1 files changed, 6 insertions, 18 deletions

diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
index 76ea1aa5e7d2..0e4cfe123b38 100644
--- a/arch/arm/kvm/vgic.c
+++ b/arch/arm/kvm/vgic.c
@@ -1016,21 +1016,6 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 
         kvm_debug("MISR = %08x\n", vgic_cpu->vgic_misr);
 
-        /*
-         * We do not need to take the distributor lock here, since the only
-         * action we perform is clearing the irq_active_bit for an EOIed
-         * level interrupt.  There is a potential race with
-         * the queuing of an interrupt in __kvm_vgic_flush_hwstate(), where we
-         * check if the interrupt is already active. Two possibilities:
-         *
-         * - The queuing is occurring on the same vcpu: cannot happen,
-         *   as we're already in the context of this vcpu, and
-         *   executing the handler
-         * - The interrupt has been migrated to another vcpu, and we
-         *   ignore this interrupt for this run. Big deal. It is still
-         *   pending though, and will get considered when this vcpu
-         *   exits.
-         */
         if (vgic_cpu->vgic_misr & GICH_MISR_EOI) {
                 /*
                  * Some level interrupts have been EOIed. Clear their
@@ -1069,9 +1054,8 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 }
 
 /*
- * Sync back the VGIC state after a guest run. We do not really touch
- * the distributor here (the irq_pending_on_cpu bit is safe to set),
- * so there is no need for taking its lock.
+ * Sync back the VGIC state after a guest run. The distributor lock is
+ * needed so we don't get preempted in the middle of the state processing.
  */
 static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 {
@@ -1117,10 +1101,14 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 
 void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 {
+        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
         if (!irqchip_in_kernel(vcpu->kvm))
                 return;
 
+        spin_lock(&dist->lock);
         __kvm_vgic_sync_hwstate(vcpu);
+        spin_unlock(&dist->lock);
 }
 
 int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)