[PATCH 2/9] vhost-vdpa: mandate vhostdev

[Jason Wang <jasowang@redhat.com>]

vhost-dev is mandatory for vhost-vdpa to be initialized otherwise
net_vhost_vdpa_init will pass an uninitialized pointer to qemu_open()
which will lead a SIGSEV:

#0  0x0000555555c3a640 in strstart (str=str@entry=0x0, val=val@entry=0x555555dbcb65 "/dev/fdset/", ptr=ptr@entry=0x7fffffffdfb8) at ../util/cutils.c:77
#1  0x0000555555c572a7 in qemu_open (name=name@entry=0x0, flags=flags@entry=2) at ../util/osdep.c:294
#2  0x000055555584314a in net_vhost_vdpa_init (device=0x555555c81baa "vhost-vdpa", vhostdev=0x0, name=0x555556396600 "hn0", peer=0x0) at ../net/vhost-vdpa.c:187
#3  0x000055555584314a in net_init_vhost_vdpa (netdev=<optimized out>, name=0x555556396600 "hn0", peer=0x0, errp=<optimized out>) at ../net/vhost-vdpa.c:227
#4  0x000055555587e8c9 in net_client_init1 (netdev=0x555556398790, is_netdev=is_netdev@entry=true, errp=errp@entry=0x7fffffffe290) at ../net/net.c:1008
#5  0x000055555587ecc7 in net_client_init (opts=0x555556192ff0, is_netdev=<optimized out>, errp=0x7fffffffe290) at ../net/net.c:1113
#6  0x0000555555c33082 in qemu_opts_foreach
    (list=<optimized out>, func=func@entry=0x55555587ed50 <net_init_netdev>, opaque=opaque@entry=0x0, errp=errp@entry=0x7fffffffe290) at ../util/qemu-option.c:1172
#7  0x0000555555880057 in net_init_clients (errp=errp@entry=0x7fffffffe290) at ../net/net.c:1494
#8  0x0000555555a7f8e9 in qemu_init (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at ../softmmu/vl.c:4250
#9  0x00005555557f26cd in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at ../softmmu/main.c:49

Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 net/vhost-vdpa.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index bc0e0d2d35..b7221beaa1 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -206,7 +206,7 @@ static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
     }
     if (strcmp(netdev, name) == 0 &&
         !g_str_has_prefix(driver, "virtio-net-")) {
-        error_setg(errp, "vhost-vdpa requires frontend driver virtio-net-*");
+        error_setg(errp, "Vhost-vdpa requires frontend driver virtio-net-*");
         return -1;
     }
     return 0;
@@ -224,5 +224,9 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
                           (char *)name, errp)) {
         return -1;
     }
+    if (!opts->has_vhostdev) {
+        error_setg(errp, "vhost-vdpa requires vhostdev to be set");
+        return -1;
+    }
     return net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name, opts->vhostdev);
 }
-- 
2.20.1