1/*
2 * Virtio PCI driver
3 *
4 * This module allows virtio devices to be used over a virtual PCI device.
5 * This can be used with QEMU based VMMs like KVM or Xen.
6 *
7 * Copyright IBM Corp. 2007
8 *
9 * Authors:
10 *  Anthony Liguori  <aliguori@us.ibm.com>
11 *
12 * This header is BSD licensed so anyone can use the definitions to implement
13 * compatible drivers/servers.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 *    notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 *    notice, this list of conditions and the following disclaimer in the
22 *    documentation and/or other materials provided with the distribution.
23 * 3. Neither the name of IBM nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#ifndef _LINUX_VIRTIO_PCI_H
40#define _LINUX_VIRTIO_PCI_H
41
42#include <linux/virtio_config.h>
43
44/* A 32-bit r/o bitmask of the features supported by the host */
45#define VIRTIO_PCI_HOST_FEATURES	0
46
47/* A 32-bit r/w bitmask of features activated by the guest */
48#define VIRTIO_PCI_GUEST_FEATURES	4
49
50/* A 32-bit r/w PFN for the currently selected queue */
51#define VIRTIO_PCI_QUEUE_PFN		8
52
53/* A 16-bit r/o queue size for the currently selected queue */
54#define VIRTIO_PCI_QUEUE_NUM		12
55
56/* A 16-bit r/w queue selector */
57#define VIRTIO_PCI_QUEUE_SEL		14
58
59/* A 16-bit r/w queue notifier */
60#define VIRTIO_PCI_QUEUE_NOTIFY		16
61
62/* An 8-bit device status register.  */
63#define VIRTIO_PCI_STATUS		18
64
65/* An 8-bit r/o interrupt status register.  Reading the value will return the
66 * current contents of the ISR and will also clear it.  This is effectively
67 * a read-and-acknowledge. */
68#define VIRTIO_PCI_ISR			19
69
70/* The bit of the ISR which indicates a device configuration change. */
71#define VIRTIO_PCI_ISR_CONFIG		0x2
72
73/* MSI-X registers: only enabled if MSI-X is enabled. */
74/* A 16-bit vector for configuration changes. */
75#define VIRTIO_MSI_CONFIG_VECTOR        20
76/* A 16-bit vector for selected queue notifications. */
77#define VIRTIO_MSI_QUEUE_VECTOR         22
78/* Vector value used to disable MSI for queue */
79#define VIRTIO_MSI_NO_VECTOR            0xffff
80
81/* The remaining space is defined by each driver as the per-driver
82 * configuration space */
83#define VIRTIO_PCI_CONFIG(dev)		((dev)->msix_enabled ? 24 : 20)
84
85/* Virtio ABI version, this must match exactly */
86#define VIRTIO_PCI_ABI_VERSION		0
87
88/* How many bits to shift physical queue address written to QUEUE_PFN.
89 * 12 is historical, and due to x86 page size. */
90#define VIRTIO_PCI_QUEUE_ADDR_SHIFT	12
91
92/* The alignment to use between consumer and producer parts of vring.
93 * x86 pagesize again. */
94#define VIRTIO_PCI_VRING_ALIGN		4096
95#endif
96