[PATCH 18/22] vdpa: manual forward CVQ buffers

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

Do a simple forwarding of CVQ buffers, the same work SVQ could do but
through callbacks. No functional change intended.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h |  3 ++
 hw/virtio/vhost-vdpa.c         |  3 +-
 net/vhost-vdpa.c               | 59 ++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 7214eb47dc..1111d85643 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -15,6 +15,7 @@
 #include <gmodule.h>
 
 #include "hw/virtio/vhost-iova-tree.h"
+#include "hw/virtio/vhost-shadow-virtqueue.h"
 #include "hw/virtio/virtio.h"
 #include "standard-headers/linux/vhost_types.h"
 
@@ -35,6 +36,8 @@ typedef struct vhost_vdpa {
     /* IOVA mapping used by the Shadow Virtqueue */
     VhostIOVATree *iova_tree;
     GPtrArray *shadow_vqs;
+    const VhostShadowVirtqueueOps *shadow_vq_ops;
+    void *shadow_vq_ops_opaque;
     struct vhost_dev *dev;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 7d2922ccbf..c1162daecc 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -419,7 +419,8 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
     for (unsigned n = 0; n < hdev->nvqs; ++n) {
         g_autoptr(VhostShadowVirtqueue) svq;
 
-        svq = vhost_svq_new(v->iova_tree, NULL, NULL);
+        svq = vhost_svq_new(v->iova_tree, v->shadow_vq_ops,
+                            v->shadow_vq_ops_opaque);
         if (unlikely(!svq)) {
             error_setg(errp, "Cannot create svq %u", n);
             return -1;
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index df1e69ee72..8558ad7a01 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -11,11 +11,14 @@
 
 #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"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
+#include "qemu/log.h"
+#include "qemu/memalign.h"
 #include "qemu/option.h"
 #include "qapi/error.h"
 #include <linux/vhost.h>
@@ -187,6 +190,58 @@ static NetClientInfo net_vhost_vdpa_info = {
         .check_peer_type = vhost_vdpa_check_peer_type,
 };
 
+/**
+ * Forward buffer for the moment.
+ */
+static bool vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
+                                             VirtQueueElement *guest_elem,
+                                             void *opaque)
+{
+    g_autofree VirtQueueElement *elem = guest_elem;
+    unsigned int n = elem->out_num + elem->in_num;
+    g_autofree struct iovec *iov = g_new(struct iovec, n);
+    size_t in_len;
+    virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+    int r;
+
+    memcpy(iov, elem->out_sg, elem->out_num);
+    memcpy(iov + elem->out_num, elem->in_sg, elem->in_num);
+
+    r = vhost_svq_inject(svq, iov, elem->out_num, elem->in_num, elem);
+    if (unlikely(r != 0)) {
+        goto err;
+    }
+
+    /* Now elem belongs to SVQ */
+    g_steal_pointer(&elem);
+    return true;
+
+err:
+    in_len = iov_from_buf(elem->in_sg, elem->in_num, 0, &status,
+                          sizeof(status));
+    vhost_svq_push_elem(svq, elem, in_len);
+    return true;
+}
+
+static VirtQueueElement *vhost_vdpa_net_handle_ctrl_detach(void *elem_opaque)
+{
+    return elem_opaque;
+}
+
+static void vhost_vdpa_net_handle_ctrl_used(VhostShadowVirtqueue *svq,
+                                            void *vq_elem_opaque,
+                                            uint32_t dev_written)
+{
+    g_autofree VirtQueueElement *guest_elem = vq_elem_opaque;
+    vhost_svq_push_elem(svq, guest_elem, sizeof(virtio_net_ctrl_ack));
+}
+
+static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
+    .avail_handler = vhost_vdpa_net_handle_ctrl_avail,
+    .used_handler = vhost_vdpa_net_handle_ctrl_used,
+    .detach_handler = vhost_vdpa_net_handle_ctrl_detach,
+};
+
 static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
                                            const char *device,
                                            const char *name,
@@ -211,6 +266,10 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
     s->vhost_vdpa.device_fd = vdpa_device_fd;
     s->vhost_vdpa.index = queue_pair_index;
+    if (!is_datapath) {
+        s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
+        s->vhost_vdpa.shadow_vq_ops_opaque = s;
+    }
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
         qemu_del_net_client(nc);
-- 
2.31.1