From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marvin Liu <yong.liu@intel.com>
Subject: [PATCH v3] examples/vhost: workaround qemu abort
Date: Wed, 25 Jul 2018 18:25:56 +0800
Message-ID: <20180725102556.68604-1-yong.liu@intel.com>
References: <20180724151649.44490-1-yong.liu@intel.com>
Cc: Marvin Liu <yong.liu@intel.com>
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Current qemu vhost net ring start has a dependency on feature bit
VHOST_USER_F_PROTOCOL_FEATURES. Without this feature, vhost ring can't
enabled and ioevent fd won't be deleted after vhost device stop. That
will cause qemu abort when reloading driver. Work around qemu issues by
enabling feature bit in vhost user backend.

Signed-off-by: Marvin Liu <yong.liu@intel.com>

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index 2175c1186..8573004dd 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -1520,7 +1520,10 @@ main(int argc, char *argv[])
 		}
 
 		if (builtin_net_driver)
-			rte_vhost_driver_set_features(file, VIRTIO_NET_FEATURES);
+			/* Workaround for qemu vhost net device startup */
+			rte_vhost_driver_set_features(file,
+				VIRTIO_NET_FEATURES |
+				1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
 
 		if (mergeable == 0) {
 			rte_vhost_driver_disable_features(file,
-- 
2.17.0