On Wed, 2011-05-18 at 10:00 -0700, Shirley Ma wrote: > On Wed, 2011-05-18 at 19:51 +0300, Michael S. Tsirkin wrote: > > > > Yes, I agree. I think for tcpdump, we really need to copy the > > data > > > > anyway, to avoid guest changing it in between. So we do that > and > > then > > > > use the copy everywhere, release the old one. Hmm? > > > > > > Yes. Old one use zerocopy, new one use copy data. > > > > > > Thanks > > > Shirley > > > > No, that's wrong, as they might become different with a > > malicious guest. As long as we copied already, lets realease > > the data and have everyone use the copy. > > Ok, I will patch pskb_expand_head to test it out. I am patching skb_copy, skb_clone, pskb_copy, pskb_expand_head to convert a zero-copy skb to a copy skb to avoid this kind of issue. This overhead won't impact macvtap/vhost TX zero-copy normally. Shirley -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
