[Qemu-devel] [PATCH 3/6] vhost: Update rings information for IOTLB earlier

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Vhost-kernel backend need to receive IOTLB entries for rings
information early, but vhost-user need the same information
earlier, before VHOST_USER_SET_VRING_ADDR is sent.

This patch also trigger IOTLB miss for all rings informations
for robustness, even if in practice these adresses are on the
same page.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 hw/virtio/vhost.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 748e331..817f6d0 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -799,7 +799,17 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
         .log_guest_addr = vq->used_phys,
         .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0,
     };
-    int r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);
+    int r;
+
+    /* Update rings information for IOTLB to work correctly,
+     * vhost-kernel & vhost-user backends require for this.*/
+    if (vhost_dev_has_iommu(dev)) {
+        vhost_device_iotlb_miss(dev, addr.desc_user_addr, true);
+        vhost_device_iotlb_miss(dev, addr.used_user_addr, true);
+        vhost_device_iotlb_miss(dev, addr.avail_user_addr, true);
+    }
+
+    r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);
     if (r < 0) {
         VHOST_OPS_DEBUG("vhost_set_vring_addr failed");
         return -errno;
@@ -1551,13 +1561,6 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
 
     if (vhost_dev_has_iommu(hdev)) {
         hdev->vhost_ops->vhost_set_iotlb_callback(hdev, true);
-
-        /* Update used ring information for IOTLB to work correctly,
-         * 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);
-        }
     }
     return 0;
 fail_log:
-- 
2.9.3