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Date: Fri, 14 Feb 2014 14:41:24 +0100
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From: Vincenzo Maffione <v.maffione@gmail.com>
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Subject: Re: [Qemu-devel] net: Adding netmap network backend
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To: Luigi Rizzo <rizzo@iet.unipi.it>
Cc: Michael Tokarev <mjt@tls.msk.ru>, qemu-devel <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>

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Stefan,
  It is ok for you if I prepare a patch (touching configure and
net/netmap.c) that makes sure the host kernel has the minimum netmap
version required for QEMU to work (and if not just --disable-netmap)?

Cheers,
  Vincenzo


2014-02-14 11:24 GMT+01:00 Luigi Rizzo <rizzo@iet.unipi.it>:

>
>
>
> On Fri, Feb 14, 2014 at 2:20 AM, Vincenzo Maffione <v.maffione@gmail.com>wrote:
>
>> Yes, for sure we need to do a check.
>>
>> However, this would involve - I think - some non-trivial modifications to
>> net/netmap.c, because without NS_MOREFRAG you cannot split a packet over
>> more "netmap slots/descriptors" (both tx and rx side)
>>
>> Therefore I would ask (manly Luigi, since netmap is in-tree in FreeBSD):
>> Wouldn't it be better to force --disable-netmap when we realize that
>> NETMAP_API (version number for the netmap API) is less than the value
>> required by QEMU? This can be done in ./configure. In this way we keep the
>> QEMU code cleaner.
>>
>
> yes we should do exactly what vincenzo suggests.
>
> cheers
> luigi
>



-- 
Vincenzo Maffione

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<div dir=3D"ltr"><div><div><div>Stefan,<br></div>=A0 It is ok for you if I =
prepare a patch (touching configure and net/netmap.c) that makes sure the h=
ost kernel has the minimum netmap version required for QEMU to work (and if=
 not just --disable-netmap)?<br>
<br></div>Cheers,<br></div>=A0 Vincenzo<br></div><div class=3D"gmail_extra"=
><br><br><div class=3D"gmail_quote">2014-02-14 11:24 GMT+01:00 Luigi Rizzo =
<span dir=3D"ltr">&lt;<a href=3D"mailto:rizzo@iet.unipi.it" target=3D"_blan=
k">rizzo@iet.unipi.it</a>&gt;</span>:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div dir=3D"ltr"><div class=3D"gmail_default=
" style=3D"font-family:courier new,monospace"><br></div><div class=3D"gmail=
_extra">
<br><br><div class=3D"gmail_quote"><div class=3D"">On Fri, Feb 14, 2014 at =
2:20 AM, Vincenzo Maffione <span dir=3D"ltr">&lt;<a href=3D"mailto:v.maffio=
ne@gmail.com" target=3D"_blank">v.maffione@gmail.com</a>&gt;</span> wrote:<=
br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div dir=3D"ltr"><div><div><div>Yes, for sur=
e we need to do a check.<br><br>However, this would involve - I think - som=
e non-trivial modifications to net/netmap.c, because without NS_MOREFRAG yo=
u cannot split a packet over more &quot;netmap slots/descriptors&quot; (bot=
h tx and rx side)<br>



<br></div>Therefore I would ask (manly Luigi, since netmap is in-tree in Fr=
eeBSD): Wouldn&#39;t it be better to force --disable-netmap when we realize=
 that NETMAP_API (version number for the netmap API) is less than the value=
 required by QEMU? This can be done in ./configure. In this way we keep the=
 QEMU code cleaner.<br>

</div></div></div></blockquote><div><br></div></div><div class=3D"gmail_def=
ault" style=3D"font-family:&#39;courier new&#39;,monospace">yes we should d=
o exactly what vincenzo suggests.</div><div class=3D"gmail_default" style=
=3D"font-family:&#39;courier new&#39;,monospace">

<br></div><div class=3D"gmail_default" style=3D"font-family:&#39;courier ne=
w&#39;,monospace">cheers</div><span class=3D"HOEnZb"><font color=3D"#888888=
"><div class=3D"gmail_default" style=3D"font-family:&#39;courier new&#39;,m=
onospace">
luigi</div></font></span></div>
</div></div>
</blockquote></div><br><br clear=3D"all"><br>-- <br>Vincenzo Maffione<br>
</div>

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