From e53f9cb74c7f82f5de2e115cf3e53b853cb07812 Mon Sep 17 00:00:00 2001
From: Tilmann Bartsch <info@tebartsch.ai>
Date: Mon, 22 Jan 2024 23:18:36 +0100
Subject: [PATCH] PLIC: Implement threshold masking

Signed-off-by: Tilmann Bartsch <info@tebartsch.ai>
---
 riscv/plic.cc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/riscv/plic.cc b/riscv/plic.cc
index 44f80cf9..01def705 100644
--- a/riscv/plic.cc
+++ b/riscv/plic.cc
@@ -113,6 +113,15 @@ uint32_t plic_t::context_best_pending(const plic_context_t *c)
     }
   }
 
+  /*
+  From Spec 1.0.0: 6. Priority Thresholds
+  The PLIC will mask all PLIC interrupts of a priority less than or equal to
+  threshold.
+  */
+  if (best_id_prio <= c->priority_threshold) {
+    return 0;
+  }
+
   return best_id;
 }