[RFC PATCH 3/4] virtio-net: Add hash type options

[Akihiko Odaki]

By default, virtio-net limits the hash types that will be advertised to
the guest so that all hash types are covered by the offloading
capability the client provides. This change allows to override this
behavior and to advertise hash types that require user-space hash
calculation by specifying "on" for the corresponding properties.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 include/hw/virtio/virtio-net.h |  1 +
 hw/net/virtio-net.c            | 48 +++++++++++++++++++++++++++++++---
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index deba793ec2..33857dd3c2 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -142,6 +142,7 @@ typedef struct VirtioNetRssData {
     uint32_t runtime_hash_types;
     uint32_t supported_hash_types;
     uint32_t peer_hash_types;
+    OnOffAuto specified_hash_types[8];
     uint8_t key[VIRTIO_NET_RSS_MAX_KEY_SIZE];
     uint16_t indirections_len;
     uint16_t *indirections_table;
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 3bf1fec2ac..9146a65aa4 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1379,16 +1379,31 @@ static bool virtio_net_configure_rss_host(VirtIONet *n, 
Error **errp)
 {
     NetVnetHashCap cap;
 
+    n->rss_data.supported_hash_types = VIRTIO_NET_RSS_SUPPORTED_HASHES;
+
     if (qemu_get_vnet_hash_cap(qemu_get_queue(n->nic)->peer, &cap) &&
         cap.max_indirection_table_length >= VIRTIO_NET_RSS_MAX_TABLE_LEN) {
         n->rss_data.peer_hash_available = true;
-        n->rss_data.supported_hash_types = cap.types;
         n->rss_data.peer_hash_types = cap.types;
 
-        return true;
+        for (size_t i = 0; ; i++) {
+            if (i >= ARRAY_SIZE(n->rss_data.specified_hash_types)) {
+                n->rss_data.supported_hash_types = cap.types;
+                break;
+            }
+
+            if (n->rss_data.specified_hash_types[i] == ON_OFF_AUTO_ON &&
+                !(cap.types & BIT(i + 1))) {
+                break;
+            }
+        }
     }
 
-    n->rss_data.supported_hash_types = VIRTIO_NET_RSS_SUPPORTED_HASHES;
+    for (size_t i = 0; i < ARRAY_SIZE(n->rss_data.specified_hash_types); i++) {
+        if (n->rss_data.specified_hash_types[i] == ON_OFF_AUTO_OFF) {
+            n->rss_data.supported_hash_types &= ~BIT(i + 1);
+        }
+    }
 
     return virtio_net_commit_rss_host_config(n, errp);
 }
@@ -4013,6 +4028,33 @@ static Property virtio_net_properties[] = {
     DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN),
     DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
     DEFINE_PROP_BOOL("failover", VirtIONet, failover, false),
+    DEFINE_PROP_ON_OFF_AUTO("hash-ipv4", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_IPv4 - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-tcp4", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_TCPv4 - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-udp4", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_UDPv4 - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-ipv6", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_IPv6 - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-tcp6", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_TCPv6 - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-udp6", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_UDPv6 - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-ipv6ex", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_IPv6_EX - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-tcp6ex", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_TCPv6_EX - 1],
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_ON_OFF_AUTO("hash-udp6ex", VirtIONet,
+                            
rss_data.specified_hash_types[VIRTIO_NET_HASH_REPORT_UDPv6_EX - 1],
+                            ON_OFF_AUTO_AUTO),
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.42.0