diff mbox

[dpdk-dev,2/9] net/virtio: revert "do not falsely claim to do IP checksum"

Message ID 20170831134015.1383-3-olivier.matz@6wind.com (mailing list archive)
State Superseded, archived
Delegated to: Yuanhan Liu
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Olivier Matz Aug. 31, 2017, 1:40 p.m. UTC 
  This reverts
commit 4dab342b7522 ("net/virtio: do not falsely claim to do IP checksum").

The description of rxmode->hw_ip_checksum is:

     hw_ip_checksum   : 1, /**< IP/UDP/TCP checksum offload enable. */

Despite its name, this field can be set by an application to enable L3
and L4 checksums. In case of virtio, only L4 checksum is supported and
L3 checksums flags will always be set to "unknown".

Fixes: 4dab342b7522 ("net/virtio: do not falsely claim to do IP checksum")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 drivers/net/virtio/virtio_ethdev.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

Comments

Olivier Matz Aug. 31, 2017, 1:47 p.m. UTC | #1 
Validation:


Platform description
--------------------

guest (dpdk)
+----------------+
|                |
|                |
|    port0       |
+----------------+
       |
       | virtio
       |
+----------------+
|     tap0       |
|                |
|                |
+----------------+
host (linux, vhost-net)

Host configuration
------------------

Start qemu with:

- a ne2k management interface to avoi any conflict with dpdk
- a virtio net device, connected to a tap interface through vhost-net

  /usr/bin/qemu-system-x86_64 -k fr -daemonize --enable-kvm -m 2G -cpu host \
    -smp 3 -serial telnet::40564,server,nowait -serial null \
    -qmp tcp::44340,server,nowait -monitor telnet::49229,server,nowait \
    -device ne2k_pci,mac=de:ad:de:01:02:03,netdev=user.0,addr=03 \
    -netdev user,id=user.0,hostfwd=tcp::34965-:22 \
    -netdev type=tap,id=vhostnet0,script=no,vhost=on,queues=8 \
    -device virtio-net-pci,netdev=vhostnet0,mq=on,vectors=17 \
    -hda "${VM_PATH}/ubuntu-16.04-template.qcow2" \
    -snapshot -vga none -display none

Guest configuration
-------------------

Compile dpdk:

  cd dpdk.org
  make config T=x86_64-native-linuxapp-gcc
  sed -i 's,CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_INIT=n,CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_INIT=y,' build/.config
  sed -i 's,CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_DRIVER=n,CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_DRIVER=y,' build/.config
  make -j4

Prepare environment:

  mkdir -p /mnt/huge
  mount -t hugetlbfs nodev /mnt/huge
  echo 256 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
  modprobe uio_pci_generic
  python usertools/dpdk-devbind.py -b uio_pci_generic 0000:00:02.0

  ./build/app/testpmd -l 0,1 --log-level 8 -- --total-num-mbufs=16384 \
    -i --port-topology=chained --disable-hw-vlan-filter \
    --disable-hw-vlan-strip --enable-rx-cksum --enable-lro \
    --txqflags=0

Before the reverts (patch 1 and 2 of the patchset)
------------------

testpmd cannot start

...
PMD: virtio_dev_configure(): virtio does not support IP checksum

After the reverts
-----------------

 testpmd starts properly, and receives packets with csum flags

testpmd> set fwd rxonly
Set rxonly packet forwarding mode
testpmd> set verbose 1
Change verbose level from 0 to 1
testpmd> start
# tcp packet sent from the host
port 0/queue 0: received 1 packets
  src=16:9A:CA:76:89:BC - dst=52:54:00:12:34:56 - type=0x0800 - length=74 - nb_segs=1 - hw ptype: L2_ETHER L3_IPV4 L4_TCP  - sw ptype: L2_ETHER L3_IPV4 L4_TCP  - l2_len=14 - l3_len=20 - l4_len=40 - Receive queue=0x0
  ol_flags: PKT_RX_L4_CKSUM_NONE PKT_RX_IP_CKSUM_UNKNOWN
diff mbox

Patch

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index eb2d95acd..7a84817e5 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1671,12 +1671,13 @@  virtio_dev_configure(struct rte_eth_dev *dev)
 			return ret;
 	}
 
-	/* Virtio does L4 checksum but not L3! */
-	if (rxmode->hw_ip_checksum) {
-		PMD_DRV_LOG(NOTICE,
-			    "virtio does not support IP checksum");
-		return -ENOTSUP;
-	}
+	/* The name hw_ip_checksum is a bit confusing since it can be
+	 * set by the application to request L3 and/or L4 checksums. In
+	 * case of virtio, only L4 checksum is supported.
+	 */
+	if (rxmode->hw_ip_checksum)
+		req_features |= (1ULL << VIRTIO_NET_F_GUEST_CSUM);
+
 	if (rxmode->enable_lro)
 		req_features |=
 			(1ULL << VIRTIO_NET_F_GUEST_TSO4) |
@@ -1689,6 +1690,13 @@  virtio_dev_configure(struct rte_eth_dev *dev)
 			return ret;
 	}
 
+	if (rxmode->hw_ip_checksum &&
+		!vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_CSUM)) {
+		PMD_DRV_LOG(NOTICE,
+			"rx checksum not available on this host");
+		return -ENOTSUP;
+	}
+
 	if (rxmode->enable_lro &&
 		(!vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_TSO4) ||
 			!vtpci_with_feature(hw, VIRTIO_NET_F_GUEST_TSO4))) {