[PATCH v3 1/2] vdpa: Restore packet receive filtering state relative with _F_CTRL_RX_EXTRA feature

[Hawkins Jiawei <yin31149@gmail.com>]

This patch refactors vhost_vdpa_net_load_rx() to
restore the packet receive filtering state in relation to
VIRTIO_NET_F_CTRL_RX_EXTRA feature at device's startup.

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
v3:
  - return early if mismatch the condition suggested by Eugenio
  - remove the `on` variable suggested by Eugenio

v2: https://lore.kernel.org/all/66ec4d7e3a680de645043d0331ab65940154f2b8.1688365324.git.yin31149@gmail.com/
  - avoid sending CVQ command in default state suggested by Eugenio

v1: https://lists.nongnu.org/archive/html/qemu-devel/2023-06/msg04957.html

 net/vhost-vdpa.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 0994836f8c..9a1905fddd 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -867,6 +867,94 @@ static int vhost_vdpa_net_load_rx(VhostVDPAState *s,
         }
     }
 
+    if (!virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_CTRL_RX_EXTRA)) {
+        return 0;
+    }
+
+    /*
+     * According to virtio_net_reset(), device turns all-unicast mode
+     * off by default.
+     *
+     * Therefore, QEMU should only send this CVQ command if the driver
+     * sets all-unicast mode on, different from the device's defaults.
+     *
+     * Note that the device's defaults can mismatch the driver's
+     * configuration only at live migration.
+     */
+    if (n->alluni) {
+        dev_written = vhost_vdpa_net_load_rx_mode(s,
+                                            VIRTIO_NET_CTRL_RX_ALLUNI, 1);
+        if (dev_written < 0) {
+            return dev_written;
+        }
+        if (*s->status != VIRTIO_NET_OK) {
+            return -EIO;
+        }
+    }
+
+    /*
+     * According to virtio_net_reset(), device turns non-multicast mode
+     * off by default.
+     *
+     * Therefore, QEMU should only send this CVQ command if the driver
+     * sets non-multicast mode on, different from the device's defaults.
+     *
+     * Note that the device's defaults can mismatch the driver's
+     * configuration only at live migration.
+     */
+    if (n->nomulti) {
+        dev_written = vhost_vdpa_net_load_rx_mode(s,
+                                            VIRTIO_NET_CTRL_RX_NOMULTI, 1);
+        if (dev_written < 0) {
+            return dev_written;
+        }
+        if (*s->status != VIRTIO_NET_OK) {
+            return -EIO;
+        }
+    }
+
+    /*
+     * According to virtio_net_reset(), device turns non-unicast mode
+     * off by default.
+     *
+     * Therefore, QEMU should only send this CVQ command if the driver
+     * sets non-unicast mode on, different from the device's defaults.
+     *
+     * Note that the device's defaults can mismatch the driver's
+     * configuration only at live migration.
+     */
+    if (n->nouni) {
+        dev_written = vhost_vdpa_net_load_rx_mode(s,
+                                            VIRTIO_NET_CTRL_RX_NOUNI, 1);
+        if (dev_written < 0) {
+            return dev_written;
+        }
+        if (*s->status != VIRTIO_NET_OK) {
+            return -EIO;
+        }
+    }
+
+    /*
+     * According to virtio_net_reset(), device turns non-broadcast mode
+     * off by default.
+     *
+     * Therefore, QEMU should only send this CVQ command if the driver
+     * sets non-broadcast mode on, different from the device's defaults.
+     *
+     * Note that the device's defaults can mismatch the driver's
+     * configuration only at live migration.
+     */
+    if (n->nobcast) {
+        dev_written = vhost_vdpa_net_load_rx_mode(s,
+                                            VIRTIO_NET_CTRL_RX_NOBCAST, 1);
+        if (dev_written < 0) {
+            return dev_written;
+        }
+        if (*s->status != VIRTIO_NET_OK) {
+            return -EIO;
+        }
+    }
+
     return 0;
 }
 
-- 
2.25.1