>From: Michael S. Tsirkin [mailto:mst@xxxxxxxxxx] >Sent: Monday, September 27, 2010 1:02 AM >To: Xin, Xiaohui >Cc: netdev@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >mingo@xxxxxxx; davem@xxxxxxxxxxxxx; herbert@xxxxxxxxxxxxxxxxxxxx; >jdike@xxxxxxxxxxxxxxx >Subject: Re: [PATCH v11 00/17] Provide a zero-copy method on KVM virtio-net. > >On Sat, Sep 25, 2010 at 12:27:18PM +0800, xiaohui.xin@xxxxxxxxx wrote: >> We provide an zero-copy method which driver side may get external >> buffers to DMA. Here external means driver don't use kernel space >> to allocate skb buffers. Currently the external buffer can be from >> guest virtio-net driver. >> >> The idea is simple, just to pin the guest VM user space and then >> let host NIC driver has the chance to directly DMA to it. >> The patches are based on vhost-net backend driver. We add a device >> which provides proto_ops as sendmsg/recvmsg to vhost-net to >> send/recv directly to/from the NIC driver. KVM guest who use the >> vhost-net backend may bind any ethX interface in the host side to >> get copyless data transfer thru guest virtio-net frontend. >> patch 01-10: net core and kernel changes. >> patch 11-13: new device as interface to mantpulate external buffers. >> patch 14: for vhost-net. >> patch 15: An example on modifying NIC driver to using napi_gro_frags(). >> patch 16: An example how to get guest buffers based on driver >> who using napi_gro_frags(). >> patch 17: It's a patch to address comments from Michael S. Thirkin >> to add 2 new ioctls in mp device. >> We split it out here to make easier reiewer. > > > >I commented on how to avoid mm semaphore on data path separately, and >since you didn't have time to review that yet, I won't repeat that here. > I think I did avoid that in data path to use mm semaphore. I stored the value in mp structures and check with that. >At this point what are the plans on macvtap integration? >You indicated this is the interface you intend to use longterm. I'm now working on that. Thanks Xiaohui -- 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
