Coalesce map or unmap operations to exact one DMA
batch to reduce potential impact on performance.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
---
 net/vhost-vdpa.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index bc72345..1c1d61f 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -715,10 +715,11 @@ out:
                                                    v->shared->iova_range.last);
     }
 
+    vhost_vdpa_dma_batch_begin_once(v->shared, v->address_space_id);
     r = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer,
                                vhost_vdpa_net_cvq_cmd_page_len(), false);
     if (unlikely(r < 0)) {
-        return r;
+        goto err;
     }
 
     r = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, s->status,
@@ -727,18 +728,23 @@ out:
         vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);
     }
 
+err:
+    vhost_vdpa_dma_batch_end_once(v->shared, v->address_space_id);
     return r;
 }
 
 static void vhost_vdpa_net_cvq_stop(NetClientState *nc)
 {
     VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
+    struct vhost_vdpa *v = &s->vhost_vdpa;
 
     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
 
     if (s->vhost_vdpa.shadow_vqs_enabled) {
+        vhost_vdpa_dma_batch_begin_once(v->shared, v->address_space_id);
         vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);
         vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->status);
+        vhost_vdpa_dma_batch_end_once(v->shared, v->address_space_id);
     }
 
     vhost_vdpa_net_client_stop(nc);
-- 
1.8.3.1

On Fri, Dec 8, 2023 at 2:51 AM Si-Wei Liu <si-wei.liu@oracle.com> wrote:
>
> Coalesce map or unmap operations to exact one DMA
> batch to reduce potential impact on performance.
>
> Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks