From: Anthony Liguori <aliguori@linux.vnet.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Shirley Ma <mashirle@us.ibm.com>,
Rusty Russell <rusty@rustcorp.com.au>,
qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: [PATCH] qemu/virtio-net: remove wrong s/g layout assumptions
Date: Tue, 24 Nov 2009 13:50:25 -0600 [thread overview]
Message-ID: <4B0C3901.5010100@linux.vnet.ibm.com> (raw)
In-Reply-To: <20091124194502.GA4250@redhat.com>
Michael S. Tsirkin wrote:
> virtio net currently assumes that the first s/g element it gets is
> always virtio net header. This is wrong.
> There should be no assumption on sg boundaries. For example, the guest
> should be able to put the virtio_net_hdr in the front of the skbuf data
> if there is room. Get rid of this assumption, properly consume space
> from iovec, always.
>
Practically speaking, we ought to advertise a feature bit to let a
kernel know that we are no longer broken.
Otherwise, there are a ton of old userspaces that will break with new
guests.
--
Regards,
Anthony Liguori
next prev parent reply other threads:[~2009-11-24 19:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-24 19:45 [Qemu-devel] [PATCH] qemu/virtio-net: remove wrong s/g layout assumptions Michael S. Tsirkin
2009-11-24 19:50 ` Anthony Liguori [this message]
2009-11-24 19:54 ` [Qemu-devel] " Michael S. Tsirkin
2009-11-24 21:04 ` Anthony Liguori
2009-11-24 21:30 ` Michael S. Tsirkin
2009-11-24 21:57 ` Anthony Liguori
2009-11-24 22:20 ` Michael S. Tsirkin
2009-11-30 11:16 ` Michael S. Tsirkin
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