error binding to event channel

error binding to event channel

[Jacob Gorm Hansen]

hi,
I am trying to bind an event channel to my domain using the following code:

#include "xc.h"

int main()
{
     int xc_handle = xc_interface_open();
     int p1=0;
     int p2=0;
     int r;

     r = xc_evtchn_alloc_unbound(xc_handle,
                             1,
                             &p2);
     printf("%d ports %d %d\n", r,p1,p2);

     r = xc_evtchn_bind_interdomain(xc_handle,
             DOMID_SELF,1,
             &p1,&p2);

     printf("%d ports %d %d\n", r,p1,p2);
     r = xc_evtchn_send(xc_handle, p1);
     printf("send %d\n", r);

     return 0;
}

On a freshly booted Xen with one domU that works, printing:

0 ports 0 14
0 ports 15 14
send 0

however, the next time I run it I get:

0 ports 0 16
-1 ports 0 16
send -1


The bind_interdomain hypercall fails in Xen in common/evtchn.c, in the test:

     else if ( port2 >= d2->max_event_channel )
     {
         printk("port2 %d max_event_channel %d\n", 
port2,d2->max_event_channel);
         ERROR_EXIT(-EINVAL);
     }

The printk I have added prints:

(XEN) port2 16 max_event_channel 16


-- In general, max_event_channel seems to stop being increased after the 
first bind call. What am I doing wrong here?

thanks,
Jacob


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Re: error binding to event channel

[Jacob Gorm Hansen]

Jacob Gorm Hansen wrote:
> hi,
> I am trying to bind an event channel to my domain using the following code:

OK I have it sorted now, using a constant port number at the domU end, 
the code looks like this:

         int p1=0;
         int p2=0;
         int r;

         p2=14;
         r = xc_evtchn_bind_interdomain(xc_handle,
                 DOMID_SELF,domu_dom_id,
                 &p1,&p2);

         r = xc_evtchn_send(xc_handle, p1);


and on the receiving end:

         int my_irq = bind_evtchn_to_irq(14);
         printk("bound irq %d\n", my_irq);

         int r = request_irq(my_irq, my_interrupt_handler, 
SA_SAMPLE_RANDOM, , "myirq", 0);

Jacob


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