    kvm_request_pending(vcpu)) {
 			vcpu->mode = OUTSIDE_GUEST_MODE;
-			local_irq_enable();
 			kvm_pmu_sync_hwstate(vcpu);
 			kvm_timer_sync_hwstate(vcpu);
 			kvm_vgic_sync_hwstate(vcpu);
+			local_irq_enable();
 			preempt_enable();
 			continue;
 		}
@@ -709,6 +709,16 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 		kvm_arm_clear_debug(vcpu);
 
+		/*
+		 * We must sync the PMU and timer state before the vgic state so
+		 * that the vgic can properly sample the updated state of the
+		 * interrupt line.
+		 */
+		kvm_pmu_sync_hwstate(vcpu);
+		kvm_timer_sync_hwstate(vcpu);
+
+		kvm_vgic_sync_hwstate(vcpu);
+
 		/*
 		 * We may have taken a host interrupt in HYP mode (ie
 		 * while executing the guest). This interrupt is still
@@ -732,16 +742,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		guest_exit();
 		trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
 
-		/*
-		 * We must sync the PMU and timer state before the vgic state so
-		 * that the vgic can properly sample the updated state of the
-		 * interrupt line.
-		 */
-		kvm_pmu_sync_hwstate(vcpu);
-		kvm_timer_sync_hwstate(vcpu);
-
-		kvm_vgic_sync_hwstate(vcpu);
-
 		preempt_enable();
 
 		ret = handle_exit(vcpu, run, ret);