net:udpgro_frglist.sh in ubuntu_kernel_selftests failed on K-KVM (RTNETLINK answers: Operation not supported)

[Po-Hsu Lin]

With bug 2000708 fix, this test on K-kvm is now failing with:

 Running 'make run_tests -C net TEST_PROGS=udpgro_frglist.sh TEST_GEN_PROGS='' TEST_CUSTOM_PROGS='''
 make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/net'
 make --no-builtin-rules ARCH=x86 -C ../../../.. headers_install
 make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
   INSTALL ./usr/include
 make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
 TAP version 13
 1..1
 # selftests: net: udpgro_frglist.sh
 # ipv6
 # tcp - over veth touching data
 # -l 4 -6 -D 2001:db8::1 -t rx -4 -t
 # RTNETLINK answers: Operation not supported
 # RTNETLINK answers: Operation not supported
 # We have an error talking to the kernel
 # RTNETLINK answers: Operation not supported
 # We have an error talking to the kernel
 # -4 -t
 # ./udpgso_bench_tx: connect: Connection refused
 # udp gso - over veth touching data
 # -l 4 -6 -D 2001:db8::1 -u -S 0 rx -4 -v
 # RTNETLINK answers: Operation not supported
 # RTNETLINK answers: Operation not supported
 # We have an error talking to the kernel
 # RTNETLINK answers: Operation not supported
 # We have an error talking to the kernel
 # -4 -v
 # udp tx: 699 MB/s 11870 calls/s 11870 msg/s
 # udp tx: 1053 MB/s 17861 calls/s 17861 msg/s
 # udp tx: 1240 MB/s 21044 calls/s 21044 msg/s
 # udp tx: 1244 MB/s 21100 calls/s 21100 msg/s
 # udp gso and gro - over veth touching data
 # -l 4 -6 -D 2001:db8::1 -S 0 rx -4 -G
 # RTNETLINK answers: Operation not supported
 # RTNETLINK answers: Operation not supported
 # We have an error talking to the kernel
 # RTNETLINK answers: Operation not supported
 # We have an error talking to the kernel
 # -4 -G
 # ./udpgso_bench_tx: sendmsg: Connection refused
 not ok 1 selftests: net: udpgro_frglist.sh # exit=1
 make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/net'

run_tcp() test is the first one complaining "RTNETLINK answers: Operation not supported", which is:
+ ./in_netns.sh ./udpgro_frglist.sh __subprocess -l 4 -6 -D 2001:db8::1 -u -S 0 rx -4 -v
RTNETLINK answers: Operation not supported
RTNETLINK answers: Operation not supported
We have an error talking to the kernel
RTNETLINK answers: Operation not supported
We have an error talking to the kernel