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Date: Sun, 19 May 2013 15:19:42 +0200
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Subject: Re: [Qemu-devel] Writing a CAN driver for QEMU
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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>, "Rempel,
	Cynthia" <cynt6007@vandals.uidaho.edu>, "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 19/05/2013 14:58, Paolo Bonzini ha scritto:
> 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.
> 
> 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).

Ok, learnt a bit more...  You could probably implement this in two ways:
1) "-netdev socket" would probably work as a CAN->UDP gateway; 2)
connecting to a virtual CAN interface in the host, created using
SocketCAN (similar to "-netdev tap", e.g. "-netdev cantap").

In the first case, it would probably be useful to write the matching
UDP->CAN gateway program.

In any case, you have to implement both the backend and the actual device.

Paolo