[Qemu-devel] [ RFC Patch v4 1/3] virtio-net rsc: add a new host offload(rsc) feature bit

[wexu]

From: Wei Xu <address@hidden>

A new feature bit 'VIRTIO_NET_F_GUEST_RSC' is introduced to support WHQL
Receive-Segment-Offload test, this feature will coalesce tcp packets in
IPv4/6 for userspace virtio-net driver.

This feature can be enabled either by 'ACK' the feature when loading
the driver in the guest, or by sending the 'VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET'
command to the host via control queue.

Signed-off-by: Wei Xu <address@hidden>
---
 hw/net/virtio-net.c                         | 29 +++++++++++++++++++++++++++--
 include/standard-headers/linux/virtio_net.h |  1 +
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 5798f87..bd91a4b 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -537,6 +537,7 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, 
uint64_t features,
         virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_TSO4);
         virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_TSO6);
         virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_ECN);
+        virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_RSC);
     }
 
     if (!peer_has_vnet_hdr(n) || !peer_has_ufo(n)) {
@@ -582,7 +583,8 @@ static uint64_t 
virtio_net_guest_offloads_by_features(uint32_t features)
         (1ULL << VIRTIO_NET_F_GUEST_TSO4) |
         (1ULL << VIRTIO_NET_F_GUEST_TSO6) |
         (1ULL << VIRTIO_NET_F_GUEST_ECN)  |
-        (1ULL << VIRTIO_NET_F_GUEST_UFO);
+        (1ULL << VIRTIO_NET_F_GUEST_UFO)  |
+        (1ULL << VIRTIO_NET_F_GUEST_RSC);
 
     return guest_offloads_mask & features;
 }
@@ -1089,7 +1091,8 @@ static int receive_filter(VirtIONet *n, const uint8_t 
*buf, int size)
     return 0;
 }
 
-static ssize_t virtio_net_receive(NetClientState *nc, const uint8_t *buf, 
size_t size)
+static ssize_t virtio_net_do_receive(NetClientState *nc,
+                                     const uint8_t *buf, size_t size)
 {
     VirtIONet *n = qemu_get_nic_opaque(nc);
     VirtIONetQueue *q = virtio_net_get_subqueue(nc);
@@ -1685,6 +1688,26 @@ static int virtio_net_load_device(VirtIODevice *vdev, 
QEMUFile *f,
     return 0;
 }
 
+
+static ssize_t virtio_net_rsc_receive(NetClientState *nc,
+                                      const uint8_t *buf, size_t size)
+{
+    return virtio_net_do_receive(nc, buf, size);
+}
+
+static ssize_t virtio_net_receive(NetClientState *nc,
+                                  const uint8_t *buf, size_t size)
+{
+    VirtIONet *n;
+
+    n = qemu_get_nic_opaque(nc);
+    if (n->curr_guest_offloads & VIRTIO_NET_F_GUEST_RSC) {
+        return virtio_net_rsc_receive(nc, buf, size);
+    } else {
+        return virtio_net_do_receive(nc, buf, size);
+    }
+}
+
 static NetClientInfo net_virtio_info = {
     .type = NET_CLIENT_OPTIONS_KIND_NIC,
     .size = sizeof(NICState),
@@ -1909,6 +1932,8 @@ 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_BIT("guest_rsc", VirtIONet, host_features,
+                    VIRTIO_NET_F_GUEST_RSC, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/standard-headers/linux/virtio_net.h 
b/include/standard-headers/linux/virtio_net.h
index a78f33e..5b95762 100644
--- a/include/standard-headers/linux/virtio_net.h
+++ b/include/standard-headers/linux/virtio_net.h
@@ -55,6 +55,7 @@
 #define VIRTIO_NET_F_MQ        22      /* Device supports Receive Flow
                                         * Steering */
 #define VIRTIO_NET_F_CTRL_MAC_ADDR 23  /* Set MAC address */
+#define VIRTIO_NET_F_GUEST_RSC  24      /* Guest can coalesce tcp packets */
 
 #ifndef VIRTIO_NET_NO_LEGACY
 #define VIRTIO_NET_F_GSO       6       /* Host handles pkts w/ any GSO type */
-- 
2.5.0