[RFC PATCH v2 01/18] vdpa: Add x-svq to NetdevVhostVDPAOptions

["Eugenio Pérez" <eperezma@redhat.com>]

Finally offering the possibility to enable SVQ from the command line.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 qapi/net.json    |  9 ++++++++-
 net/vhost-vdpa.c | 48 ++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/qapi/net.json b/qapi/net.json
index 7fab2e7cd8..6a5460ce56 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -445,12 +445,19 @@
 # @queues: number of queues to be created for multiqueue vhost-vdpa
 #          (default: 1)
 #
+# @x-svq: Start device with (experimental) shadow virtqueue. (Since 7.1)
+#         (default: false)
+#
+# Features:
+# @unstable: Member @x-svq is experimental.
+#
 # Since: 5.1
 ##
 { 'struct': 'NetdevVhostVDPAOptions',
   'data': {
     '*vhostdev':     'str',
-    '*queues':       'int' } }
+    '*queues':       'int',
+    '*x-svq':        {'type': 'bool', 'features' : [ 'unstable'] } } }
 
 ##
 # @NetClientDriver:
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 1e9fe47c03..def738998b 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -127,7 +127,11 @@ err_init:
 static void vhost_vdpa_cleanup(NetClientState *nc)
 {
     VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
+    struct vhost_dev *dev = s->vhost_vdpa.dev;
 
+    if (dev && dev->vq_index + dev->nvqs == dev->vq_index_end) {
+        g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete);
+    }
     if (s->vhost_net) {
         vhost_net_cleanup(s->vhost_net);
         g_free(s->vhost_net);
@@ -187,13 +191,23 @@ static NetClientInfo net_vhost_vdpa_info = {
         .check_peer_type = vhost_vdpa_check_peer_type,
 };
 
+static int vhost_vdpa_get_iova_range(int fd,
+                                     struct vhost_vdpa_iova_range *iova_range)
+{
+    int ret = ioctl(fd, VHOST_VDPA_GET_IOVA_RANGE, iova_range);
+
+    return ret < 0 ? -errno : 0;
+}
+
 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)
+                                       const char *device,
+                                       const char *name,
+                                       int vdpa_device_fd,
+                                       int queue_pair_index,
+                                       int nvqs,
+                                       bool is_datapath,
+                                       bool svq,
+                                       VhostIOVATree *iova_tree)
 {
     NetClientState *nc = NULL;
     VhostVDPAState *s;
@@ -211,6 +225,8 @@ 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_tree = iova_tree;
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
         qemu_del_net_client(nc);
@@ -266,6 +282,7 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
     g_autofree NetClientState **ncs = NULL;
     NetClientState *nc;
     int queue_pairs, i, has_cvq = 0;
+    g_autoptr(VhostIOVATree) iova_tree = NULL;
 
     assert(netdev->type == NET_CLIENT_DRIVER_VHOST_VDPA);
     opts = &netdev->u.vhost_vdpa;
@@ -285,29 +302,44 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
         qemu_close(vdpa_device_fd);
         return queue_pairs;
     }
+    if (opts->x_svq) {
+        struct vhost_vdpa_iova_range iova_range;
+
+        if (has_cvq) {
+            error_setg(errp, "vdpa svq does not work with cvq");
+            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);
+    }
 
     ncs = g_malloc0(sizeof(*ncs) * queue_pairs);
 
     for (i = 0; i < queue_pairs; i++) {
         ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
-                                     vdpa_device_fd, i, 2, true);
+                                     vdpa_device_fd, i, 2, true, opts->x_svq,
+                                     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);
+                                 vdpa_device_fd, i, 1, false, opts->x_svq,
+                                 iova_tree);
         if (!nc)
             goto err;
     }
 
+    iova_tree = NULL;
     return 0;
 
 err:
     if (i) {
         qemu_del_net_client(ncs[0]);
     }
+
+err_svq:
     qemu_close(vdpa_device_fd);
 
     return -1;
-- 
2.27.0