Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.sbin/vmd/ns8250.c	Lines:	0	179	0.0 %
Date:	2017-11-13	Branches:	0	77	0.0 %


/* $OpenBSD: ns8250.c,v 1.12 2017/09/15 02:35:39 mlarkin Exp $ */
/*
 * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <dev/ic/comreg.h>

#include <machine/vmmvar.h>

#include <errno.h>
#include <event.h>
#include <pthread.h>
#include <string.h>
#include <unistd.h>

#include "ns8250.h"
#include "proc.h"
#include "vmd.h"
#include "vmm.h"
#include "atomicio.h"

extern char *__progname;
struct ns8250_dev com1_dev;

static void com_rcv_event(int, short, void *);
static void com_rcv(struct ns8250_dev *, uint32_t, uint32_t);

/*
 * ratelimit
 *
 * Timeout callback function used when we have to slow down the output rate
 * from the emulated serial port.
 *
 * Parameters:
 *  fd: unused
 *  type: unused
 *  arg: unused
 */
static void
ratelimit(int fd, short type, void *arg)
{
	/* Set TXRDY and clear "no pending interrupt" */
	com1_dev.regs.iir |= IIR_TXRDY;
	com1_dev.regs.iir &= ~IIR_NOPEND;
	vcpu_assert_pic_irq(com1_dev.vmid, 0, com1_dev.irq);
}

void
ns8250_init(int fd, uint32_t vmid)
{
	int ret;

	memset(&com1_dev, 0, sizeof(com1_dev));
	ret = pthread_mutex_init(&com1_dev.mutex, NULL);
	if (ret) {
		errno = ret;
		fatal("could not initialize com1 mutex");
	}
	com1_dev.fd = fd;
	com1_dev.irq = 4;
	com1_dev.rcv_pending = 0;
	com1_dev.vmid = vmid;
	com1_dev.byte_out = 0;
	com1_dev.regs.divlo = 1;
	com1_dev.baudrate = 115200;

	/*
	 * Our serial port is essentially instantaneous, with infinite
	 * baudrate capability. To adjust for the selected baudrate,
	 * we calculate how many characters could be transmitted in a 10ms
	 * period (pause_ct) and then delay 10ms after each pause_ct sized
	 * group of characters have been transmitted. Since it takes nearly
	 * zero time to send the actual characters, the total amount of time
	 * spent is roughly equal to what it would be on real hardware.
	 *
	 * To make things simple, we don't adjust for different sized bytes
	 * (and parity, stop bits, etc) and simply assume each character
	 * output is 8 bits.
	 */
	com1_dev.pause_ct = (com1_dev.baudrate / 8) / 1000 * 10;

	event_set(&com1_dev.event, com1_dev.fd, EV_READ | EV_PERSIST,
	    com_rcv_event, (void *)(intptr_t)vmid);
	event_add(&com1_dev.event, NULL);

	/* Rate limiter for simulating baud rate */
	timerclear(&com1_dev.rate_tv);
	com1_dev.rate_tv.tv_usec = 10000;
	evtimer_set(&com1_dev.rate, ratelimit, NULL);
}

static void
com_rcv_event(int fd, short kind, void *arg)
{
	mutex_lock(&com1_dev.mutex);

	/*
	 * We already have other data pending to be received. The data that
	 * has become available now will be moved to the com port later.
	 */
	if (com1_dev.rcv_pending) {
		mutex_unlock(&com1_dev.mutex);
		return;
	}

	if (com1_dev.regs.lsr & LSR_RXRDY)
		com1_dev.rcv_pending = 1;
	else {
		com_rcv(&com1_dev, (uintptr_t)arg, 0);

		/* If pending interrupt, inject */
		if ((com1_dev.regs.iir & IIR_NOPEND) == 0) {
			/* XXX: vcpu_id */
			vcpu_assert_pic_irq((uintptr_t)arg, 0, com1_dev.irq);
		}
	}

	mutex_unlock(&com1_dev.mutex);
}

/*
 * com_rcv
 *
 * Move received byte into com data register.
 * Must be called with the mutex of the com device acquired
 */
static void
com_rcv(struct ns8250_dev *com, uint32_t vm_id, uint32_t vcpu_id)
{
	char ch;
	ssize_t sz;

	/*
	 * Is there a new character available on com1?
	 * If so, consume the character, buffer it into the com1 data register
	 * assert IRQ4, and set the line status register RXRDY bit.
	 */
	sz = read(com->fd, &ch, sizeof(char));
	if (sz == -1) {
		/*
		 * If we get EAGAIN, we'll retry and get the character later.
		 * This error can happen when typing two characters at once
		 * at the keyboard, for example.
		 */
		if (errno != EAGAIN)
			log_warn("unexpected read error on com device");
	} else if (sz != 1)
		log_warnx("unexpected read return value on com device");
	else {
		com->regs.lsr |= LSR_RXRDY;
		com->regs.data = ch;

		if (com->regs.ier & IER_ERXRDY) {
			com->regs.iir |= IIR_RXRDY;
			com->regs.iir &= ~IIR_NOPEND;
		}
	}

	com->rcv_pending = fd_hasdata(com->fd);
}

/*
 * vcpu_process_com_data
 *
 * Emulate in/out instructions to the com1 (ns8250) UART data register
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 *
 * Return value:
 *  interrupt to inject, or 0xFF if nothing to inject
 */
uint8_t
vcpu_process_com_data(union vm_exit *vei, uint32_t vm_id, uint32_t vcpu_id)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * The guest wrote to the data register. Since we are emulating a
	 * no-fifo chip, write the character immediately to the pty and
	 * assert TXRDY in IIR (if the guest has requested TXRDY interrupt
	 * reporting)
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		if (com1_dev.regs.lcr & LCR_DLAB) {
			com1_dev.regs.divlo = vei->vei.vei_data;
			return 0xFF;
		}

		write(com1_dev.fd, &vei->vei.vei_data, 1);
		com1_dev.byte_out++;

		if (com1_dev.regs.ier & IER_ETXRDY) {
			/* Limit output rate if needed */
			if (com1_dev.byte_out % com1_dev.pause_ct == 0) {
				evtimer_add(&com1_dev.rate, &com1_dev.rate_tv);
			} else {
				/* Set TXRDY and clear "no pending interrupt" */
				com1_dev.regs.iir |= IIR_TXRDY;
				com1_dev.regs.iir &= ~IIR_NOPEND;
			}
		}
	} else {
		if (com1_dev.regs.lcr & LCR_DLAB) {
			set_return_data(vei, com1_dev.regs.divlo);
			return 0xFF;
		}
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * The guest read from the data register. Check to see if
		 * there is data available (RXRDY) and if so, consume the
		 * input data and return to the guest. Also clear the
		 * interrupt info register regardless.
		 */
		if (com1_dev.regs.lsr & LSR_RXRDY) {
			set_return_data(vei, com1_dev.regs.data);
			com1_dev.regs.data = 0x0;
			com1_dev.regs.lsr &= ~LSR_RXRDY;
		} else {
			set_return_data(vei, com1_dev.regs.data);
			log_warnx("%s: guest reading com1 when not ready", __func__);
		}

		/* Reading the data register always clears RXRDY from IIR */
		com1_dev.regs.iir &= ~IIR_RXRDY;

		/*
		 * Clear "interrupt pending" by setting IIR low bit to 1
		 * if no interrupt are pending
		 */
		if (com1_dev.regs.iir == 0x0)
			com1_dev.regs.iir = 0x1;

		if (com1_dev.rcv_pending)
			com_rcv(&com1_dev, vm_id, vcpu_id);
	}

	/* If pending interrupt, make sure it gets injected */
	if ((com1_dev.regs.iir & IIR_NOPEND) == 0)
		return (com1_dev.irq);

	return (0xFF);
}

/*
 * vcpu_process_com_lcr
 *
 * Emulate in/out instructions to the com1 (ns8250) UART line control register
 *
 * Paramters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_lcr(union vm_exit *vei)
{
	uint8_t data = (uint8_t)vei->vei.vei_data;
	uint16_t divisor;

	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write content to line control register
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		if (com1_dev.regs.lcr & LCR_DLAB) {
			if (!(data & LCR_DLAB)) {
				if (com1_dev.regs.divlo == 0 &&
				    com1_dev.regs.divhi == 0) {
					log_warnx("%s: ignoring invalid "
					    "baudrate", __func__);
				} else {
					divisor = com1_dev.regs.divlo |
					     com1_dev.regs.divhi << 8;
					com1_dev.baudrate = 115200 / divisor;
					com1_dev.pause_ct =
					    (com1_dev.baudrate / 8) / 1000 * 10;
				}

				log_debug("%s: set baudrate = %d", __func__,
				    com1_dev.baudrate);
			}
		}
		com1_dev.regs.lcr = (uint8_t)vei->vei.vei_data;
	} else {
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read line control register
		 */
		set_return_data(vei, com1_dev.regs.lcr);
	}
}

/*
 * vcpu_process_com_iir
 *
 * Emulate in/out instructions to the com1 (ns8250) UART interrupt information
 * register. Note that writes to this register actually are to a different
 * register, the FCR (FIFO control register) that we don't emulate but still
 * consume the data provided.
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_iir(union vm_exit *vei)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write to FCR
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		com1_dev.regs.fcr = vei->vei.vei_data;
	} else {
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read IIR. Reading the IIR resets the TXRDY bit in the IIR
		 * after the data is read.
		 */
		set_return_data(vei, com1_dev.regs.iir);
		com1_dev.regs.iir &= ~IIR_TXRDY;

		/*
		 * Clear "interrupt pending" by setting IIR low bit to 1
		 * if no interrupts are pending
		 */
		if (com1_dev.regs.iir == 0x0)
			com1_dev.regs.iir = 0x1;
	}
}

/*
 * vcpu_process_com_mcr
 *
 * Emulate in/out instructions to the com1 (ns8250) UART modem control
 * register.
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_mcr(union vm_exit *vei)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write to MCR
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		com1_dev.regs.mcr = vei->vei.vei_data;
	} else {
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read from MCR
		 */
		set_return_data(vei, com1_dev.regs.mcr);
	}
}

/*
 * vcpu_process_com_lsr
 *
 * Emulate in/out instructions to the com1 (ns8250) UART line status register.
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_lsr(union vm_exit *vei)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write to LSR. This is an illegal operation, so we just log it and
	 * continue.
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		log_warnx("%s: LSR UART write 0x%x unsupported",
		    __progname, vei->vei.vei_data);
	} else {
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read from LSR. We always report TXRDY and TSRE since we
		 * can process output characters immediately (at any time).
		 */
		set_return_data(vei, com1_dev.regs.lsr | LSR_TSRE | LSR_TXRDY);
	}
}

/*
 * vcpu_process_com_msr
 *
 * Emulate in/out instructions to the com1 (ns8250) UART modem status register.
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_msr(union vm_exit *vei)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write to MSR. This is an illegal operation, so we just log it and
	 * continue.
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		log_warnx("%s: MSR UART write 0x%x unsupported",
		    __progname, vei->vei.vei_data);
	} else {
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read from MSR. We always report DCD, DSR, and CTS.
		 */
		set_return_data(vei, com1_dev.regs.lsr | MSR_DCD | MSR_DSR |
		    MSR_CTS);
	}
}

/*
 * vcpu_process_com_scr
 *
 * Emulate in/out instructions to the com1 (ns8250) UART scratch register.
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_scr(union vm_exit *vei)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write to SCR
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		com1_dev.regs.scr = vei->vei.vei_data;
	} else {
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read from SCR
		 */
		set_return_data(vei, com1_dev.regs.scr);
	}
}

/*
 * vcpu_process_com_ier
 *
 * Emulate in/out instructions to the com1 (ns8250) UART interrupt enable
 * register.
 *
 * Parameters:
 *  vei: vm exit information from vmm(4) containing information on the in/out
 *      instruction being performed
 */
void
vcpu_process_com_ier(union vm_exit *vei)
{
	/*
	 * vei_dir == VEI_DIR_OUT : out instruction
	 *
	 * Write to IER
	 */
	if (vei->vei.vei_dir == VEI_DIR_OUT) {
		if (com1_dev.regs.lcr & LCR_DLAB) {
			com1_dev.regs.divhi = vei->vei.vei_data;
			return;
		}
		com1_dev.regs.ier = vei->vei.vei_data;
		if (com1_dev.regs.ier & IER_ETXRDY)
			com1_dev.regs.iir |= IIR_TXRDY;
	} else {
		if (com1_dev.regs.lcr & LCR_DLAB) {
			set_return_data(vei, com1_dev.regs.divhi);
			return;
		}
		/*
		 * vei_dir == VEI_DIR_IN : in instruction
		 *
		 * Read from IER
		 */
		set_return_data(vei, com1_dev.regs.ier);
	}
}

/*
 * vcpu_exit_com
 *
 * Process com1 (ns8250) UART exits. vmd handles most basic 8250
 * features
 *
 * Parameters:
 *  vrp: vcpu run parameters containing guest state for this exit
 *
 * Return value:
 *  Interrupt to inject to the guest VM, or 0xFF if no interrupt should
 *      be injected.
 */
uint8_t
vcpu_exit_com(struct vm_run_params *vrp)
{
	uint8_t intr = 0xFF;
	union vm_exit *vei = vrp->vrp_exit;

	mutex_lock(&com1_dev.mutex);

	switch (vei->vei.vei_port) {
	case COM1_LCR:
		vcpu_process_com_lcr(vei);
		break;
	case COM1_IER:
		vcpu_process_com_ier(vei);
		break;
	case COM1_IIR:
		vcpu_process_com_iir(vei);
		break;
	case COM1_MCR:
		vcpu_process_com_mcr(vei);
		break;
	case COM1_LSR:
		vcpu_process_com_lsr(vei);
		break;
	case COM1_MSR:
		vcpu_process_com_msr(vei);
		break;
	case COM1_SCR:
		vcpu_process_com_scr(vei);
		break;
	case COM1_DATA:
		intr = vcpu_process_com_data(vei, vrp->vrp_vm_id,
		    vrp->vrp_vcpu_id);
		break;
	}

	mutex_unlock(&com1_dev.mutex);

	if ((com1_dev.regs.iir & IIR_NOPEND)) {
		/* XXX: vcpu_id */
		vcpu_deassert_pic_irq(com1_dev.vmid, 0, com1_dev.irq);
	}

	return (intr);
}

int
ns8250_dump(int fd)
{
	log_debug("%s: sending UART", __func__);
	if (atomicio(vwrite, fd, &com1_dev.regs,
	    sizeof(com1_dev.regs)) != sizeof(com1_dev.regs)) {
		log_warnx("%s: error writing UART to fd", __func__);
		return (-1);
	}
	return (0);
}

int
ns8250_restore(int fd, int con_fd, uint32_t vmid)
{
	int ret;
	log_debug("%s: receiving UART", __func__);
	if (atomicio(read, fd, &com1_dev.regs,
	    sizeof(com1_dev.regs)) != sizeof(com1_dev.regs)) {
		log_warnx("%s: error reading UART from fd", __func__);
		return (-1);
	}

	ret = pthread_mutex_init(&com1_dev.mutex, NULL);
	if (ret) {
		errno = ret;
		fatal("could not initialize com1 mutex");
	}
	com1_dev.fd = con_fd;
	com1_dev.irq = 4;
	com1_dev.rcv_pending = 0;
	com1_dev.vmid = 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);
	event_add(&com1_dev.event, NULL);
	return (0);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: ns8250.c,v 1.12 2017/09/15 02:35:39 mlarkin Exp $ */
2			/*
3			* Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
4			*
5			* Permission to use, copy, modify, and distribute this software for any
6			* purpose with or without fee is hereby granted, provided that the above
7			* copyright notice and this permission notice appear in all copies.
8			*
9			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15			* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16			*/
17
18			#include <sys/types.h>
19
20			#include <dev/ic/comreg.h>
21
22			#include <machine/vmmvar.h>
23
24			#include <errno.h>
25			#include <event.h>
26			#include <pthread.h>
27			#include <string.h>
28			#include <unistd.h>
29
30			#include "ns8250.h"
31			#include "proc.h"
32			#include "vmd.h"
33			#include "vmm.h"
34			#include "atomicio.h"
35
36			extern char *__progname;
37			struct ns8250_dev com1_dev;
38
39			static void com_rcv_event(int, short, void *);
40			static void com_rcv(struct ns8250_dev *, uint32_t, uint32_t);
41
42			/*
43			* ratelimit
44			*
45			* Timeout callback function used when we have to slow down the output rate
46			* from the emulated serial port.
47			*
48			* Parameters:
49			* fd: unused
50			* type: unused
51			* arg: unused
52			*/
53			static void
54			ratelimit(int fd, short type, void *arg)
55			{
56			/* Set TXRDY and clear "no pending interrupt" */
57			com1_dev.regs.iir \|= IIR_TXRDY;
58			com1_dev.regs.iir &= ~IIR_NOPEND;
59			vcpu_assert_pic_irq(com1_dev.vmid, 0, com1_dev.irq);
60			}
61
62			void
63			ns8250_init(int fd, uint32_t vmid)
64			{
65			int ret;
66
67			memset(&com1_dev, 0, sizeof(com1_dev));
68			ret = pthread_mutex_init(&com1_dev.mutex, NULL);
69			if (ret) {
70			errno = ret;
71			fatal("could not initialize com1 mutex");
72			}
73			com1_dev.fd = fd;
74			com1_dev.irq = 4;
75			com1_dev.rcv_pending = 0;
76			com1_dev.vmid = vmid;
77			com1_dev.byte_out = 0;
78			com1_dev.regs.divlo = 1;
79			com1_dev.baudrate = 115200;
80
81			/*
82			* Our serial port is essentially instantaneous, with infinite
83			* baudrate capability. To adjust for the selected baudrate,
84			* we calculate how many characters could be transmitted in a 10ms
85			* period (pause_ct) and then delay 10ms after each pause_ct sized
86			* group of characters have been transmitted. Since it takes nearly
87			* zero time to send the actual characters, the total amount of time
88			* spent is roughly equal to what it would be on real hardware.
89			*
90			* To make things simple, we don't adjust for different sized bytes
91			* (and parity, stop bits, etc) and simply assume each character
92			* output is 8 bits.
93			*/
94			com1_dev.pause_ct = (com1_dev.baudrate / 8) / 1000 * 10;
95
96			event_set(&com1_dev.event, com1_dev.fd, EV_READ \| EV_PERSIST,
97			com_rcv_event, (void *)(intptr_t)vmid);
98			event_add(&com1_dev.event, NULL);
99
100			/* Rate limiter for simulating baud rate */
101			timerclear(&com1_dev.rate_tv);
102			com1_dev.rate_tv.tv_usec = 10000;
103			evtimer_set(&com1_dev.rate, ratelimit, NULL);
104			}
105
106			static void
107			com_rcv_event(int fd, short kind, void *arg)
108			{
109			mutex_lock(&com1_dev.mutex);
110
111			/*
112			* We already have other data pending to be received. The data that
113			* has become available now will be moved to the com port later.
114			*/
115			if (com1_dev.rcv_pending) {
116			mutex_unlock(&com1_dev.mutex);
117			return;
118			}
119
120			if (com1_dev.regs.lsr & LSR_RXRDY)
121			com1_dev.rcv_pending = 1;
122			else {
123			com_rcv(&com1_dev, (uintptr_t)arg, 0);
124
125			/* If pending interrupt, inject */
126			if ((com1_dev.regs.iir & IIR_NOPEND) == 0) {
127			/* XXX: vcpu_id */
128			vcpu_assert_pic_irq((uintptr_t)arg, 0, com1_dev.irq);
129			}
130			}
131
132			mutex_unlock(&com1_dev.mutex);
133			}
134
135			/*
136			* com_rcv
137			*
138			* Move received byte into com data register.
139			* Must be called with the mutex of the com device acquired
140			*/
141			static void
142			com_rcv(struct ns8250_dev *com, uint32_t vm_id, uint32_t vcpu_id)
143			{
144			char ch;
145			ssize_t sz;
146
147			/*
148			* Is there a new character available on com1?
149			* If so, consume the character, buffer it into the com1 data register
150			* assert IRQ4, and set the line status register RXRDY bit.
151			*/
152			sz = read(com->fd, &ch, sizeof(char));
153			if (sz == -1) {
154			/*
155			* If we get EAGAIN, we'll retry and get the character later.
156			* This error can happen when typing two characters at once
157			* at the keyboard, for example.
158			*/
159			if (errno != EAGAIN)
160			log_warn("unexpected read error on com device");
161			} else if (sz != 1)
162			log_warnx("unexpected read return value on com device");
163			else {
164			com->regs.lsr \|= LSR_RXRDY;
165			com->regs.data = ch;
166
167			if (com->regs.ier & IER_ERXRDY) {
168			com->regs.iir \|= IIR_RXRDY;
169			com->regs.iir &= ~IIR_NOPEND;
170			}
171			}
172
173			com->rcv_pending = fd_hasdata(com->fd);
174			}
175
176			/*
177			* vcpu_process_com_data
178			*
179			* Emulate in/out instructions to the com1 (ns8250) UART data register
180			*
181			* Parameters:
182			* vei: vm exit information from vmm(4) containing information on the in/out
183			* instruction being performed
184			*
185			* Return value:
186			* interrupt to inject, or 0xFF if nothing to inject
187			*/
188			uint8_t
189			vcpu_process_com_data(union vm_exit *vei, uint32_t vm_id, uint32_t vcpu_id)
190			{
191			/*
192			* vei_dir == VEI_DIR_OUT : out instruction
193			*
194			* The guest wrote to the data register. Since we are emulating a
195			* no-fifo chip, write the character immediately to the pty and
196			* assert TXRDY in IIR (if the guest has requested TXRDY interrupt
197			* reporting)
198			*/
199			if (vei->vei.vei_dir == VEI_DIR_OUT) {
200			if (com1_dev.regs.lcr & LCR_DLAB) {
201			com1_dev.regs.divlo = vei->vei.vei_data;
202			return 0xFF;
203			}
204
205			write(com1_dev.fd, &vei->vei.vei_data, 1);
206			com1_dev.byte_out++;
207
208			if (com1_dev.regs.ier & IER_ETXRDY) {
209			/* Limit output rate if needed */
210			if (com1_dev.byte_out % com1_dev.pause_ct == 0) {
211			evtimer_add(&com1_dev.rate, &com1_dev.rate_tv);
212			} else {
213			/* Set TXRDY and clear "no pending interrupt" */
214			com1_dev.regs.iir \|= IIR_TXRDY;
215			com1_dev.regs.iir &= ~IIR_NOPEND;
216			}
217			}
218			} else {
219			if (com1_dev.regs.lcr & LCR_DLAB) {
220			set_return_data(vei, com1_dev.regs.divlo);
221			return 0xFF;
222			}
223			/*
224			* vei_dir == VEI_DIR_IN : in instruction
225			*
226			* The guest read from the data register. Check to see if
227			* there is data available (RXRDY) and if so, consume the
228			* input data and return to the guest. Also clear the
229			* interrupt info register regardless.
230			*/
231			if (com1_dev.regs.lsr & LSR_RXRDY) {
232			set_return_data(vei, com1_dev.regs.data);
233			com1_dev.regs.data = 0x0;
234			com1_dev.regs.lsr &= ~LSR_RXRDY;
235			} else {
236			set_return_data(vei, com1_dev.regs.data);
237			log_warnx("%s: guest reading com1 when not ready", __func__);
238			}
239
240			/* Reading the data register always clears RXRDY from IIR */
241			com1_dev.regs.iir &= ~IIR_RXRDY;
242
243			/*
244			* Clear "interrupt pending" by setting IIR low bit to 1
245			* if no interrupt are pending
246			*/
247			if (com1_dev.regs.iir == 0x0)
248			com1_dev.regs.iir = 0x1;
249
250			if (com1_dev.rcv_pending)
251			com_rcv(&com1_dev, vm_id, vcpu_id);
252			}
253
254			/* If pending interrupt, make sure it gets injected */
255			if ((com1_dev.regs.iir & IIR_NOPEND) == 0)
256			return (com1_dev.irq);
257
258			return (0xFF);
259			}
260
261			/*
262			* vcpu_process_com_lcr
263			*
264			* Emulate in/out instructions to the com1 (ns8250) UART line control register
265			*
266			* Paramters:
267			* vei: vm exit information from vmm(4) containing information on the in/out
268			* instruction being performed
269			*/
270			void
271			vcpu_process_com_lcr(union vm_exit *vei)
272			{
273			uint8_t data = (uint8_t)vei->vei.vei_data;
274			uint16_t divisor;
275
276			/*
277			* vei_dir == VEI_DIR_OUT : out instruction
278			*
279			* Write content to line control register
280			*/
281			if (vei->vei.vei_dir == VEI_DIR_OUT) {
282			if (com1_dev.regs.lcr & LCR_DLAB) {
283			if (!(data & LCR_DLAB)) {
284			if (com1_dev.regs.divlo == 0 &&
285			com1_dev.regs.divhi == 0) {
286			log_warnx("%s: ignoring invalid "
287			"baudrate", __func__);
288			} else {
289			divisor = com1_dev.regs.divlo \|
290			com1_dev.regs.divhi << 8;
291			com1_dev.baudrate = 115200 / divisor;
292			com1_dev.pause_ct =
293			(com1_dev.baudrate / 8) / 1000 * 10;
294			}
295
296			log_debug("%s: set baudrate = %d", __func__,
297			com1_dev.baudrate);
298			}
299			}
300			com1_dev.regs.lcr = (uint8_t)vei->vei.vei_data;
301			} else {
302			/*
303			* vei_dir == VEI_DIR_IN : in instruction
304			*
305			* Read line control register
306			*/
307			set_return_data(vei, com1_dev.regs.lcr);
308			}
309			}
310
311			/*
312			* vcpu_process_com_iir
313			*
314			* Emulate in/out instructions to the com1 (ns8250) UART interrupt information
315			* register. Note that writes to this register actually are to a different
316			* register, the FCR (FIFO control register) that we don't emulate but still
317			* consume the data provided.
318			*
319			* Parameters:
320			* vei: vm exit information from vmm(4) containing information on the in/out
321			* instruction being performed
322			*/
323			void
324			vcpu_process_com_iir(union vm_exit *vei)
325			{
326			/*
327			* vei_dir == VEI_DIR_OUT : out instruction
328			*
329			* Write to FCR
330			*/
331			if (vei->vei.vei_dir == VEI_DIR_OUT) {
332			com1_dev.regs.fcr = vei->vei.vei_data;
333			} else {
334			/*
335			* vei_dir == VEI_DIR_IN : in instruction
336			*
337			* Read IIR. Reading the IIR resets the TXRDY bit in the IIR
338			* after the data is read.
339			*/
340			set_return_data(vei, com1_dev.regs.iir);
341			com1_dev.regs.iir &= ~IIR_TXRDY;
342
343			/*
344			* Clear "interrupt pending" by setting IIR low bit to 1
345			* if no interrupts are pending
346			*/
347			if (com1_dev.regs.iir == 0x0)
348			com1_dev.regs.iir = 0x1;
349			}
350			}
351
352			/*
353			* vcpu_process_com_mcr
354			*
355			* Emulate in/out instructions to the com1 (ns8250) UART modem control
356			* register.
357			*
358			* Parameters:
359			* vei: vm exit information from vmm(4) containing information on the in/out
360			* instruction being performed
361			*/
362			void
363			vcpu_process_com_mcr(union vm_exit *vei)
364			{
365			/*
366			* vei_dir == VEI_DIR_OUT : out instruction
367			*
368			* Write to MCR
369			*/
370			if (vei->vei.vei_dir == VEI_DIR_OUT) {
371			com1_dev.regs.mcr = vei->vei.vei_data;
372			} else {
373			/*
374			* vei_dir == VEI_DIR_IN : in instruction
375			*
376			* Read from MCR
377			*/
378			set_return_data(vei, com1_dev.regs.mcr);
379			}
380			}
381
382			/*
383			* vcpu_process_com_lsr
384			*
385			* Emulate in/out instructions to the com1 (ns8250) UART line status register.
386			*
387			* Parameters:
388			* vei: vm exit information from vmm(4) containing information on the in/out
389			* instruction being performed
390			*/
391			void
392			vcpu_process_com_lsr(union vm_exit *vei)
393			{
394			/*
395			* vei_dir == VEI_DIR_OUT : out instruction
396			*
397			* Write to LSR. This is an illegal operation, so we just log it and
398			* continue.
399			*/
400			if (vei->vei.vei_dir == VEI_DIR_OUT) {
401			log_warnx("%s: LSR UART write 0x%x unsupported",
402			__progname, vei->vei.vei_data);
403			} else {
404			/*
405			* vei_dir == VEI_DIR_IN : in instruction
406			*
407			* Read from LSR. We always report TXRDY and TSRE since we
408			* can process output characters immediately (at any time).
409			*/
410			set_return_data(vei, com1_dev.regs.lsr \| LSR_TSRE \| LSR_TXRDY);
411			}
412			}
413
414			/*
415			* vcpu_process_com_msr
416			*
417			* Emulate in/out instructions to the com1 (ns8250) UART modem status register.
418			*
419			* Parameters:
420			* vei: vm exit information from vmm(4) containing information on the in/out
421			* instruction being performed
422			*/
423			void
424			vcpu_process_com_msr(union vm_exit *vei)
425			{
426			/*
427			* vei_dir == VEI_DIR_OUT : out instruction
428			*
429			* Write to MSR. This is an illegal operation, so we just log it and
430			* continue.
431			*/
432			if (vei->vei.vei_dir == VEI_DIR_OUT) {
433			log_warnx("%s: MSR UART write 0x%x unsupported",
434			__progname, vei->vei.vei_data);
435			} else {
436			/*
437			* vei_dir == VEI_DIR_IN : in instruction
438			*
439			* Read from MSR. We always report DCD, DSR, and CTS.
440			*/
441			set_return_data(vei, com1_dev.regs.lsr \| MSR_DCD \| MSR_DSR \|
442			MSR_CTS);
443			}
444			}
445
446			/*
447			* vcpu_process_com_scr
448			*
449			* Emulate in/out instructions to the com1 (ns8250) UART scratch register.
450			*
451			* Parameters:
452			* vei: vm exit information from vmm(4) containing information on the in/out
453			* instruction being performed
454			*/
455			void
456			vcpu_process_com_scr(union vm_exit *vei)
457			{
458			/*
459			* vei_dir == VEI_DIR_OUT : out instruction
460			*
461			* Write to SCR
462			*/
463			if (vei->vei.vei_dir == VEI_DIR_OUT) {
464			com1_dev.regs.scr = vei->vei.vei_data;
465			} else {
466			/*
467			* vei_dir == VEI_DIR_IN : in instruction
468			*
469			* Read from SCR
470			*/
471			set_return_data(vei, com1_dev.regs.scr);
472			}
473			}
474
475			/*
476			* vcpu_process_com_ier
477			*
478			* Emulate in/out instructions to the com1 (ns8250) UART interrupt enable
479			* register.
480			*
481			* Parameters:
482			* vei: vm exit information from vmm(4) containing information on the in/out
483			* instruction being performed
484			*/
485			void
486			vcpu_process_com_ier(union vm_exit *vei)
487			{
488			/*
489			* vei_dir == VEI_DIR_OUT : out instruction
490			*
491			* Write to IER
492			*/
493			if (vei->vei.vei_dir == VEI_DIR_OUT) {
494			if (com1_dev.regs.lcr & LCR_DLAB) {
495			com1_dev.regs.divhi = vei->vei.vei_data;
496			return;
497			}
498			com1_dev.regs.ier = vei->vei.vei_data;
499			if (com1_dev.regs.ier & IER_ETXRDY)
500			com1_dev.regs.iir \|= IIR_TXRDY;
501			} else {
502			if (com1_dev.regs.lcr & LCR_DLAB) {
503			set_return_data(vei, com1_dev.regs.divhi);
504			return;
505			}
506			/*
507			* vei_dir == VEI_DIR_IN : in instruction
508			*
509			* Read from IER
510			*/
511			set_return_data(vei, com1_dev.regs.ier);
512			}
513			}
514
515			/*
516			* vcpu_exit_com
517			*
518			* Process com1 (ns8250) UART exits. vmd handles most basic 8250
519			* features
520			*
521			* Parameters:
522			* vrp: vcpu run parameters containing guest state for this exit
523			*
524			* Return value:
525			* Interrupt to inject to the guest VM, or 0xFF if no interrupt should
526			* be injected.
527			*/
528			uint8_t
529			vcpu_exit_com(struct vm_run_params *vrp)
530			{
531			uint8_t intr = 0xFF;
532			union vm_exit *vei = vrp->vrp_exit;
533
534			mutex_lock(&com1_dev.mutex);
535
536			switch (vei->vei.vei_port) {
537			case COM1_LCR:
538			vcpu_process_com_lcr(vei);
539			break;
540			case COM1_IER:
541			vcpu_process_com_ier(vei);
542			break;
543			case COM1_IIR:
544			vcpu_process_com_iir(vei);
545			break;
546			case COM1_MCR:
547			vcpu_process_com_mcr(vei);
548			break;
549			case COM1_LSR:
550			vcpu_process_com_lsr(vei);
551			break;
552			case COM1_MSR:
553			vcpu_process_com_msr(vei);
554			break;
555			case COM1_SCR:
556			vcpu_process_com_scr(vei);
557			break;
558			case COM1_DATA:
559			intr = vcpu_process_com_data(vei, vrp->vrp_vm_id,
560			vrp->vrp_vcpu_id);
561			break;
562			}
563
564			mutex_unlock(&com1_dev.mutex);
565
566			if ((com1_dev.regs.iir & IIR_NOPEND)) {
567			/* XXX: vcpu_id */
568			vcpu_deassert_pic_irq(com1_dev.vmid, 0, com1_dev.irq);
569			}
570
571			return (intr);
572			}
573
574			int
575			ns8250_dump(int fd)
576			{
577			log_debug("%s: sending UART", __func__);
578			if (atomicio(vwrite, fd, &com1_dev.regs,
579			sizeof(com1_dev.regs)) != sizeof(com1_dev.regs)) {
580			log_warnx("%s: error writing UART to fd", __func__);
581			return (-1);
582			}
583			return (0);
584			}
585
586			int
587			ns8250_restore(int fd, int con_fd, uint32_t vmid)
588			{
589			int ret;
590			log_debug("%s: receiving UART", __func__);
591			if (atomicio(read, fd, &com1_dev.regs,
592			sizeof(com1_dev.regs)) != sizeof(com1_dev.regs)) {
593			log_warnx("%s: error reading UART from fd", __func__);
594			return (-1);
595			}
596
597			ret = pthread_mutex_init(&com1_dev.mutex, NULL);
598			if (ret) {
599			errno = ret;
600			fatal("could not initialize com1 mutex");
601			}
602			com1_dev.fd = con_fd;
603			com1_dev.irq = 4;
604			com1_dev.rcv_pending = 0;
605			com1_dev.vmid = vmid;
606			com1_dev.byte_out = 0;
607			com1_dev.regs.divlo = 1;
608			com1_dev.baudrate = 115200;
609			com1_dev.rate_tv.tv_usec = 10000;
610			com1_dev.pause_ct = (com1_dev.baudrate / 8) / 1000 * 10;
611			evtimer_set(&com1_dev.rate, ratelimit, NULL);
612
613			event_set(&com1_dev.event, com1_dev.fd, EV_READ \| EV_PERSIST,
614			com_rcv_event, (void *)(intptr_t)vmid);
615			event_add(&com1_dev.event, NULL);
616			return (0);
617			}