[PATCH v1] vhost: fail device start if iotlb update fails

[Prasad Pandit]

From: Prasad Pandit <pjp@fedoraproject.org>

While starting a vhost device, updating iotlb entries
via 'vhost_device_iotlb_miss' may return an error.

  qemu-kvm: vhost_device_iotlb_miss:
    700871,700871: Fail to update device iotlb

Fail device start when such an error occurs.

Signed-off-by: Prasad Pandit <pjp@fedoraproject.org>
---
 hw/virtio/vhost.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

v1:
 - Remove VHOST_OPS_DEBUG call.
 - Call vhost_set_iotlb_callback and vhost_dev_start with 'false' argument.

v0:
 - 20241105060053.61973-1-ppandit@redhat.com/">https://lore.kernel.org/qemu-devel/20241105060053.61973-1-ppandit@redhat.com/

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 76f9b2aaad..c40f48ac4d 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -2095,11 +2095,22 @@ int vhost_dev_start(struct vhost_dev *hdev, 
VirtIODevice *vdev, bool vrings)
          * vhost-kernel code requires for this.*/
         for (i = 0; i < hdev->nvqs; ++i) {
             struct vhost_virtqueue *vq = hdev->vqs + i;
-            vhost_device_iotlb_miss(hdev, vq->used_phys, true);
+            r = vhost_device_iotlb_miss(hdev, vq->used_phys, true);
+            if (r) {
+                goto fail_iotlb;
+            }
         }
     }
     vhost_start_config_intr(hdev);
     return 0;
+fail_iotlb:
+    if (vhost_dev_has_iommu(hdev) &&
+        hdev->vhost_ops->vhost_set_iotlb_callback) {
+        hdev->vhost_ops->vhost_set_iotlb_callback(hdev, false);
+    }
+    if (hdev->vhost_ops->vhost_dev_start) {
+        hdev->vhost_ops->vhost_dev_start(hdev, false);
+    }
 fail_start:
     if (vrings) {
         vhost_dev_set_vring_enable(hdev, false);
--
2.47.0