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.
7 * Copyright IBM Corp. 2007
10 * Anthony Liguori <aliguori@us.ibm.com>
12 * This header is BSD licensed so anyone can use the definitions to implement
13 * compatible drivers/servers.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
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
39 #ifndef _LINUX_VIRTIO_PCI_H
40 #define _LINUX_VIRTIO_PCI_H
42 #include <linux/virtio_config.h>
44 /* A 32-bit r/o bitmask of the features supported by the host */
45 #define VIRTIO_PCI_HOST_FEATURES 0
47 /* A 32-bit r/w bitmask of features activated by the guest */
48 #define VIRTIO_PCI_GUEST_FEATURES 4
50 /* A 32-bit r/w PFN for the currently selected queue */
51 #define VIRTIO_PCI_QUEUE_PFN 8
53 /* A 16-bit r/o queue size for the currently selected queue */
54 #define VIRTIO_PCI_QUEUE_NUM 12
56 /* A 16-bit r/w queue selector */
57 #define VIRTIO_PCI_QUEUE_SEL 14
59 /* A 16-bit r/w queue notifier */
60 #define VIRTIO_PCI_QUEUE_NOTIFY 16
62 /* An 8-bit device status register. */
63 #define VIRTIO_PCI_STATUS 18
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
70 /* The bit of the ISR which indicates a device configuration change. */
71 #define VIRTIO_PCI_ISR_CONFIG 0x2
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
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)
85 /* Virtio ABI version, this must match exactly */
86 #define VIRTIO_PCI_ABI_VERSION 0
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
92 /* The alignment to use between consumer and producer parts of vring.
93 * x86 pagesize again. */
94 #define VIRTIO_PCI_VRING_ALIGN 4096
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