[PATCH 4/5] vfio-pci: Generalize setup of simple eventfds

[Alex Williamson <alex.williamson@redhat.com>]

We want another single vector IRQ index to support signaling of
the device request to userspace.  Generalize the error reporting
IRQ index to avoid code duplication.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

 drivers/vfio/pci/vfio_pci_intrs.c |   44 ++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index e8d695b..b134bef 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -763,46 +763,60 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_device *vdev,
 	return 0;
 }
 
-static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
-				    unsigned index, unsigned start,
-				    unsigned count, uint32_t flags, void *data)
+static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
+					   uint32_t flags, void *data)
 {
 	int32_t fd = *(int32_t *)data;
 
-	if ((index != VFIO_PCI_ERR_IRQ_INDEX) ||
-	    !(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
+	if (!(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
 		return -EINVAL;
 
 	/* DATA_NONE/DATA_BOOL enables loopback testing */
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
-		if (vdev->err_trigger)
-			eventfd_signal(vdev->err_trigger, 1);
+		if (*ctx)
+			eventfd_signal(*ctx, 1);
 		return 0;
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t trigger = *(uint8_t *)data;
-		if (trigger && vdev->err_trigger)
-			eventfd_signal(vdev->err_trigger, 1);
+		if (trigger && *ctx)
+			eventfd_signal(*ctx, 1);
 		return 0;
 	}
 
 	/* Handle SET_DATA_EVENTFD */
 	if (fd == -1) {
-		if (vdev->err_trigger)
-			eventfd_ctx_put(vdev->err_trigger);
-		vdev->err_trigger = NULL;
+		if (*ctx)
+			eventfd_ctx_put(*ctx);
+		*ctx = NULL;
 		return 0;
 	} else if (fd >= 0) {
 		struct eventfd_ctx *efdctx;
 		efdctx = eventfd_ctx_fdget(fd);
 		if (IS_ERR(efdctx))
 			return PTR_ERR(efdctx);
-		if (vdev->err_trigger)
-			eventfd_ctx_put(vdev->err_trigger);
-		vdev->err_trigger = efdctx;
+		if (*ctx)
+			eventfd_ctx_put(*ctx);
+		*ctx = efdctx;
 		return 0;
 	} else
 		return -EINVAL;
 }
+
+static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
+				    unsigned index, unsigned start,
+				    unsigned count, uint32_t flags, void *data)
+{
+	if (index != VFIO_PCI_ERR_IRQ_INDEX)
+		return -EINVAL;
+
+	/*
+	 * We should sanitize start & count, but that wasn't caught
+	 * originally, so this IRQ index must forever ignore them :-(
+	 */
+
+	return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger, flags, data);
+}
+
 int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
 			    unsigned index, unsigned start, unsigned count,
 			    void *data)