diff --git a/src/main/scala/coreplex/Coreplex.scala b/src/main/scala/coreplex/Coreplex.scala
index 7ec15395..8599205e 100644
--- a/src/main/scala/coreplex/Coreplex.scala
+++ b/src/main/scala/coreplex/Coreplex.scala
@@ -193,7 +193,9 @@ class DefaultOuterMemorySystem(implicit p: Parameters) extends OuterMemorySystem
     case InnerTLId => "L1toL2"
     case OuterTLId => "L2toMMIO"
   })))
-  io.mmio <> mmioManager.io.outer
+
+  io.mmio.acquire <> Queue(mmioManager.io.outer.acquire, 1)
+  mmioManager.io.outer.grant <> Queue(io.mmio.grant, 1)
 
   // Wire the tiles to the TileLink client ports of the L1toL2 network,
   // and coherence manager(s) to the other side
diff --git a/vsim/Makefrag b/vsim/Makefrag
index 0461ef5f..a2e3e5db 100644
--- a/vsim/Makefrag
+++ b/vsim/Makefrag
@@ -45,7 +45,7 @@ VCS_OPTS = -notice -line +lint=all,noVCDE,noONGS,noUI -error=PCWM-L -timescale=1
 	$(RISCV)/lib/libfesvr.so \
 	-sverilog \
 	+incdir+$(generated_dir) \
-	+define+CLOCK_PERIOD=0.5 $(sim_vsrcs) $(sim_csrcs) \
+	+define+CLOCK_PERIOD=1.0 $(sim_vsrcs) $(sim_csrcs) \
 	+define+PRINTF_COND=$(TB).printf_cond \
 	+define+STOP_COND=!$(TB).reset \
 	+define+RANDOMIZE \
diff --git a/vsrc/TestDriver.v b/vsrc/TestDriver.v
index f188c96e..4d5bd632 100644
--- a/vsrc/TestDriver.v
+++ b/vsrc/TestDriver.v
@@ -5,7 +5,7 @@ module TestDriver;
   reg clk   = 1'b0;
   reg reset = 1'b1;
 
-  always #`CLOCK_PERIOD clk = ~clk;
+  always #(`CLOCK_PERIOD/2.0) clk = ~clk;
   initial #777.7 reset = 0;
 
   // Read input arguments and initialize
@@ -39,12 +39,25 @@ module TestDriver;
 `endif
   end
 
+`ifdef TESTBENCH_IN_UVM
+  // UVM library has its own way to manage end-of-simulation.
+  // A UVM-based testbench will raise an objection, watch this signal until this goes 1, then drop the objection.
+  reg finish_request = 1'b0;
+`endif
   reg [255:0] reason = "";
   reg failure = 1'b0;
   wire success;
   integer stderr = 32'h80000002;
   always @(posedge clk)
   begin
+`ifdef GATE_LEVEL
+    if (verbose)
+    begin
+      $fdisplay(stderr, "C: %10d", trace_count);
+    end
+`endif
+
+    trace_count = trace_count + 1;
     if (!reset)
     begin
       if (max_cycles > 0 && trace_count > max_cycles)
@@ -65,22 +78,15 @@ module TestDriver;
         if (verbose)
           $fdisplay(stderr, "Completed after %d simulation cycles", trace_count);
         `VCDPLUSCLOSE
+`ifdef TESTBENCH_IN_UVM
+        finish_request = 1;
+`else
         $finish;
+`endif
       end
     end
   end
 
-  always @(posedge clk)
-  begin
-    trace_count = trace_count + 1;
-`ifdef GATE_LEVEL
-    if (verbose)
-    begin
-      $fdisplay(stderr, "C: %10d", trace_count-1);
-    end
-`endif
-  end
-
   TestHarness testHarness(
     .clk(clk),
     .reset(reset),