[PATCH v2 6/7] KVM: arm64: vgic-its: Fix MOVALL handling of source redistributor

[Marc Zyngier]

The MOVALL command moves the pending state of all LPIs targeting a given
redistributor to another one. However, we seem to have lost the
filtering on the source RD, which means we move all LPIs to the target.

Not quite what the spec mandates.

Hack update_affinity() to take an optional source vcpu that is used as a
filter when non-NULL, restoring the filtering that was performed by
vgic_copy_lpi_list() back in the days.

Fixes: 11f4f8f3e6e06 ("KVM: arm64: vgic-its: Walk LPI xarray in vgic_its_cmd_handle_movall()")
Signed-off-by: Marc Zyngier <maz at kernel.org>
Cc: stable at vger.kernel.org
---
 arch/arm64/kvm/vgic/vgic-its.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 9e782a4fea7e5..cc02d9b62bd95 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -319,12 +319,16 @@ static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
 	return ret;
 }
 
-static int update_affinity(struct vgic_irq *irq, struct kvm_vcpu *vcpu)
+static int update_affinity(struct vgic_irq *irq,
+			   struct kvm_vcpu *from_vcpu, struct kvm_vcpu *vcpu)
 {
 	struct its_vlpi_map map;
 	int ret;
 
 	guard(raw_spinlock_irqsave)(&irq->irq_lock);
+	if (from_vcpu && irq->target_vcpu != from_vcpu)
+		return 0;
+
 	irq->target_vcpu = vcpu;
 
 	if (!irq->hw)
@@ -362,7 +366,7 @@ static void update_affinity_ite(struct kvm *kvm, struct its_ite *ite)
 		return;
 
 	vcpu = collection_to_vcpu(kvm, ite->collection);
-	update_affinity(ite->irq, vcpu);
+	update_affinity(ite->irq, NULL, vcpu);
 }
 
 /*
@@ -856,7 +860,7 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
 
 	vgic_its_invalidate_cache(its);
 
-	return update_affinity(ite->irq, vcpu);
+	return update_affinity(ite->irq, NULL, vcpu);
 }
 
 static bool __is_visible_gfn_locked(struct vgic_its *its, gpa_t gpa)
@@ -1383,7 +1387,7 @@ static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
 		if (!irq)
 			continue;
 
-		update_affinity(irq, vcpu2);
+		update_affinity(irq, vcpu1, vcpu2);
 
 		vgic_put_irq(kvm, irq);
 	}
-- 
2.47.3