virtio-iommu: Use recursive lock to avoid deadlock

When switching address space with mutex lock hold, mapping will be
replayed for assigned device. This will trigger relock deadlock.

Also release the mutex resource in unrealize routine.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20220613061010.2674054-3-zhenzhong.duan@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index ff718107ee..73d5bde9d1 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -78,7 +78,7 @@ static bool virtio_iommu_device_bypassed(IOMMUDevice *sdev)
 
     sid = virtio_iommu_get_bdf(sdev);
 
-    qemu_mutex_lock(&s->mutex);
+    qemu_rec_mutex_lock(&s->mutex);
     /* need to check bypass before system reset */
     if (!s->endpoints) {
         bypassed = s->config.bypass;
@@ -93,7 +93,7 @@ static bool virtio_iommu_device_bypassed(IOMMUDevice *sdev)
     }
 
 unlock:
-    qemu_mutex_unlock(&s->mutex);
+    qemu_rec_mutex_unlock(&s->mutex);
     return bypassed;
 }
 
@@ -745,7 +745,7 @@ static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
             tail.status = VIRTIO_IOMMU_S_DEVERR;
             goto out;
         }
-        qemu_mutex_lock(&s->mutex);
+        qemu_rec_mutex_lock(&s->mutex);
         switch (head.type) {
         case VIRTIO_IOMMU_T_ATTACH:
             tail.status = virtio_iommu_handle_attach(s, iov, iov_cnt);
@@ -774,7 +774,7 @@ static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
         default:
             tail.status = VIRTIO_IOMMU_S_UNSUPP;
         }
-        qemu_mutex_unlock(&s->mutex);
+        qemu_rec_mutex_unlock(&s->mutex);
 
 out:
         sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
@@ -862,7 +862,7 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     sid = virtio_iommu_get_bdf(sdev);
 
     trace_virtio_iommu_translate(mr->parent_obj.name, sid, addr, flag);
-    qemu_mutex_lock(&s->mutex);
+    qemu_rec_mutex_lock(&s->mutex);
 
     ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(sid));
     if (!ep) {
@@ -946,7 +946,7 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
     trace_virtio_iommu_translate_out(addr, entry.translated_addr, sid);
 
 unlock:
-    qemu_mutex_unlock(&s->mutex);
+    qemu_rec_mutex_unlock(&s->mutex);
     return entry;
 }
 
@@ -1035,7 +1035,7 @@ static void virtio_iommu_replay(IOMMUMemoryRegion *mr, IOMMUNotifier *n)
 
     sid = virtio_iommu_get_bdf(sdev);
 
-    qemu_mutex_lock(&s->mutex);
+    qemu_rec_mutex_lock(&s->mutex);
 
     if (!s->endpoints) {
         goto unlock;
@@ -1049,7 +1049,7 @@ static void virtio_iommu_replay(IOMMUMemoryRegion *mr, IOMMUNotifier *n)
     g_tree_foreach(ep->domain->mappings, virtio_iommu_remap, mr);
 
 unlock:
-    qemu_mutex_unlock(&s->mutex);
+    qemu_rec_mutex_unlock(&s->mutex);
 }
 
 static int virtio_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu_mr,
@@ -1167,7 +1167,7 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_PROBE);
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_BYPASS_CONFIG);
 
-    qemu_mutex_init(&s->mutex);
+    qemu_rec_mutex_init(&s->mutex);
 
     s->as_by_busptr = g_hash_table_new_full(NULL, NULL, NULL, g_free);
 
@@ -1195,6 +1195,8 @@ static void virtio_iommu_device_unrealize(DeviceState *dev)
         g_tree_destroy(s->endpoints);
     }
 
+    qemu_rec_mutex_destroy(&s->mutex);
+
     virtio_delete_queue(s->req_vq);
     virtio_delete_queue(s->event_vq);
     virtio_cleanup(vdev);