From 8bcfea21b40fea3155bd311c03464bb10955ae36 Mon Sep 17 00:00:00 2001
From: Chen Qun <kuhn.chenqun@huawei.com>
Date: Fri, 11 Feb 2022 18:49:21 +0800
Subject: [PATCH] vhost-user: Set the acked_features to vm's featrue

Fix the problem when vm restart, the ovs restart and lead to the net
unreachable. The soluation is set the acked_features to vm's featrue
just the same as guest virtio-net mod load.

Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>
---
 ...t-the-acked_features-to-vm-s-featrue.patch | 96 +++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 vhost-user-Set-the-acked_features-to-vm-s-featrue.patch

diff --git a/vhost-user-Set-the-acked_features-to-vm-s-featrue.patch b/vhost-user-Set-the-acked_features-to-vm-s-featrue.patch
new file mode 100644
index 0000000..63c0353
--- /dev/null
+++ b/vhost-user-Set-the-acked_features-to-vm-s-featrue.patch
@@ -0,0 +1,96 @@
+From 12af29806ba8ede96567e4df9223f0c02669727c Mon Sep 17 00:00:00 2001
+From: Jinhua Cao <caojinhua1@huawei.com>
+Date: Fri, 11 Feb 2022 18:49:21 +0800
+Subject: [PATCH] vhost-user: Set the acked_features to vm's featrue
+
+Fix the problem when vm restart, the ovs restart and lead to the net
+unreachable. The soluation is set the acked_features to vm's featrue
+just the same as guest virtio-net mod load.
+
+Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>
+---
+ hw/net/vhost_net.c | 58 +++++++++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 57 insertions(+), 1 deletion(-)
+
+diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
+index a60f7cef9a..e8a79db94d 100644
+--- a/hw/net/vhost_net.c
++++ b/hw/net/vhost_net.c
+@@ -152,9 +152,26 @@ static int vhost_net_get_fd(NetClientState *backend)
+     }
+ }
+ 
++static uint64_t vhost_get_mask_features(const int *feature_bits, uint64_t features)
++{
++    const int *bit = feature_bits;
++    uint64_t out_features = 0;
++
++    while (*bit != VHOST_INVALID_FEATURE_BIT) {
++        uint64_t bit_mask = (1ULL << *bit);
++        if (features & bit_mask) {
++            out_features |= bit_mask;
++        }
++        bit++;
++    }
++    return out_features;
++}
++
+ struct vhost_net *vhost_net_init(VhostNetOptions *options)
+ {
+     int r;
++    VirtIONet *n;
++    VirtIODevice *vdev;
+     bool backend_kernel = options->backend_type == VHOST_BACKEND_TYPE_KERNEL;
+     struct vhost_net *net = g_new0(struct vhost_net, 1);
+     uint64_t features = 0;
+@@ -180,7 +197,46 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
+         net->backend = r;
+         net->dev.protocol_features = 0;
+     } else {
+-        net->dev.backend_features = 0;
++        /* for ovs restart when vm start.
++         * Normal situation:
++         * 1.vm start.
++         * 2.vhost_net_init init ok, then dev.acked_features is 0x40000000.
++         * 3.guest virtio-net mod load. qemu will call virtio_net_set_features set
++         * dev.acked_features to 0x40408000.
++         * 4.feature set to ovs's vhostuser(0x40408000).
++         * 5.ovs restart.
++         * 6.vhost_user_stop will save net->dev.acked_features(0x40408000) to
++         * VhostUserState's acked_features(0x40408000).
++         * 7.restart ok.
++         * 8.vhost_net_init fun call vhost_user_get_acked_features get the save
++         * features, and set to net->dev.acked_features.
++         * Abnormal situation:
++         * 1.vm start.
++         * 2.vhost_net_init init ok, then dev.acked_features is 0x40000000.
++         * 3.ovs restart.
++         * 4.vhost_user_stop will save net->dev.acked_features(0x40000000) to
++         * VhostUserState's acked_features(0x40000000).
++         * 5.guest virtio-net mod load. qemu will call virtio_net_set_features set
++         * dev.acked_features to 0x40408000.
++         * 6.restart ok.
++         * 7.vhost_net_init fun call vhost_user_get_acked_features get the save
++         * features(0x40000000), and set to net->dev.acked_features(0x40000000).
++         * 8.feature set to ovs's vhostuser(0x40000000).
++         *
++         * in abnormal situation, qemu set the wrong features to ovs's vhostuser,
++         * then the vm's network will be down.
++         * in abnormal situation, we found it just lost the guest feartures in
++         * acked_features, so hear we set the acked_features to vm's featrue
++         * just the same as guest virtio-net mod load.
++         */
++        if (options->net_backend->peer) {
++            n = qemu_get_nic_opaque(options->net_backend->peer);
++            vdev = VIRTIO_DEVICE(n);
++            net->dev.backend_features = vhost_get_mask_features(vhost_net_get_feature_bits(net),
++                                                                vdev->guest_features);
++        } else {
++            net->dev.backend_features = 0;
++        }
+         net->dev.protocol_features = 0;
+         net->backend = -1;
+ 
+-- 
+2.27.0
+