drm/xe/irq: Ensure primary GuC won't clobber media GuC's interrupt mask

Although primary and media GuC share a single interrupt enable bit, they
each have distinct bits in the mask register.  Although we always enable
interrupts for the primary GuC before the media GuC today (and never
disable either of them), this might not always be the case in the
future, so use a RMW when updating the mask register to ensure the other
GuC's mask doesn't get clobbered.
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230601215244.678611-24-matthew.d.roper@intel.comSigned-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_guc.c

@@ -532,12 +532,15 @@ static void guc_enable_irq(struct xe_guc *guc)
 		REG_FIELD_PREP(ENGINE0_MASK, GUC_INTR_GUC2HOST)  :
 		REG_FIELD_PREP(ENGINE1_MASK, GUC_INTR_GUC2HOST);
 
+	/* Primary GuC and media GuC share a single enable bit */
 	xe_mmio_write32(gt, GUC_SG_INTR_ENABLE,
 			REG_FIELD_PREP(ENGINE1_MASK, GUC_INTR_GUC2HOST));
-	if (xe_gt_is_media_type(gt))
+
+	/*
+	 * There are separate mask bits for primary and media GuCs, so use
+	 * a RMW operation to avoid clobbering the other GuC's setting.
+	 */
 	xe_mmio_rmw32(gt, GUC_SG_INTR_MASK, events, 0);
-	else
-		xe_mmio_write32(gt, GUC_SG_INTR_MASK, ~events);
 }
 
 int xe_guc_enable_communication(struct xe_guc *guc)