hpet: ignore high bits of comparator in 32-bit mode

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/timer/hpet.c

@@ -585,6 +585,10 @@ static void hpet_ram_write(void *opaque, hwaddr addr,
             }
             break;
         case HPET_TN_CMP + 4: // comparator register high order
+            if (timer->config & HPET_TN_32BIT) {
+                trace_hpet_ram_write_invalid_tn_cmp();
+                break;
+            }
             trace_hpet_ram_write_tn_cmp(4);
             if (!timer_is_periodic(timer)
                 || (timer->config & HPET_TN_SETVAL)) {

hw/timer/trace-events

@@ -111,6 +111,7 @@ hpet_ram_write_timer_id(uint64_t timer_id) "hpet_ram_writel timer_id = 0x%" PRIx
 hpet_ram_write_tn_cfg(void) "hpet_ram_writel HPET_TN_CFG"
 hpet_ram_write_invalid_tn_cfg(uint8_t reg_off) "invalid HPET_TN_CFG + %" PRIu8 " write"
 hpet_ram_write_tn_cmp(uint8_t reg_off) "hpet_ram_writel HPET_TN_CMP + %" PRIu8
+hpet_ram_write_invalid_tn_cmp(void) "invalid HPET_TN_CMP + 4 write"
 hpet_ram_write_invalid(void) "invalid hpet_ram_writel"
 hpet_ram_write_counter_write_while_enabled(void) "Writing counter while HPET enabled!"
 hpet_ram_write_counter_written(uint8_t reg_off, uint64_t value, uint64_t counter) "HPET counter + %" PRIu8 "written. crt = 0x%" PRIx64 " -> 0x%" PRIx64