KVM: arm/arm64: remove coarse grain dist locking at kvm_vgic_sync_hwstate

To prepare for irqfd addition, coarse grain locking is removed at
kvm_vgic_sync_hwstate level and finer grain locking is introduced in
vgic_process_maintenance only.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 5 insertions, 8 deletions

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 86cec7924611..897c849305db 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1081,6 +1081,7 @@ epilog:
 static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 {
         u32 status = vgic_get_interrupt_status(vcpu);
+        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
         bool level_pending = false;
 
         kvm_debug("STATUS = %08x\n", status);
@@ -1098,6 +1099,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
                         struct vgic_lr vlr = vgic_get_lr(vcpu, lr);
                         WARN_ON(vgic_irq_is_edge(vcpu, vlr.irq));
 
+                        spin_lock(&dist->lock);
                         vgic_irq_clear_queued(vcpu, vlr.irq);
                         WARN_ON(vlr.state & LR_STATE_MASK);
                         vlr.state = 0;
@@ -1125,6 +1127,8 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
                                 vgic_cpu_irq_clear(vcpu, vlr.irq);
                         }
 
+                        spin_unlock(&dist->lock);
+
                         /*
                          * Despite being EOIed, the LR may not have
                          * been marked as empty.
@@ -1139,10 +1143,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
         return level_pending;
 }
 
-/*
- * 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.
- */
+/* Sync back the VGIC state after a guest run */
 static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 {
         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
@@ -1189,14 +1190,10 @@ 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)