include/linux/virtio_pci.h

   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