From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Warfield Subject: Re: console driver - How domain0 processes console messages ? Date: Wed, 16 Feb 2005 07:54:22 +0000 Message-ID: References: Reply-To: andrew.warfield@cl.cam.ac.uk Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit In-Reply-To: Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Richard Cc: xen-devel@lists.sourceforge.net List-Id: xen-devel@lists.xenproject.org > I am trying to undestand how domain0 processes console > messages (i.e messages with type CMSG_CONSOLE and subtype > CMSG_CONSOLE_DATA). Console messages currently share the same shared memory rings that control messages use. As such, ctrl_if_send_message_noblock(), is a non-blocking send on these rings, and ctrl_if_notify_controller() is an event channel notification of a control event. Aside from console messages, control messages are exactly that -- things like driver setup and connection. See xen/include/public/io/domain_controller.h for a full list. The control message rings are mapped to user space in dom0 through calls to libxc, while the notification is delivered to dom0 via /dev/evtchn. If you are using stable or testing, these rings are accessed directly by xend, see tools/python/xen/lowlevel/xu/xu.c (especially the notifier and port objects therein). If you are using the unstable tree, xcs (tools/xcs/xcs.c) demultiplexes the shared rings/event channels. In xend, consol messages are eventually handled in tools/python/xen/xend/server/console.py. Hope that helps. We plan to separate the console messages from the control rings in the very near future, allowing them to have a separate driver and be throttled independent of control messages. This should make the current interface considerably simpler. hth, a. ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click