Cleanly teardown and restore emulated device state on vm send/receive.

This cleans up events on a pause or resume, but also fixes an issue
where the vm_pipe event channels are not properly reinitialized on a
received guest leading to broken serial console.

OK pd@, mlarkin@

3 files changed, 21 insertions, 5 deletions

diff --git a/usr.sbin/vmd/i8253.c b/usr.sbin/vmd/i8253.c
index b5a6bc5ff97..24619ab363b 100644
--- a/usr.sbin/vmd/i8253.c
+++ b/usr.sbin/vmd/i8253.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: i8253.c,v 1.32 2020/06/28 16:52:45 pd Exp $ */
+/* $OpenBSD: i8253.c,v 1.33 2021/03/29 13:09:41 dv Exp $ */
 /*
  * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -412,6 +412,9 @@ i8253_restore(int fd, uint32_t vm_id)
 		    &i8253_channel[i]);
 		i8253_reset(i);
 	}
+
+	vm_pipe_init(&dev_pipe, i8253_pipe_dispatch);
+
 	return (0);
 }
 
@@ -421,6 +424,7 @@ i8253_stop()
 	int i;
 	for (i = 0; i < 3; i++)
 		evtimer_del(&i8253_channel[i].timer);
+	event_del(&dev_pipe.read_ev);
 }
 
 void
@@ -430,4 +434,5 @@ i8253_start()
 	for (i = 0; i < 3; i++)
 		if (i8253_channel[i].in_use)
 			i8253_reset(i);
+	event_add(&dev_pipe.read_ev, NULL);
 }
diff --git a/usr.sbin/vmd/mc146818.c b/usr.sbin/vmd/mc146818.c
index 7925bd9c459..311dc0c2caa 100644
--- a/usr.sbin/vmd/mc146818.c
+++ b/usr.sbin/vmd/mc146818.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mc146818.c,v 1.22 2020/06/28 16:52:45 pd Exp $ */
+/* $OpenBSD: mc146818.c,v 1.23 2021/03/29 13:09:41 dv Exp $ */
 /*
  * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -368,6 +368,9 @@ mc146818_restore(int fd, uint32_t vm_id)
 	memset(&rtc.per, 0, sizeof(struct event));
 	evtimer_set(&rtc.sec, rtc_fire1, NULL);
 	evtimer_set(&rtc.per, rtc_fireper, (void *)(intptr_t)rtc.vm_id);
+
+	vm_pipe_init(&dev_pipe, mc146818_pipe_dispatch);
+
 	return (0);
 }
 
@@ -376,11 +379,13 @@ mc146818_stop()
 {
 	evtimer_del(&rtc.per);
 	evtimer_del(&rtc.sec);
+	event_del(&dev_pipe.read_ev);
 }
 
 void
 mc146818_start()
 {
 	evtimer_add(&rtc.sec, &rtc.sec_tv);
+	event_add(&dev_pipe.read_ev, NULL);
 	rtc_reschedule_per();
 }
diff --git a/usr.sbin/vmd/ns8250.c b/usr.sbin/vmd/ns8250.c
index a1bc492b44b..24ab70f9a06 100644
--- a/usr.sbin/vmd/ns8250.c
+++ b/usr.sbin/vmd/ns8250.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ns8250.c,v 1.29 2020/06/28 16:52:45 pd Exp $ */
+/* $OpenBSD: ns8250.c,v 1.30 2021/03/29 13:09:41 dv Exp $ */
 /*
  * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -694,9 +694,7 @@ ns8250_restore(int fd, int con_fd, uint32_t vmid)
 	com1_dev.byte_out = 0;
 	com1_dev.regs.divlo = 1;
 	com1_dev.baudrate = 115200;
-	com1_dev.rate_tv.tv_usec = 10000;
 	com1_dev.pause_ct = (com1_dev.baudrate / 8) / 1000 * 10;
-	evtimer_set(&com1_dev.rate, ratelimit, NULL);
 
 	event_set(&com1_dev.event, com1_dev.fd, EV_READ | EV_PERSIST,
 	    com_rcv_event, (void *)(intptr_t)vmid);
@@ -704,6 +702,12 @@ ns8250_restore(int fd, int con_fd, uint32_t vmid)
 	event_set(&com1_dev.wake, com1_dev.fd, EV_WRITE,
 	    com_rcv_event, (void *)(intptr_t)vmid);
 
+	timerclear(&com1_dev.rate_tv);
+	com1_dev.rate_tv.tv_usec = 10000;
+	evtimer_set(&com1_dev.rate, ratelimit, NULL);
+
+	vm_pipe_init(&dev_pipe, ns8250_pipe_dispatch);
+
 	return (0);
 }
 
@@ -712,6 +716,7 @@ ns8250_stop()
 {
 	if(event_del(&com1_dev.event))
 		log_warn("could not delete ns8250 event handler");
+	event_del(&dev_pipe.read_ev);
 	evtimer_del(&com1_dev.rate);
 }
 
@@ -720,5 +725,6 @@ ns8250_start()
 {
 	event_add(&com1_dev.event, NULL);
 	event_add(&com1_dev.wake, NULL);
+	event_add(&dev_pipe.read_ev, NULL);
 	evtimer_add(&com1_dev.rate, &com1_dev.rate_tv);
 }