diff --git a/hw/acpi/tco.c b/hw/acpi/tco.c
index 4783721e4e..9ebd3e5e64 100644
--- a/hw/acpi/tco.c
+++ b/hw/acpi/tco.c
@@ -86,6 +86,7 @@ static inline int can_start_tco_timer(TCOIORegs *tr)
 static uint32_t tco_ioport_readw(TCOIORegs *tr, uint32_t addr)
 {
     uint16_t rld;
+    uint32_t ret = 0;
 
     switch (addr) {
     case TCO_RLD:
@@ -96,35 +97,49 @@ static uint32_t tco_ioport_readw(TCOIORegs *tr, uint32_t addr)
         } else {
             rld = tr->tco.rld;
         }
-        return rld;
+        ret = rld;
+        break;
     case TCO_DAT_IN:
-        return tr->tco.din;
+        ret = tr->tco.din;
+        break;
     case TCO_DAT_OUT:
-        return tr->tco.dout;
+        ret = tr->tco.dout;
+        break;
     case TCO1_STS:
-        return tr->tco.sts1;
+        ret = tr->tco.sts1;
+        break;
     case TCO2_STS:
-        return tr->tco.sts2;
+        ret = tr->tco.sts2;
+        break;
     case TCO1_CNT:
-        return tr->tco.cnt1;
+        ret = tr->tco.cnt1;
+        break;
     case TCO2_CNT:
-        return tr->tco.cnt2;
+        ret = tr->tco.cnt2;
+        break;
     case TCO_MESSAGE1:
-        return tr->tco.msg1;
+        ret = tr->tco.msg1;
+        break;
     case TCO_MESSAGE2:
-        return tr->tco.msg2;
+        ret = tr->tco.msg2;
+        break;
     case TCO_WDCNT:
-        return tr->tco.wdcnt;
+        ret = tr->tco.wdcnt;
+        break;
     case TCO_TMR:
-        return tr->tco.tmr;
+        ret = tr->tco.tmr;
+        break;
     case SW_IRQ_GEN:
-        return tr->sw_irq_gen;
+        ret = tr->sw_irq_gen;
+        break;
     }
-    return 0;
+    trace_tco_io_read(addr, ret);
+    return ret;
 }
 
 static void tco_ioport_writew(TCOIORegs *tr, uint32_t addr, uint32_t val)
 {
+    trace_tco_io_write(addr, val);
     switch (addr) {
     case TCO_RLD:
         tr->timeouts_no = 0;
diff --git a/hw/acpi/trace-events b/hw/acpi/trace-events
index eb60b04f9b..78e0a8670e 100644
--- a/hw/acpi/trace-events
+++ b/hw/acpi/trace-events
@@ -55,6 +55,8 @@ piix4_gpe_writeb(uint64_t addr, unsigned width, uint64_t val) "addr: 0x%" PRIx64
 # tco.c
 tco_timer_reload(int ticks, int msec) "ticks=%d (%d ms)"
 tco_timer_expired(int timeouts_no, bool strap, bool no_reboot) "timeouts_no=%d no_reboot=%d/%d"
+tco_io_write(uint64_t addr, uint32_t val) "addr=0x%" PRIx64 " val=0x%" PRIx32
+tco_io_read(uint64_t addr, uint32_t val) "addr=0x%" PRIx64 " val=0x%" PRIx32
 
 # erst.c
 acpi_erst_reg_write(uint64_t addr, uint64_t val, unsigned size) "addr: 0x%04" PRIx64 " <== 0x%016" PRIx64 " (size: %u)"