* NOTE: in this case, the hvsock channel is an exception, because
* it looks the host side's hvsock implementation has a throttling
* mechanism which can hurt the performance otherwise.
+ *
+ * KYS: Oct. 30, 2016:
+ * It looks like Windows hosts have logic to deal with DOS attacks that
+ * can be triggered if it receives interrupts when it is not expecting
+ * the interrupt. The host expects interrupts only when the ring
+ * transitions from empty to non-empty (or full to non full on the guest
+ * to host ring).
+ * So, base the signaling decision solely on the ring state until the
+ * host logic is fixed.
*/
- if (((ret == 0) && kick_q && signal) ||
- (ret && !is_hvsock_channel(channel)))
+ if (((ret == 0) && signal))
vmbus_setevent(channel);
return ret;
* If we cannot write to the ring-buffer; signal the host
* even if we may not have written anything. This is a rare
* enough condition that it should not matter.
+ *
+ * KYS: Oct. 30, 2016:
+ * It looks like Windows hosts have logic to deal with DOS attacks that
+ * can be triggered if it receives interrupts when it is not expecting
+ * the interrupt. The host expects interrupts only when the ring
+ * transitions from empty to non-empty (or full to non full on the guest
+ * to host ring).
+ * So, base the signaling decision solely on the ring state until the
+ * host logic is fixed.
*/
- if (((ret == 0) && kick_q && signal) || (ret))
+ if (((ret == 0) && signal))
vmbus_setevent(channel);
return ret;
}
dev_type = hv_get_dev_type(newchannel);
- if (dev_type == HV_NIC)
- set_channel_signal_state(newchannel, HV_SIGNAL_POLICY_EXPLICIT);
init_vp_index(newchannel, dev_type);
if (READ_ONCE(rbi->ring_buffer->interrupt_mask))
return false;
- /*
- * When the client wants to control signaling,
- * we only honour the host interrupt mask.
- */
- if (policy == HV_SIGNAL_POLICY_EXPLICIT)
- return true;
-
/* check interrupt_mask before read_index */
virt_rmb();
/*