xen/console: Update console event channel on resume

After a resume the hypervisor/tools may change console event
channel number. We should re-query it.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index f1e57425e39f..5bab1c684bb1 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -299,11 +299,27 @@ static int xen_initial_domain_console_init(void)
         return 0;
 }
 
+static void xen_console_update_evtchn(struct xencons_info *info)
+{
+        if (xen_hvm_domain()) {
+                uint64_t v;
+                int err;
+
+                err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+                if (!err && v)
+                        info->evtchn = v;
+        } else
+                info->evtchn = xen_start_info->console.domU.evtchn;
+}
+
 void xen_console_resume(void)
 {
         struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
-        if (info != NULL && info->irq)
+        if (info != NULL && info->irq) {
+                if (!xen_initial_domain())
+                        xen_console_update_evtchn(info);
                 rebind_evtchn_irq(info->evtchn, info->irq);
+        }
 }
 
 static void xencons_disconnect_backend(struct xencons_info *info)