From 9d0ebf8d2574038414a70a62f5fe4e69aaa879bc Mon Sep 17 00:00:00 2001
From: Rob Bradford <robert.bradford@intel.com>
Date: Thu, 3 Sep 2020 10:37:36 +0100
Subject: [PATCH] virtio-devices: vhost-user-net: Port to VirtioCommon for
 feature handling

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
---
 virtio-devices/src/vhost_user/net.rs | 32 +++++++++++++---------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/virtio-devices/src/vhost_user/net.rs b/virtio-devices/src/vhost_user/net.rs
index 5f4db692f..359741db8 100644
--- a/virtio-devices/src/vhost_user/net.rs
+++ b/virtio-devices/src/vhost_user/net.rs
@@ -4,7 +4,9 @@
 use super::super::net_util::{
     build_net_config_space, CtrlVirtio, NetCtrlEpollHandler, VirtioNetConfig,
 };
-use super::super::{ActivateError, ActivateResult, Queue, VirtioDevice, VirtioDeviceType};
+use super::super::{
+    ActivateError, ActivateResult, Queue, VirtioCommon, VirtioDevice, VirtioDeviceType,
+};
 use super::handler::*;
 use super::vu_common_ctrl::*;
 use super::{Error, Result};
@@ -34,12 +36,11 @@ struct SlaveReqHandler {}
 impl VhostUserMasterReqHandler for SlaveReqHandler {}
 
 pub struct Net {
+    common: VirtioCommon,
     id: String,
     vhost_user_net: Master,
     kill_evt: Option<EventFd>,
     pause_evt: Option<EventFd>,
-    avail_features: u64,
-    acked_features: u64,
     backend_features: u64,
     config: VirtioNetConfig,
     queue_sizes: Vec<u16>,
@@ -147,11 +148,13 @@ impl Net {
 
         Ok(Net {
             id,
+            common: VirtioCommon {
+                avail_features,
+                acked_features,
+            },
             vhost_user_net,
             kill_evt: None,
             pause_evt: None,
-            avail_features,
-            acked_features,
             backend_features,
             config,
             queue_sizes: vec![vu_cfg.queue_size; queue_num],
@@ -186,19 +189,11 @@ impl VirtioDevice for Net {
     }
 
     fn features(&self) -> u64 {
-        self.avail_features
+        self.common.avail_features
     }
 
     fn ack_features(&mut self, value: u64) {
-        let mut v = value;
-        // Check if the guest is ACK'ing a feature that we didn't claim to have.
-        let unrequested_features = v & !self.avail_features;
-        if unrequested_features != 0 {
-            warn!("Received acknowledge request for unknown feature: {:x}", v);
-            // Don't count these features as acked.
-            v &= !unrequested_features;
-        }
-        self.acked_features |= v;
+        self.common.ack_features(value)
     }
 
     fn read_config(&self, offset: u64, data: &mut [u8]) {
@@ -254,7 +249,10 @@ impl VirtioDevice for Net {
 
         let queue_num = queue_evts.len();
 
-        if (self.acked_features & 1 << virtio_net::VIRTIO_NET_F_CTRL_VQ) != 0 && queue_num % 2 != 0
+        if self
+            .common
+            .feature_acked(virtio_net::VIRTIO_NET_F_CTRL_VQ.into())
+            && queue_num % 2 != 0
         {
             let cvq_queue = queues.remove(queue_num - 1);
             let cvq_queue_evt = queue_evts.remove(queue_num - 1);
@@ -298,7 +296,7 @@ impl VirtioDevice for Net {
             queues,
             queue_evts,
             &interrupt_cb,
-            self.acked_features & self.backend_features,
+            self.common.acked_features & self.backend_features,
         )
         .map_err(ActivateError::VhostUserNetSetup)?;