From 0e07198ea3d899b0e7946b1a3d2a439d53415289 Mon Sep 17 00:00:00 2001
From: Akihiko Odaki <akihiko.odaki@daynix.com>
Date: Sun, 28 Apr 2024 16:00:55 +0900
Subject: [PATCH] virtio-net: Unify the logic to update NIC state for RSS

The code to attach or detach the eBPF program to RSS were duplicated so
unify them into one function to save some code.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c | 90 ++++++++++++++++++---------------------------
 1 file changed, 36 insertions(+), 54 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 345ef9a8fd..8464eb4082 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1232,18 +1232,6 @@ 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);
@@ -1291,6 +1279,40 @@ static void virtio_net_detach_epbf_rss(VirtIONet *n)
     virtio_net_attach_ebpf_to_backend(n->nic, -1);
 }
 
+static void virtio_net_commit_rss_config(VirtIONet *n)
+{
+    if (n->rss_data.enabled) {
+        n->rss_data.enabled_software_rss = n->rss_data.populate_hash;
+        if (n->rss_data.populate_hash) {
+            virtio_net_detach_epbf_rss(n);
+        } else if (!virtio_net_attach_epbf_rss(n)) {
+            if (get_vhost_net(qemu_get_queue(n->nic)->peer)) {
+                warn_report("Can't load eBPF RSS for vhost");
+            } else {
+                warn_report("Can't 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));
+    } else {
+        virtio_net_detach_epbf_rss(n);
+        trace_virtio_net_rss_disable();
+    }
+}
+
+static void virtio_net_disable_rss(VirtIONet *n)
+{
+    if (!n->rss_data.enabled) {
+        return;
+    }
+
+    n->rss_data.enabled = false;
+    virtio_net_commit_rss_config(n);
+}
+
 static bool virtio_net_load_ebpf_fds(VirtIONet *n)
 {
     int fds[EBPF_RSS_MAX_FDS] = { [0 ... EBPF_RSS_MAX_FDS - 1] = -1};
@@ -1455,28 +1477,7 @@ 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);
+    virtio_net_commit_rss_config(n);
     return queue_pairs;
 error:
     trace_virtio_net_rss_error(err_msg, err_value);
@@ -3076,26 +3077,7 @@ 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));
-    } else {
-        trace_virtio_net_rss_disable();
-    }
+    virtio_net_commit_rss_config(n);
     return 0;
 }