Merge remote-tracking branch 'remotes/jasowang/tags/net-pull-request' into staging

# gpg: Signature made Fri 04 Jun 2021 08:26:16 BST
# gpg:                using RSA key EF04965B398D6211
# gpg: Good signature from "Jason Wang (Jason Wang on RedHat) <jasowang@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 215D 46F4 8246 689E C77F  3562 EF04 965B 398D 6211

* remotes/jasowang/tags/net-pull-request:
  MAINTAINERS: Added eBPF maintainers information.
  docs: Added eBPF documentation.
  virtio-net: Added eBPF RSS to virtio-net.
  ebpf: Added eBPF RSS loader.
  ebpf: Added eBPF RSS program.
  net: Added SetSteeringEBPF method for NetClientState.
  net/tap: Added TUNSETSTEERINGEBPF code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 116 insertions, 3 deletions

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 24d555e..44c1ed9 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -45,6 +45,7 @@ static const int kernel_feature_bits[] = {
     VIRTIO_NET_F_MTU,
     VIRTIO_F_IOMMU_PLATFORM,
     VIRTIO_F_RING_PACKED,
+    VIRTIO_NET_F_HASH_REPORT,
     VHOST_INVALID_FEATURE_BIT
 };
 
@@ -71,6 +72,8 @@ static const int user_feature_bits[] = {
     VIRTIO_NET_F_MTU,
     VIRTIO_F_IOMMU_PLATFORM,
     VIRTIO_F_RING_PACKED,
+    VIRTIO_NET_F_RSS,
+    VIRTIO_NET_F_HASH_REPORT,
 
     /* This bit implies RARP isn't sent by QEMU out of band */
     VIRTIO_NET_F_GUEST_ANNOUNCE,
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 05bd50d..bd7958b 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -737,8 +737,9 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, uint64_t features,
         return features;
     }
 
-    virtio_clear_feature(&features, VIRTIO_NET_F_RSS);
-    virtio_clear_feature(&features, VIRTIO_NET_F_HASH_REPORT);
+    if (!ebpf_rss_is_loaded(&n->ebpf_rss)) {
+        virtio_clear_feature(&features, VIRTIO_NET_F_RSS);
+    }
     features = vhost_net_get_features(get_vhost_net(nc->peer), features);
     vdev->backend_features = features;
 
@@ -1163,12 +1164,79 @@ static int virtio_net_handle_announce(VirtIONet *n, uint8_t cmd,
     }
 }
 
+static void virtio_net_detach_epbf_rss(VirtIONet *n);
+
 static void virtio_net_disable_rss(VirtIONet *n)
 {
     if (n->rss_data.enabled) {
         trace_virtio_net_rss_disable();
     }
     n->rss_data.enabled = false;
+
+    virtio_net_detach_epbf_rss(n);
+}
+
+static bool virtio_net_attach_ebpf_to_backend(NICState *nic, int prog_fd)
+{
+    NetClientState *nc = qemu_get_peer(qemu_get_queue(nic), 0);
+    if (nc == NULL || nc->info->set_steering_ebpf == NULL) {
+        return false;
+    }
+
+    return nc->info->set_steering_ebpf(nc, prog_fd);
+}
+
+static void rss_data_to_rss_config(struct VirtioNetRssData *data,
+                                   struct EBPFRSSConfig *config)
+{
+    config->redirect = data->redirect;
+    config->populate_hash = data->populate_hash;
+    config->hash_types = data->hash_types;
+    config->indirections_len = data->indirections_len;
+    config->default_queue = data->default_queue;
+}
+
+static bool virtio_net_attach_epbf_rss(VirtIONet *n)
+{
+    struct EBPFRSSConfig config = {};
+
+    if (!ebpf_rss_is_loaded(&n->ebpf_rss)) {
+        return false;
+    }
+
+    rss_data_to_rss_config(&n->rss_data, &config);
+
+    if (!ebpf_rss_set_all(&n->ebpf_rss, &config,
+                          n->rss_data.indirections_table, n->rss_data.key)) {
+        return false;
+    }
+
+    if (!virtio_net_attach_ebpf_to_backend(n->nic, n->ebpf_rss.program_fd)) {
+        return false;
+    }
+
+    return true;
+}
+
+static void virtio_net_detach_epbf_rss(VirtIONet *n)
+{
+    virtio_net_attach_ebpf_to_backend(n->nic, -1);
+}
+
+static bool virtio_net_load_ebpf(VirtIONet *n)
+{
+    if (!virtio_net_attach_ebpf_to_backend(n->nic, -1)) {
+        /* backend does't support steering ebpf */
+        return false;
+    }
+
+    return ebpf_rss_load(&n->ebpf_rss);
+}
+
+static void virtio_net_unload_ebpf(VirtIONet *n)
+{
+    virtio_net_attach_ebpf_to_backend(n->nic, -1);
+    ebpf_rss_unload(&n->ebpf_rss);
 }
 
 static uint16_t virtio_net_handle_rss(VirtIONet *n,
@@ -1283,6 +1351,25 @@ static uint16_t virtio_net_handle_rss(VirtIONet *n,
         goto error;
     }
     n->rss_data.enabled = true;
+
+    if (!n->rss_data.populate_hash) {
+        if (!virtio_net_attach_epbf_rss(n)) {
+            /* EBPF must be loaded for vhost */
+            if (get_vhost_net(qemu_get_queue(n->nic)->peer)) {
+                warn_report("Can't load eBPF RSS for vhost");
+                goto error;
+            }
+            /* fallback to software RSS */
+            warn_report("Can't load eBPF RSS - fallback to software RSS");
+            n->rss_data.enabled_software_rss = true;
+        }
+    } else {
+        /* use software RSS for hash populating */
+        /* and detach eBPF if was loaded before */
+        virtio_net_detach_epbf_rss(n);
+        n->rss_data.enabled_software_rss = true;
+    }
+
     trace_virtio_net_rss_enable(n->rss_data.hash_types,
                                 n->rss_data.indirections_len,
                                 temp.b);
@@ -1668,7 +1755,7 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
         return -1;
     }
 
-    if (!no_rss && n->rss_data.enabled) {
+    if (!no_rss && n->rss_data.enabled && n->rss_data.enabled_software_rss) {
         int index = virtio_net_process_rss(nc, buf, size);
         if (index >= 0) {
             NetClientState *nc2 = qemu_get_subqueue(n->nic, index);
@@ -2772,6 +2859,19 @@ static int virtio_net_post_load_device(void *opaque, int version_id)
     }
 
     if (n->rss_data.enabled) {
+        n->rss_data.enabled_software_rss = n->rss_data.populate_hash;
+        if (!n->rss_data.populate_hash) {
+            if (!virtio_net_attach_epbf_rss(n)) {
+                if (get_vhost_net(qemu_get_queue(n->nic)->peer)) {
+                    warn_report("Can't post-load eBPF RSS for vhost");
+                } else {
+                    warn_report("Can't post-load eBPF RSS - "
+                                "fallback to software RSS");
+                    n->rss_data.enabled_software_rss = true;
+                }
+            }
+        }
+
         trace_virtio_net_rss_enable(n->rss_data.hash_types,
                                     n->rss_data.indirections_len,
                                     sizeof(n->rss_data.key));
@@ -3352,6 +3452,10 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     n->qdev = dev;
 
     net_rx_pkt_init(&n->rx_pkt, false);
+
+    if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
+        virtio_net_load_ebpf(n);
+    }
 }
 
 static void virtio_net_device_unrealize(DeviceState *dev)
@@ -3360,6 +3464,10 @@ static void virtio_net_device_unrealize(DeviceState *dev)
     VirtIONet *n = VIRTIO_NET(dev);
     int i, max_queues;
 
+    if (virtio_has_feature(n->host_features, VIRTIO_NET_F_RSS)) {
+        virtio_net_unload_ebpf(n);
+    }
+
     /* This will stop vhost backend if appropriate. */
     virtio_net_set_status(vdev, 0);
 
@@ -3403,6 +3511,8 @@ static void virtio_net_instance_init(Object *obj)
     device_add_bootindex_property(obj, &n->nic_conf.bootindex,
                                   "bootindex", "/ethernet-phy@0",
                                   DEVICE(n));
+
+    ebpf_rss_init(&n->ebpf_rss);
 }
 
 static int virtio_net_pre_save(void *opaque)