[PATCH 08/20] KVM: arm64: vgic-its: Spin off helper for finding ITS by doorbell addr

[Oliver Upton <oliver.upton@linux.dev>]

The fast path will soon need to find an ITS by doorbell address, as the
translation caches will become local to an ITS. Spin off a helper to do
just that.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/vgic/vgic-its.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 81f173694761..ea812f4137d9 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -509,6 +509,25 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
 	return 0;
 }
 
+static struct vgic_its *__vgic_doorbell_to_its(struct kvm *kvm, gpa_t db)
+{
+	struct kvm_io_device *kvm_io_dev;
+	struct vgic_io_device *iodev;
+
+	kvm_io_dev = kvm_io_bus_get_dev(kvm, KVM_MMIO_BUS, db);
+	if (!kvm_io_dev)
+		return ERR_PTR(-EINVAL);
+
+	if (kvm_io_dev->ops != &kvm_io_gic_ops)
+		return ERR_PTR(-EINVAL);
+
+	iodev = container_of(kvm_io_dev, struct vgic_io_device, dev);
+	if (iodev->iodev_type != IODEV_ITS)
+		return ERR_PTR(-EINVAL);
+
+	return iodev->its;
+}
+
 static struct vgic_irq *__vgic_its_check_cache(struct vgic_dist *dist,
 					       phys_addr_t db,
 					       u32 devid, u32 eventid)
@@ -686,8 +705,6 @@ int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
 struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi)
 {
 	u64 address;
-	struct kvm_io_device *kvm_io_dev;
-	struct vgic_io_device *iodev;
 
 	if (!vgic_has_its(kvm))
 		return ERR_PTR(-ENODEV);
@@ -697,18 +714,7 @@ struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi)
 
 	address = (u64)msi->address_hi << 32 | msi->address_lo;
 
-	kvm_io_dev = kvm_io_bus_get_dev(kvm, KVM_MMIO_BUS, address);
-	if (!kvm_io_dev)
-		return ERR_PTR(-EINVAL);
-
-	if (kvm_io_dev->ops != &kvm_io_gic_ops)
-		return ERR_PTR(-EINVAL);
-
-	iodev = container_of(kvm_io_dev, struct vgic_io_device, dev);
-	if (iodev->iodev_type != IODEV_ITS)
-		return ERR_PTR(-EINVAL);
-
-	return iodev->its;
+	return __vgic_doorbell_to_its(kvm, address);
 }
 
 /*
-- 
2.44.0.rc1.240.g4c46232300-goog