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Date: Sun, 19 May 2013 14:58:48 +0200
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Subject: Re: [Qemu-devel] Writing a CAN driver for QEMU
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To: "Rempel, Cynthia" <cynt6007@vandals.uidaho.edu>
Cc: Gedare Bloom <gedare@rtems.org>, Amar Takhar <verm@darkbeer.org>, Petr Benes <petben@petben.net>, Thomas Doerfler <Thomas.Doerfler@embedded-brains.de>, "Sebastian.Huber@embedded-brains.de" <Sebastian.Huber@embedded-brains.de>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Jennifer Averett <Jennifer.Averett@oarcorp.com>, Chris Johns <chrisj@rtems.org>, Cl?udio Silva <claudiodcsilva@gmail.com>, Joel Sherrill <joel.sherrill@oarcorp.com>, Pavel Pisa <pisa@cmp.felk.cvut.cz>

Il 18/05/2013 20:24, Rempel, Cynthia ha scritto:
> we want to be able to verify a guest OS's CAN driver has been integrated properly and is sending CAN packets... 
> 
> Perhaps along the lines of two calls:
> qemu-system-arm -hda linux1.img -can student-implemented-device
> qemu-system-arm -hda linux2.img -can student-implemented-device

You would probably use either -net, or -netdev and -device (see
docs/qdev-device-use.txt).

> Then using a network protocol analyzer (such as Wireshark) with a custom filter to recognize CAN packets,
> OR
> qemu-system-arm -hda linux1.img -can student-implemented-device
> then attaching a real CAN device to the host computer and verifying that the output is being recognized be real hardware.

Is this CAN device just an Ethernet device?  QEMU does not support other
link-level protocols.  Adding them would be possible and interesting,
however it would add a bit to the complexity.

> Whichever is more feasible to implement...

Both would be the same.  In the first case, you'd probably use "-netdev
socket" to share a virtual network between two virtual machines.  In the
second, you would use something like "-netdev tap" (again assuming it's
just an Ethernet device).

Paolo