Thread (18 messages) 18 messages, 3 authors, 2020-09-30

Re: [PATCH 1/2] virtio-net: don't disable guest csum when disable LRO

From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2020-09-28 19:21:19
Also in: virtualization

On Mon, Sep 28, 2020 at 11:39:14AM +0800, xiangxia.m.yue@gmail.com wrote:
From: Tonghao Zhang <redacted>

Open vSwitch and Linux bridge will disable LRO of the interface
when this interface added to them. Now when disable the LRO, the
virtio-net csum is disable too. That drops the forwarding performance.

Fixes: e59ff2c49ae1 ("virtio-net: disable guest csum during XDP set")
I am a bit confused by this tag. Did this change bring about
disabling checksum when LRO is disabled? I am not sure
I follow how ...
quoted hunk ↗ jump to hunk
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Tonghao Zhang <redacted>
---
 drivers/net/virtio_net.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7145c83c6c8c..21b71148c532 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -63,6 +63,11 @@ static const unsigned long guest_offloads[] = {
 	VIRTIO_NET_F_GUEST_CSUM
 };
 
+#define GUEST_OFFLOAD_LRO_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
+				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
+				(1ULL << VIRTIO_NET_F_GUEST_ECN)  | \
+				(1ULL << VIRTIO_NET_F_GUEST_UFO))
+
 struct virtnet_stat_desc {
 	char desc[ETH_GSTRING_LEN];
 	size_t offset;
@@ -2531,7 +2536,8 @@ static int virtnet_set_features(struct net_device *dev,
 		if (features & NETIF_F_LRO)
 			offloads = vi->guest_offloads_capable;
 		else
-			offloads = 0;
+			offloads = vi->guest_offloads_capable &
+				   ~GUEST_OFFLOAD_LRO_MASK;
 
 		err = virtnet_set_guest_offloads(vi, offloads);
 		if (err)
-- 
2.23.0
  
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