CVS commit: src/sys/arch/xen/xen

["Cherry G. Mathew" <cherry%netbsd.org@localhost>]

Module Name:    src
Committed By:   cherry
Date:           Sun Nov 25 07:48:47 UTC 2012

Modified Files:
        src/sys/arch/xen/xen: evtchn.c

Log Message:
hypervisor_set_ipending() should not set the pending flag across cpus. The 
reason for this is that the pending flag update is not atomic, or protected by 
a lock. Since its current (mis)use in evtchn_do_event() across cpus is to 
notify the remote cpu of an interrupt, we use hypervisor_send_event() instead, 
to trigger an event on the remote cpu, which in turn invokes evtchn_do_event() 
on that cpu and DTRT on it.

On the local cpu, we protect hypervisor_set_ipending() from re-entry via cli(). 
Remove a redundant and unprotected call to hypervisor_set_ipending().

Thanks to jym@ for spotting this discrepancy while reviewing a related patch.

See: http://mail-index.netbsd.org/tech-kern/2012/11/12/msg014374.html


To generate a diff of this commit:
cvs rdiff -u -r1.62 -r1.63 src/sys/arch/xen/xen/evtchn.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.