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Date: Mon, 08 Sep 2014 16:17:46 -0700
From: Peter Grehan <grehan@freebsd.org>
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To: Nikolay Denev <ndenev@gmail.com>
Subject: Re: Bhyve virtio-net indirect descriptors
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Hi Nikolay,

> Any reason why bhyve is not advertising indirect descriptors for virtio-net?

  Indirect descriptors never seemed to make a lot of sense to me for 
networking. It requires allocations at the end of the transmit path 
which could potentially fail, or requires large amounts of preallocation 
to deal with maximum-sized segments. So, the initial version of bhyve's 
virtio-net didn't support it since I felt it impacted guest drivers.

  However, with Chris Torek's contribution of virtio.c, the additional 
work of dealing with the descriptors is hidden in the virtio api. For 
transmit it should just work, but there has to be some extra code added 
for receive.

  Did you have any particular guests in mind ?

later,

Peter.