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Diffstat (limited to 'drivers/hv/hyperv_vmbus.h')
-rw-r--r--drivers/hv/hyperv_vmbus.h24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index b0299da9c2db..cada56a2daa0 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -624,6 +624,30 @@ struct vmbus_channel_message_table_entry {
extern struct vmbus_channel_message_table_entry
channel_message_table[CHANNELMSG_COUNT];
+/* Free the message slot and signal end-of-message if required */
+static inline void vmbus_signal_eom(struct hv_message *msg)
+{
+ msg->header.message_type = HVMSG_NONE;
+
+ /*
+ * Make sure the write to MessageType (ie set to
+ * HVMSG_NONE) happens before we read the
+ * MessagePending and EOMing. Otherwise, the EOMing
+ * will not deliver any more messages since there is
+ * no empty slot
+ */
+ mb();
+
+ if (msg->header.message_flags.msg_pending) {
+ /*
+ * This will cause message queue rescan to
+ * possibly deliver another msg from the
+ * hypervisor
+ */
+ wrmsrl(HV_X64_MSR_EOM, 0);
+ }
+}
+
/* General vmbus interface */
struct hv_device *vmbus_device_create(const uuid_le *type,