[PATCH 3.13.y-ckt 049/122] xen/console: Update console event channel on resume

[Kamal Mostafa]

3.13.11-ckt22 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

commit b9d934f27c91b878c4b2e64299d6e419a4022f8d upstream.

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

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/tty/hvc/hvc_xen.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 636c9ba..856d971 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)
-- 
1.9.1

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