[PATCH 5/8] KVM: arm/arm64: vgic-its: Invalidate MSI-LPI translation cache on specific commands

[Marc Zyngier <marc.zyngier@arm.com>]

The LPI translation cache needs to be discarded when an ITS command
may affect the translation of an LPI (DISCARD and MAPD with V=0) or
the routing of an LPI to a redistributor with disabled LPIs (MOVI,
MOVALL).

We decide to perform a full invalidation of the cache, irrespective
of the LPI that is affected. Commands are supposed to be rare enough
that it doesn't matter.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 virt/kvm/arm/vgic/vgic-its.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index f637edd77e1f..62917aa15493 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -577,6 +577,29 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
 	raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
 }
 
+static void vgic_its_invalidate_cache(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct vgic_translation_cache_entry *cte;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
+
+	list_for_each_entry(cte, &dist->lpi_translation_cache, entry) {
+		/*
+		 * If we hit a NULL entry, there is nothing after this
+		 * point.
+		 */
+		if (!cte->irq)
+			break;
+
+		__vgic_put_lpi_locked(kvm, cte->irq);
+		cte->irq = NULL;
+	}
+
+	raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+}
+
 int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
 			 u32 devid, u32 eventid, struct vgic_irq **irq)
 {
@@ -743,6 +766,8 @@ static int vgic_its_cmd_handle_discard(struct kvm *kvm, struct vgic_its *its,
 		 * don't bother here since we clear the ITTE anyway and the
 		 * pending state is a property of the ITTE struct.
 		 */
+		vgic_its_invalidate_cache(kvm);
+
 		its_free_ite(kvm, ite);
 		return 0;
 	}
@@ -778,6 +803,8 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
 	ite->collection = collection;
 	vcpu = kvm_get_vcpu(kvm, collection->target_addr);
 
+	vgic_its_invalidate_cache(kvm);
+
 	return update_affinity(ite->irq, vcpu);
 }
 
@@ -1007,6 +1034,8 @@ static void vgic_its_free_device(struct kvm *kvm, struct its_device *device)
 	list_for_each_entry_safe(ite, temp, &device->itt_head, ite_list)
 		its_free_ite(kvm, ite);
 
+	vgic_its_invalidate_cache(kvm);
+
 	list_del(&device->dev_list);
 	kfree(device);
 }
@@ -1260,6 +1289,8 @@ static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
 		vgic_put_irq(kvm, irq);
 	}
 
+	vgic_its_invalidate_cache(kvm);
+
 	kfree(intids);
 	return 0;
 }
-- 
2.20.1

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm