xen-bus: use a separate fd for each event channel

To better support use of IOThread-s it will be necessary to be able to set
the AioContext for each XenEventChannel and hence it is necessary to open a
separate handle to libxenevtchan for each channel.

This patch stops using NotifierList for event channel callbacks, replacing
that construct by a list of complete XenEventChannel structures. Each of
these now has a xenevtchn_handle pointer in place of the single pointer
previously held in the XenDevice structure. The individual handles are
opened/closed in xen_device_bind/unbind_event_channel(), replacing the
single open/close in xen_device_realize/unrealize().

NOTE: This patch does not add an AioContext parameter to
      xen_device_bind_event_channel(). That will be done in a subsequent
      patch.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Message-Id: <20190408151617.13025-2-paul.durrant@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h
index 3183f10e3c..3315f0de20 100644
--- a/include/hw/xen/xen-bus.h
+++ b/include/hw/xen/xen-bus.h
@@ -15,6 +15,7 @@
 typedef void (*XenWatchHandler)(void *opaque);
 
 typedef struct XenWatch XenWatch;
+typedef struct XenEventChannel XenEventChannel;
 
 typedef struct XenDevice {
     DeviceState qdev;
@@ -28,8 +29,7 @@ typedef struct XenDevice {
     XenWatch *backend_online_watch;
     xengnttab_handle *xgth;
     bool feature_grant_copy;
-    xenevtchn_handle *xeh;
-    NotifierList event_notifiers;
+    QLIST_HEAD(, XenEventChannel) event_channels;
 } XenDevice;
 
 typedef char *(*XenDeviceGetName)(XenDevice *xendev, Error **errp);
@@ -119,8 +119,6 @@ void xen_device_copy_grant_refs(XenDevice *xendev, bool to_domain,
                                 XenDeviceGrantCopySegment segs[],
                                 unsigned int nr_segs, Error **errp);
 
-typedef struct XenEventChannel XenEventChannel;
-
 typedef void (*XenEventHandler)(void *opaque);
 
 XenEventChannel *xen_device_bind_event_channel(XenDevice *xendev,