[Bug 638955] Re: [Qemu-devel] [PATCH] e1000: Pad short frames to minimum size (60 bytes)

[Anthony Liguori <anthony@codemonkey.ws>]

On 09/20/2010 03:44 PM, Michael S. Tsirkin wrote:
>>>  From f77c3143f3fbefdfa2f0cc873c2665b5aa78e8c9 Mon Sep 17 00:00:00 2001
>>> From: Anthony Liguori<aliguori@us.ibm.com>
>>> Date: Mon, 20 Sep 2010 15:29:31 -0500
>>> Subject: [PATCH] tap: make sure packets are at least 40 bytes long
>>>
>>> This is required by ethernet drivers but not enforced in the Linux tap code so
>>> we need to fix it up ourselves.
>>>        
>>
>> This enforces ethernet semantics on the internal links (which is probably
>> not good),
>>      
> Plus plus ungood.
> When we do add e.g. ipoib support, we'll have to go and hunt these bugs down again.
> Also will make it impossible to implement any devices that pass in guest buffers
> without FCS and padding.
>    

That's actually a good point which strongly is in favor of making the 
devices do the padding themselves.

Regards,

Anthony Liguori

-- 
emulated netcards don't work with recent sunos kernel
https://bugs.launchpad.net/bugs/638955
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Status in QEMU: New

Bug description:
hi there,

i'm using qemu-kvm backend in version: # qemu-kvm -version
QEMU PC emulator version 0.12.5 (qemu-kvm-0.12.5), Copyright (c) 2003-2008 Fabrice Bellard

and there are just *not working any of model=$type with combinations of recent sunos (solaris, openindiana, opensolaris, ..) ..

you can download for testing purposes iso from here: http://dlc-origin.openindiana.org/isos/147/ or from here: http://genunix.org/distributions/indiana/ << osol and oi are also bubuntu-like *live cds, so no need to bother with installing

behaviour is as follows:
e1000 - receiving doesn't work, transmitting works .. dladm (tool for handle ethers) shows that is all ok, correct mode is loaded up, it just seems like this driver works at 100% but ..

rtl8169|pcnet - works in 10Mbit mode with several other issues like high cpu utilization and so .. dladm is unable to recognize options for this kind of -nic

others - just don't work

.. i experienced this issue several times in past .. woraround was, that rtl8169 worked so-so .. with recent sunos kernel it doesn't.

it's easy to reproduce, this is why i'm not putting here more then launching script for my virtual machine:

# cat openindiana.sh
qemu-kvm -hda /home/kvm/openindiana/openindiana.img -m 2048 -localtime -cdrom /home/kvm/+images/oi-dev-147-x86.iso -boot d \
-vga std -vnc :9 -k en-us -monitor unix:/home/kvm/openindiana/instance,server,nowait \
-net nic,model=e1000,vlan=1 -net tap,ifname=oi0,script=no,vlan=1 &

sleep 2;
ip l set oi0 up;
ip a a 192.168.99.9/24 dev oi0;

regards by daniel