From 20e7412bfd63c68f1798fbdb799aedb7e05fee88 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
Date: Thu, 15 Dec 2022 12:31:34 +0100
Subject: [PATCH] vhost: set SVQ device call handler at SVQ start
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By the end of this series CVQ is shadowed as long as the features
support it.

Since we don't know at the beginning of qemu running if this is
supported, move the event notifier handler setting to the start of the
SVQ, instead of the start of qemu run. This will avoid to create them if
the device does not support SVQ.

Signed-off-by: Eugenio PĂ©rez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221215113144.322011-3-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 5bd14cad96..264ddc166d 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -648,6 +648,7 @@ void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
 {
     size_t desc_size, driver_size, device_size;
 
+    event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
     svq->next_guest_avail_elem = NULL;
     svq->shadow_avail_idx = 0;
     svq->shadow_used_idx = 0;
@@ -704,6 +705,7 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
     g_free(svq->desc_state);
     qemu_vfree(svq->vring.desc);
     qemu_vfree(svq->vring.used);
+    event_notifier_set_handler(&svq->hdev_call, NULL);
 }
 
 /**
@@ -740,7 +742,6 @@ VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree,
     }
 
     event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
-    event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
     svq->iova_tree = iova_tree;
     svq->ops = ops;
     svq->ops_opaque = ops_opaque;
@@ -763,7 +764,6 @@ void vhost_svq_free(gpointer pvq)
     VhostShadowVirtqueue *vq = pvq;
     vhost_svq_stop(vq);
     event_notifier_cleanup(&vq->hdev_kick);
-    event_notifier_set_handler(&vq->hdev_call, NULL);
     event_notifier_cleanup(&vq->hdev_call);
     g_free(vq);
 }