text: /*
   * Virtio PCI driver
   *
   * This module allows virtio devices to be used over a virtual PCI device.
   * This can be used with QEMU based VMMs like KVM or Xen.
   *
   * Copyright IBM Corp. 2007
   *
   * Authors:
   *  Anthony Liguori  <aliguori@us.ibm.com>
   *
   * This header is BSD licensed so anyone can use the definitions to implement
   * compatible drivers/servers.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of IBM nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #ifndef _LINUX_VIRTIO_PCI_H
  #define _LINUX_VIRTIO_PCI_H
  
  #include <linux/virtio_config.h>
  
  #ifndef VIRTIO_PCI_NO_LEGACY
  
  /* A 32-bit r/o bitmask of the features supported by the host */
  #define VIRTIO_PCI_HOST_FEATURES	0
  
  /* A 32-bit r/w bitmask of features activated by the guest */
  #define VIRTIO_PCI_GUEST_FEATURES	4
  
  /* A 32-bit r/w PFN for the currently selected queue */
  #define VIRTIO_PCI_QUEUE_PFN		8
  
  /* A 16-bit r/o queue size for the currently selected queue */
  #define VIRTIO_PCI_QUEUE_NUM		12
  
  /* A 16-bit r/w queue selector */
  #define VIRTIO_PCI_QUEUE_SEL		14
  
  /* A 16-bit r/w queue notifier */
  #define VIRTIO_PCI_QUEUE_NOTIFY		16
  
  /* An 8-bit device status register.  */
  #define VIRTIO_PCI_STATUS		18
  
  /* An 8-bit r/o interrupt status register.  Reading the value will return the
   * current contents of the ISR and will also clear it.  This is effectively
   * a read-and-acknowledge. */
  #define VIRTIO_PCI_ISR			19
  
  /* MSI-X registers: only enabled if MSI-X is enabled. */
  /* A 16-bit vector for configuration changes. */
  #define VIRTIO_MSI_CONFIG_VECTOR        20
  /* A 16-bit vector for selected queue notifications. */
  #define VIRTIO_MSI_QUEUE_VECTOR         22
  
  /* The remaining space is defined by each driver as the per-driver
   * configuration space */
  #define VIRTIO_PCI_CONFIG_OFF(msix_enabled)	((msix_enabled) ? 24 : 20)
  /* Deprecated: please use VIRTIO_PCI_CONFIG_OFF instead */
  #define VIRTIO_PCI_CONFIG(dev)	VIRTIO_PCI_CONFIG_OFF((dev)->msix_enabled)
  
  /* Virtio ABI version, this must match exactly */
  #define VIRTIO_PCI_ABI_VERSION		0
  
  /* How many bits to shift physical queue address written to QUEUE_PFN.
   * 12 is historical, and due to x86 page size. */
  #define VIRTIO_PCI_QUEUE_ADDR_SHIFT	12
  
  /* The alignment to use between consumer and producer parts of vring.
   * x86 pagesize again. */
  #define VIRTIO_PCI_VRING_ALIGN		4096
  
  #endif /* VIRTIO_PCI_NO_LEGACY */
  
  /* The bit of the ISR which indicates a device configuration change. */
  #define VIRTIO_PCI_ISR_CONFIG		0x2
  /* Vector value used to disable MSI for queue */
  #define VIRTIO_MSI_NO_VECTOR            0xffff
  
  #endif
  