From 88dfb4236c735c608f8ca91cfbfb5ac424d654aa Mon Sep 17 00:00:00 2001
From: Jinhua Cao <caojinhua1@huawei.com>
Date: Thu, 10 Feb 2022 17:28:49 +0800
Subject: [PATCH] virtio-net: update the default and max of rx/tx_queue_size

Set the max of tx_queue_size to 4096 even if the backends
are not vhost-user.

Set the default of rx/tx_queue_size to 2048 if the backends
are vhost-user, otherwise to 4096.

Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>
---
 hw/net/virtio-net.c | 41 +++++++++++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 009dc9f3d1..e887589a30 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -51,12 +51,11 @@
 #define MAX_VLAN    (1 << 12)   /* Per 802.1Q definition */
 
 /* previously fixed value */
-#define VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE 256
-#define VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE 256
+#define VIRTIO_NET_VHOST_USER_DEFAULT_SIZE 2048
 
 /* for now, only allow larger queue_pairs; with virtio-1, guest can downsize */
-#define VIRTIO_NET_RX_QUEUE_MIN_SIZE VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE
-#define VIRTIO_NET_TX_QUEUE_MIN_SIZE VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE
+#define VIRTIO_NET_RX_QUEUE_MIN_SIZE 256
+#define VIRTIO_NET_TX_QUEUE_MIN_SIZE 256
 
 #define VIRTIO_NET_IP4_ADDR_SIZE   8        /* ipv4 saddr + daddr */
 
@@ -622,6 +621,28 @@ static void virtio_net_set_mrg_rx_bufs(VirtIONet *n, int mergeable_rx_bufs,
     }
 }
 
+static void virtio_net_set_default_queue_size(VirtIONet *n)
+{
+    NetClientState *peer = n->nic_conf.peers.ncs[0];
+
+    /* Default value is 0 if not set */
+    if (n->net_conf.rx_queue_size == 0) {
+        if (peer && peer->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
+            n->net_conf.rx_queue_size = VIRTIO_NET_VHOST_USER_DEFAULT_SIZE;
+        } else {
+            n->net_conf.rx_queue_size = VIRTIO_NET_VQ_MAX_SIZE;
+        }
+    }
+
+    if (n->net_conf.tx_queue_size == 0) {
+        if (peer && peer->info->type == NET_CLIENT_DRIVER_VHOST_USER) {
+            n->net_conf.tx_queue_size = VIRTIO_NET_VHOST_USER_DEFAULT_SIZE;
+        } else {
+            n->net_conf.tx_queue_size = VIRTIO_NET_VQ_MAX_SIZE;
+        }
+    }
+}
+
 static int virtio_net_max_tx_queue_size(VirtIONet *n)
 {
     NetClientState *peer = n->nic_conf.peers.ncs[0];
@@ -630,11 +651,11 @@ static int virtio_net_max_tx_queue_size(VirtIONet *n)
      * Backends other than vhost-user don't support max queue size.
      */
     if (!peer) {
-        return VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE;
+        return VIRTIO_NET_VQ_MAX_SIZE;
     }
 
     if (peer->info->type != NET_CLIENT_DRIVER_VHOST_USER) {
-        return VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE;
+        return VIRTIO_NET_VQ_MAX_SIZE;
     }
 
     return VIRTIO_NET_VQ_MAX_SIZE;
@@ -3388,6 +3409,8 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     virtio_net_set_config_size(n, n->host_features);
     virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
 
+    virtio_net_set_default_queue_size(n);
+
     /*
      * We set a lower limit on RX queue size to what it always was.
      * Guests that want a smaller ring can always resize it without
@@ -3679,10 +3702,8 @@ static Property virtio_net_properties[] = {
                        TX_TIMER_INTERVAL),
     DEFINE_PROP_INT32("x-txburst", VirtIONet, net_conf.txburst, TX_BURST),
     DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx),
-    DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size,
-                       VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE),
-    DEFINE_PROP_UINT16("tx_queue_size", VirtIONet, net_conf.tx_queue_size,
-                       VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE),
+    DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, 0),
+    DEFINE_PROP_UINT16("tx_queue_size", VirtIONet, net_conf.tx_queue_size, 0),
     DEFINE_PROP_UINT16("host_mtu", VirtIONet, net_conf.mtu, 0),
     DEFINE_PROP_BOOL("x-mtu-bypass-backend", VirtIONet, mtu_bypass_backend,
                      true),
-- 
2.27.0