I updated the vcpu_to_cpu string creation to include a field separator,

which gets rid of the -1 -> # hack and works for cpus > 9.

I ran into some issues with stale vcpu_to_cpu lists when running the
hotplug subprogram.  I would take a vcpu offline, and then issue the
command to bring it back and the vcpu_to_cpu list would not have changed
to indicate the the vcpu actually went down.  If I injected a xm list -v
(which always showed the correct mapping) then subsequent hotplug
commands would see the state change and fire off the hotplug request.  I
don't know that not sending the event when not changing state saves that
much work so I took the state check out and now just send the hotplug
event directly.

> Also the whole hotplug stuff is still missing interrupt re-routing
> when a vcpu is taken down.  To do this, we need an evtchn operation to
> change the vcpu affinity of a port by changing notify_vcpu_id.

I don't fully understand all of the mappings that are happening, so this
part of the patch might be way off.  In any case, I've added a new
evtchn op to set the notify_vcpu_id field of a channel.  I updated the
HOTPLUG_CPU code to use the new routines when bringing cpus up and down.
When taking down a cpu, I route the IPI irq channels to CPU 0, and when
the cpu comes up, it re-routes the channels back to the awakened CPU.

From: Ryan Harper <ryanh@us.ibm.com>
Signed-off-by: ian@xensource.com

1 files changed, 8 insertions, 0 deletions

diff --git a/xen/include/public/event_channel.h b/xen/include/public/event_channel.h
index 3110657b77..ceacf3fc34 100644
--- a/xen/include/public/event_channel.h
+++ b/xen/include/public/event_channel.h
@@ -158,6 +158,13 @@ typedef struct evtchn_status {
     } u;
 } evtchn_status_t;
 
+#define EVTCHNOP_rebind        8
+typedef struct {
+    /* IN parameters. */
+    u32 port;                         /*  0 */
+    u32 vcpu;                         /*  4 */
+} evtchn_rebind_t; /* 8 bytes */
+
 typedef struct evtchn_op {
     u32 cmd; /* EVTCHNOP_* */
     union {
@@ -169,6 +176,7 @@ typedef struct evtchn_op {
         evtchn_close_t            close;
         evtchn_send_t             send;
         evtchn_status_t           status;
+        evtchn_rebind_t           rebind;
     } u;
 } evtchn_op_t;