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Xin Zhao

2005-Jan-17 21:57 UTC

[Xen-devel] weird problem in event channel setup

Hi, folks,

I ran into a weird problem when I tried to setup an event channel between
dom0 and domU:

My code is quite simple: first, a dom0 application create a new channel
and bind dom0 and domU with this channel, second, the dom0 send a message
over control interface and send a notification via the control channel to the
domU,
then the dom0 application quited.

At the domU side, I used a kernel module to listen on the message by
calling ctrl_if_register_receiver, when a message is available, the kernel
module will print out the message.

When I run the dom0 app for a couple of times in a fast manner, domU will
be suspended. But if I run the dom0 application in a slow way (run, wait
for a while, run again), domU works fine.

Anybody knows why? Please give me hand. Thanks.

-X


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Anthony Liguori

2005-Jan-17 23:13 UTC

head link

Re: [Xen-devel] weird problem in event channel setup

---- Original message ---->Date: Mon, 17 Jan 2005 16:57:53 -0500 (EST)
>From: Xin Zhao <zhaoxin@eecs.umich.edu>  
>Subject: [Xen-devel] weird problem in event channel setup  
>To: xen-devel@lists.sourceforge.net
>
>Hi, folks,
>
>I ran into a weird problem when I tried to setup an event channel between
>dom0 and domU:
Using which ports?
>My code is quite simple: first, a dom0 application create a new channel
>and bind dom0 and domU with this channel, second, the dom0 send a message
>over control interface and send a notification via the control channel
to the domU,>then the dom0 application quited.
Where you using the control_msg_t ring queues?  If so, what did you base
your code on?
>At the domU side, I used a kernel module to listen on the message by
>calling ctrl_if_register_receiver, when a message is available, the kernel
>module will print out the message.
>
>When I run the dom0 app for a couple of times in a fast manner, domU will
>be suspended. But if I run the dom0 application in a slow way (run, wait
>for a while, run again), domU works fine.
Maybe the queue is filling up and you''re not gracefully handling it. 
Hard to say, would it be possible to post your code somewhere?

Regards,

Anthony Liguori
email: aliguori@us.ibm.com
>Anybody knows why? Please give me hand. Thanks.
>
>-X
>
>
>-------------------------------------------------------
>The SF.Net email is sponsored by: Beat the post-holiday blues
>Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek.
>It''s fun and FREE -- well,
almost....http://www.thinkgeek.com/sfshirt
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@lists.sourceforge.net
>https://lists.sourceforge.net/lists/listinfo/xen-devel

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Xin Zhao

2005-Jan-18 15:59 UTC

head link

Re: [Xen-devel] weird problem in event channel setup

The pseudo code is like this:

At the Dom0 side:

1. xu_port_new(domid,0,0)  // create a new port and connect dom0 and
domU(domid)

2. create a new message

    ctrl_msg_t cmsg;
    cmsg.type      = CMSG_SVDIF_FE;
    cmsg.id  = 1;
    cmsg.subtype   = 1;

    channel_msg.local = scp->local_port;
    channel_msg.remote = scp->remote_port;
    memcpy(cmsg.msg,&channel_msg,sizeof(channel_msg));
    cmsg.length    = sizeof(channel_msg);

3. xu_port_write_request() send out the new msg

4. xu_port_notify() send out notification to the DomU, the local port is
retrieved with the following codes:

local_port = 0;
remote_port = 1;
xc_evtchn_bind_interdomain(self->xc_handle,DOMID_SELF,domid,&local_port,
&remote_port);

5. quit.

At the DomU side, we use a simple kernel module, it first register a
receiver with ctrl_if_register_receiver(CMSG_SVDIF_FE, ctrl_if_rx);
In ctrl_if_rx, we just print out the received msg.

That''s it. If the Dom0 app runs in a slow manner, everything seems to
be
fine. But if the Dom0 app runs very fast, after 2 or 3 rounds, DomU will
suspend.

Can someone help me out? I was stuck for quite long time. :( Thanks in
advance.

Xin

On Mon, 17 Jan 2005, Anthony Liguori wrote:
> ---- Original message ----
> >Date: Mon, 17 Jan 2005 16:57:53 -0500 (EST)
> >From: Xin Zhao <zhaoxin@eecs.umich.edu>
> >Subject: [Xen-devel] weird problem in event channel setup
> >To: xen-devel@lists.sourceforge.net
> >
> >Hi, folks,
> >
> >I ran into a weird problem when I tried to setup an event channel
between
> >dom0 and domU:
>
> Using which ports?
>
> >My code is quite simple: first, a dom0 application create a new channel
> >and bind dom0 and domU with this channel, second, the dom0 send a
message
> >over control interface and send a notification via the control channel
> to the domU,
> >then the dom0 application quited.
>
> Where you using the control_msg_t ring queues?  If so, what did you base
> your code on?
>
> >At the domU side, I used a kernel module to listen on the message by
> >calling ctrl_if_register_receiver, when a message is available, the
kernel
> >module will print out the message.
> >
> >When I run the dom0 app for a couple of times in a fast manner, domU
will
> >be suspended. But if I run the dom0 application in a slow way (run,
wait
> >for a while, run again), domU works fine.
>
> Maybe the queue is filling up and you''re not gracefully handling
it.
> Hard to say, would it be possible to post your code somewhere?
>
> Regards,
>
> Anthony Liguori
> email: aliguori@us.ibm.com
>
> >Anybody knows why? Please give me hand. Thanks.
> >
> >-X
> >
> >
> >-------------------------------------------------------
> >The SF.Net email is sponsored by: Beat the post-holiday blues
> >Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek.
> >It''s fun and FREE -- well,
almost....http://www.thinkgeek.com/sfshirt
> >_______________________________________________
> >Xen-devel mailing list
> >Xen-devel@lists.sourceforge.net
> >https://lists.sourceforge.net/lists/listinfo/xen-devel
>

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Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek.
It''s fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt
_______________________________________________
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Xen devel - Jan 2005 - weird problem in event channel setup

[Xen-devel] weird problem in event channel setup

Re: [Xen-devel] weird problem in event channel setup

Re: [Xen-devel] weird problem in event channel setup