xive: Don't mess around with the ESB state when setting an IRQ config

The host code needs to manage the ESB state in specific ways, it's not
correct to blindly unmask the source when targetting for example, so
let's not do that, the host will do it itself when appropriate.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

hw/xive.c

@@ -3403,7 +3403,16 @@ static int64_t opal_xive_set_irq_config(uint32_t girq,
 	int64_t rc;
 
 	/*
-	 * WARNING: See comment in set_xive()
+	 * This variant is meant for a XIVE-aware OS, thus it will
+	 * *not* affect the ESB state of the interrupt. If used with
+	 * a prio of FF, the IVT/EAS will be mased. In that case the
+	 * races have to be handled by the OS.
+	 *
+	 * The exception to this rule is interrupts for which masking
+	 * and unmasking is handled by firmware. In that case the ESB
+	 * state isn't under OS control and will be dealt here. This
+	 * is currently only the case of LSIs and on P9 DD1.0 only so
+	 * isn't an issue.
 	 */
 
 	if (xive_mode != XIVE_MODE_EXPL)
@@ -3427,9 +3436,6 @@ static int64_t opal_xive_set_irq_config(uint32_t girq,
 		 * is handled by the XIVE
 		 */
 		rc = s->orig_ops->set_xive(is, girq, 0, prio);
-	} else {
-		/* Ensure it's enabled/disabled in the source controller */
-		xive_update_irq_mask(s, girq - s->esb_base, prio == 0xff);
 	}
 
 	/*