Hi!
The patch f56a12475ff1b8aa61210d08522c3c8aaf0e2648 "vhost: backend masking
support" breaks virtio-net + vhost=on on PPC64 platform.
The problem command line is:
1) -netdev tap,id=tapnet,ifname=tap0,script=qemu-ifup.sh,vhost=on \
-device virtio-net-pci,netdev=tapnet,addr=0.0 \
Without the patch, the eth0 in the guest works fine, with the patch it
simply does not. The guest's eth0 also works with the following configs:
2) new -netdev interface with vhost=off:
-netdev tap,id=tapnet,ifname=tap0,script=qemu-ifup.sh \
-device virtio-net-pci,netdev=tapnet,addr=0.0
3) old -net interface with vhost=on:
-net tap,ifname=tap0,script=qemu-ifup.sh,vhost=on \
-net nic,model=virtio,addr=0:0:0
4) old -net interface with vhost=off:
-net tap,ifname=tap0,script=qemu-ifup.sh \
-net nic,model=virtio,addr=0:0:0
I run http://junkcode.samba.org/ftp/unpacked/junkcode/socklib/ on
10Gb ethernet and observe 1020MB/s for 1) (without the patch),
800MB/s for 2), 70MB/s for 3) and 4).
The virtio features (cat /sys/bus/virtio/devices/virtio0/features)
for 1) and 2) are:
"1100011111111111111100000000110000000000000000000000000000000000"
and for 3) and 4) they are:
"0000011000000001111100000000110000000000000000000000000000000000"
I guess this is because the old -net interface creates
an internal hub as "info qtree" shows vlan=0 and netdev=hub0port1
while the new -netdev interface does not seem to create any internal
hub (vlan=<null>, netdev=tapnet). btw why are the configs so different?
The network config is below. Both host and guest are running 3.8 kernel.
The qemu tree from qemu.org/master still has this problem.
What am I missing? Thanks.
The full command line is like below plus the network config from
the examples above:
sudo qemu-impreza/ppc64-softmmu/qemu-system-ppc64 -m 1024 -machine
pseries,kernel_irqchip=on -trace events=trace_events \
-nographic -vga none -enable-kvm -kernel vml38_64k -initrd 1.cpio
This is the host config:
[aik@vpl2 ~]$ cat qemu-ifup.sh
#! /bin/sh
/sbin/ifconfig $1 0.0.0.0 promisc up
/usr/sbin/brctl addif brtest $1
[aik@vpl2 ~]$ brctl show
bridge name bridge id STP enabled interfaces
brtest 8000.00145e992e88 no eth0
[aik@vpl2 ~]$ ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::214:5eff:fe99:2e88 prefixlen 64 scopeid 0x20<link>
ether 00:14:5e:99:2e:88 txqueuelen 1000 (Ethernet)
RX packets 1781219 bytes 124692636 (118.9 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 13734906 bytes 20755102658 (19.3 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 49 memory 0x3c0500800000-3c0500800fff
[aik@vpl2 ~]$ lspci -vs 1:1:0.0
0001:01:00.0 Ethernet controller: Chelsio Communications Inc T310 10GbE
Single Port Adapter
Subsystem: IBM Device 038c
Flags: bus master, fast devsel, latency 0, IRQ 49
Memory at 3c0500800000 (64-bit, non-prefetchable) [size=4K]
Memory at 3c0500000000 (64-bit, non-prefetchable) [size=8M]
Memory at 3c0500801000 (64-bit, non-prefetchable) [size=4K]
[virtual] Expansion ROM at 3c0500c00000 [disabled] [size=512K]
Capabilities: <access denied>
Kernel driver in use: cxgb3
[aik@vpl2 ~]$ ls -l /sys/bus/pci/devices/0001\:01\:00.0/net/
total 0
drwxr-xr-x. 5 root root 0 Mar 5 12:59 eth0
[aik@vpl2 ~]$ uname -a
Linux vpl2.ozlabs.ibm.com 3.8.0-kvm-64k-aik+ #239 SMP Tue Mar 5 12:50:05
EST 2013 ppc64 ppc64 ppc64 GNU/Linux
This is the running guest:
root@erif_root:~# lspci -v
00:00.0 Ethernet controller: Qumranet, Inc. Virtio network device
Subsystem: Qumranet, Inc. Device 0001
Flags: bus master, fast devsel, latency 0, IRQ 19
I/O ports at 0020 [size=32]
Memory at 100b0000000 (32-bit, non-prefetchable) [size=4K]
Expansion ROM at 100b0010000 [disabled] [size=64K]
Capabilities: [40] MSI-X: Enable+ Count=3 Masked-
Kernel driver in use: virtio-pci
root@erif_root:~# ifconfig -a
eth0 Link encap:Ethernet HWaddr 52:54:00:12:34:56
inet addr:172.20.1.2 Bcast:172.20.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:36 errors:0 dropped:6 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2268 (2.2 KiB) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
root@erif_root:~# uname -a
Linux erif_root 3.8.0-aik-guest+ #262 SMP Mon Mar 4 15:58:55 EST 2013 ppc64
GNU/Linux
--
Alexey