[RFC PATCH v5 14/23] vdpa: control virtqueue support on shadow virtqueue

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

Introduce the control virtqueue support for vDPA shadow virtqueue. This
is needed for advanced networking features like multiqueue.

To demonstrate command handling, VIRTIO_NET_F_CTRL_MACADDR and
VIRTIO_NET_CTRL_MQ are implemented. If vDPA device is started with SVQ
support and virtio-net driver changes MAC or the number of queues
virtio-net device model will be updated with the new one.

Others cvq commands could be added here straightforwardly but they have
been not tested.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 3 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 290aa01e13..a83da4616c 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -11,6 +11,7 @@
 
 #include "qemu/osdep.h"
 #include "clients.h"
+#include "hw/virtio/virtio-net.h"
 #include "net/vhost_net.h"
 #include "net/vhost-vdpa.h"
 #include "hw/virtio/vhost-vdpa.h"
@@ -69,6 +70,30 @@ const int vdpa_feature_bits[] = {
     VHOST_INVALID_FEATURE_BIT
 };
 
+/** Supported device specific feature bits with SVQ */
+static const uint64_t vdpa_svq_device_features =
+    BIT_ULL(VIRTIO_NET_F_CSUM) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_CSUM) |
+    BIT_ULL(VIRTIO_NET_F_CTRL_GUEST_OFFLOADS) |
+    BIT_ULL(VIRTIO_NET_F_MTU) |
+    BIT_ULL(VIRTIO_NET_F_MAC) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_TSO4) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_TSO6) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_ECN) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_UFO) |
+    BIT_ULL(VIRTIO_NET_F_HOST_TSO4) |
+    BIT_ULL(VIRTIO_NET_F_HOST_TSO6) |
+    BIT_ULL(VIRTIO_NET_F_HOST_ECN) |
+    BIT_ULL(VIRTIO_NET_F_HOST_UFO) |
+    BIT_ULL(VIRTIO_NET_F_MRG_RXBUF) |
+    BIT_ULL(VIRTIO_NET_F_STATUS) |
+    BIT_ULL(VIRTIO_NET_F_CTRL_VQ) |
+    BIT_ULL(VIRTIO_NET_F_MQ) |
+    BIT_ULL(VIRTIO_F_ANY_LAYOUT) |
+    BIT_ULL(VIRTIO_NET_F_CTRL_MAC_ADDR) |
+    BIT_ULL(VIRTIO_NET_F_RSC_EXT) |
+    BIT_ULL(VIRTIO_NET_F_STANDBY);
+
 VHostNetState *vhost_vdpa_get_vhost_net(NetClientState *nc)
 {
     VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
@@ -199,6 +224,46 @@ static int vhost_vdpa_get_iova_range(int fd,
     return ret < 0 ? -errno : 0;
 }
 
+static void vhost_vdpa_net_handle_ctrl(VirtIODevice *vdev,
+                                       const VirtQueueElement *elem)
+{
+    struct virtio_net_ctrl_hdr ctrl;
+    virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+    size_t s;
+    struct iovec in = {
+        .iov_base = &status,
+        .iov_len = sizeof(status),
+    };
+
+    s = iov_to_buf(elem->out_sg, elem->out_num, 0, &ctrl, sizeof(ctrl.class));
+    if (s != sizeof(ctrl.class)) {
+        return;
+    }
+
+    switch (ctrl.class) {
+    case VIRTIO_NET_CTRL_MAC_ADDR_SET:
+    case VIRTIO_NET_CTRL_MQ:
+        break;
+    default:
+        return;
+    };
+
+    s = iov_to_buf(elem->in_sg, elem->in_num, 0, &status, sizeof(status));
+    if (s != sizeof(status) || status != VIRTIO_NET_OK) {
+        return;
+    }
+
+    status = VIRTIO_NET_ERR;
+    virtio_net_handle_ctrl_iov(vdev, &in, 1, elem->out_sg, elem->out_num);
+    if (status != VIRTIO_NET_OK) {
+        error_report("Bad CVQ processing in model");
+    }
+}
+
+static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
+    .used_elem_handler = vhost_vdpa_net_handle_ctrl,
+};
+
 static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
                                        const char *device,
                                        const char *name,
@@ -226,6 +291,9 @@ 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;
+    if (!is_datapath) {
+        s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
+    }
     s->vhost_vdpa.iova_tree = iova_tree;
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
@@ -314,9 +382,15 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
     }
     if (opts->x_svq) {
         struct vhost_vdpa_iova_range iova_range;
-
-        if (has_cvq) {
-            error_setg(errp, "vdpa svq does not work with cvq");
+        uint64_t invalid_dev_features =
+            features & ~vdpa_svq_device_features &
+            /* Transport are all accepted at this point */
+            ~MAKE_64BIT_MASK(VIRTIO_TRANSPORT_F_START,
+                             VIRTIO_TRANSPORT_F_END - VIRTIO_TRANSPORT_F_START);
+
+        if (invalid_dev_features) {
+            error_setg(errp, "vdpa svq does not work with features 0x%" PRIx64,
+                       invalid_dev_features);
             goto err_svq;
         }
         vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
-- 
2.27.0