vdpa: request iova_range only once

Currently iova range is requested once per queue pair in the case of
net. Reduce the number of ioctls asking it once at initialization and
reusing that value for each vhost_vdpa.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20221215113144.322011-7-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasonwang@redhat.com>

hw/virtio/vhost-vdpa.c

@@ -365,19 +365,6 @@ static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
     return 0;
 }
 
-static void vhost_vdpa_get_iova_range(struct vhost_vdpa *v)
-{
-    int ret = vhost_vdpa_call(v->dev, VHOST_VDPA_GET_IOVA_RANGE,
-                              &v->iova_range);
-    if (ret != 0) {
-        v->iova_range.first = 0;
-        v->iova_range.last = UINT64_MAX;
-    }
-
-    trace_vhost_vdpa_get_iova_range(v->dev, v->iova_range.first,
-                                    v->iova_range.last);
-}
-
 /*
  * The use of this function is for requests that only need to be
  * applied once. Typically such request occurs at the beginning
@@ -465,8 +452,6 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
         goto err;
     }
 
-    vhost_vdpa_get_iova_range(v);
-
     if (!vhost_vdpa_first_dev(dev)) {
         return 0;
     }

net/vhost-vdpa.c

@@ -541,14 +541,15 @@ static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
 };
 
 static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
-                                           const char *device,
-                                           const char *name,
-                                           int vdpa_device_fd,
-                                           int queue_pair_index,
-                                           int nvqs,
-                                           bool is_datapath,
-                                           bool svq,
-                                           VhostIOVATree *iova_tree)
+                                       const char *device,
+                                       const char *name,
+                                       int vdpa_device_fd,
+                                       int queue_pair_index,
+                                       int nvqs,
+                                       bool is_datapath,
+                                       bool svq,
+                                       struct vhost_vdpa_iova_range iova_range,
+                                       VhostIOVATree *iova_tree)
 {
     NetClientState *nc = NULL;
     VhostVDPAState *s;
@@ -567,6 +568,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
     s->vhost_vdpa.device_fd = vdpa_device_fd;
     s->vhost_vdpa.index = queue_pair_index;
     s->vhost_vdpa.shadow_vqs_enabled = svq;
+    s->vhost_vdpa.iova_range = iova_range;
     s->vhost_vdpa.iova_tree = iova_tree;
     if (!is_datapath) {
         s->cvq_cmd_out_buffer = qemu_memalign(qemu_real_host_page_size(),
@@ -646,6 +648,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
     int vdpa_device_fd;
     g_autofree NetClientState **ncs = NULL;
     g_autoptr(VhostIOVATree) iova_tree = NULL;
+    struct vhost_vdpa_iova_range iova_range;
     NetClientState *nc;
     int queue_pairs, r, i = 0, has_cvq = 0;
 
@@ -689,14 +692,12 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
         return queue_pairs;
     }
 
+    vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
     if (opts->x_svq) {
-        struct vhost_vdpa_iova_range iova_range;
-
         if (!vhost_vdpa_net_valid_svq_features(features, errp)) {
             goto err_svq;
         }
 
-        vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
         iova_tree = vhost_iova_tree_new(iova_range.first, iova_range.last);
     }
 
@@ -705,15 +706,15 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
     for (i = 0; i < queue_pairs; i++) {
         ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
                                      vdpa_device_fd, i, 2, true, opts->x_svq,
-                                     iova_tree);
+                                     iova_range, iova_tree);
         if (!ncs[i])
             goto err;
     }
 
     if (has_cvq) {
         nc = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
                                  vdpa_device_fd, i, 1, false,
-                                 opts->x_svq, iova_tree);
+                                 opts->x_svq, iova_range, iova_tree);
         if (!nc)
             goto err;
     }