编译2.6.8内核后的问题

ygl

编译2.6.8内核成功，安装内核成功，重新启动，出现如下提示：

IP: routing cache hash table of 128 buckets, 4Kbytes
TCP: Hash tables configured (established 2048 bind 585)
ip_tables: (C) 2000-2002 Netfilter core team
ipt_recent v0.3.1: Stephen Frost <sfrost@snowman.net>. http://snowman.net/proj
cts/ipt_recent/
IPVS: Registered protocols ()
IPVS: Connection hash table configured (size=65536, memory=512Kbytes)
IPVS: ipvs loaded.
Initializing IPsec netlink socket
NET: Registered protocol family 1
NET: Registered protocol family 10
IPv6 over IPv4 tunneling driver
ip6_tables: (C) 2000-2002 Netfilter core team
NET: Registered protocol family 17
NET: Registered protocol family 8
NET: Registered protocol family 20
md: Autodetecting RAID arrays.
md: autorun ...
md: ... autorun DONE.
Root-NFS: No NFS server available, giving up.
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "LABEL=/" or unknown-block(2,0)
Please append a correct "root=" boot option
Kernel panic: VFS: Unable to mount root fs on unknown-block(2,0)


到此处停止，不再进行下面的加载，
我是在虚拟机安装的linux,是什么原因？