[Qemu-devel] [PULL v3 26/28] vhost: drop legacy vring layout bits

["Michael S. Tsirkin" <mst@redhat.com>]

From: Greg Kurz <groug@kaod.org>

The legacy vring layout is not used anymore as we use the separate
mappings even for legacy devices.
This patch simply removes it.

This also fixes a bug with virtio 1 devices when the vring descriptor table
is mapped at a higher address than the used vring because the following
function may return an insanely great value:

hwaddr virtio_queue_get_ring_size(VirtIODevice *vdev, int n)
{
    return vdev->vq[n].vring.used - vdev->vq[n].vring.desc +
           virtio_queue_get_used_size(vdev, n);
}

and the mapping fails.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/virtio/vhost.h |  3 ---
 hw/virtio/vhost.c         | 13 -------------
 2 files changed, 16 deletions(-)

diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 56b567f..1fe5aad 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -20,9 +20,6 @@ struct vhost_virtqueue {
     unsigned avail_size;
     unsigned long long used_phys;
     unsigned used_size;
-    void *ring;
-    unsigned long long ring_phys;
-    unsigned ring_size;
     EventNotifier masked_notifier;
 };
 
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index d88d34a..30aee88 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -923,14 +923,6 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
         goto fail_alloc_used;
     }
 
-    vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx);
-    vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx);
-    vq->ring = cpu_physical_memory_map(a, &l, 1);
-    if (!vq->ring || l != s) {
-        r = -ENOMEM;
-        goto fail_alloc_ring;
-    }
-
     r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled);
     if (r < 0) {
         r = -errno;
@@ -971,9 +963,6 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
 fail_vector:
 fail_kick:
 fail_alloc:
-    cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
-                              0, 0);
-fail_alloc_ring:
     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
                               0, 0);
 fail_alloc_used:
@@ -1014,8 +1003,6 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
                                                 vhost_vq_index);
     }
 
-    cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
-                              0, virtio_queue_get_ring_size(vdev, idx));
     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
                               1, virtio_queue_get_used_size(vdev, idx));
     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
-- 
MST