1/*-
2 * Copyright (c) 2014 Hudson River Trading LLC
3 * Written by: John H. Baldwin <jhb@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: releng/11.0/usr.sbin/bhyve/ioapic.c 281887 2015-04-23 14:22:20Z jhb $");
30
31#include <sys/types.h>
32
33#include <machine/vmm.h>
34#include <vmmapi.h>
35
36#include "ioapic.h"
37
38/*
39 * Assign PCI INTx interrupts to I/O APIC pins in a round-robin
40 * fashion.  Note that we have no idea what the HPET is using, but the
41 * HPET is also programmable whereas this is intended for hardwired
42 * PCI interrupts.
43 *
44 * This assumes a single I/O APIC where pins >= 16 are permitted for
45 * PCI devices.
46 */
47static int pci_pins;
48
49void
50ioapic_init(struct vmctx *ctx)
51{
52
53	if (vm_ioapic_pincount(ctx, &pci_pins) < 0) {
54		pci_pins = 0;
55		return;
56	}
57
58	/* Ignore the first 16 pins. */
59	if (pci_pins <= 16) {
60		pci_pins = 0;
61		return;
62	}
63	pci_pins -= 16;
64}
65
66int
67ioapic_pci_alloc_irq(void)
68{
69	static int last_pin;
70
71	if (pci_pins == 0)
72		return (-1);
73	return (16 + (last_pin++ % pci_pins));
74}
75