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/** @file
Type and macro definitions corresponding to the virtio-0.9.5 specification.
Copyright (C) 2012, Red Hat, Inc.
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#ifndef _VIRTIO_H_
#define _VIRTIO_H_
#include <Base.h>
//
// Data in the communication area is defined as packed and accessed as
// volatile.
//
// Some structures contain arrays with dynamically determined size. In such
// cases the array and its sibling fields are replaced with pointers.
//
// All indices (variables and fields named *Idx) are free-running and wrap
// around after 0xFFFF. The queue size reported by the host is always an
// integral power of 2, not greater than 32768. Actual array indices are
// consistently calculated by taking the remainder of a given Idx object modulo
// QueueSize. Since 0x10000 is an integral multiple of the QueueSize, UINT16
// wraparound is a correct wraparound modulo QueueSize too (it doesn't offset
// the remainder class).
//
// virtio-0.9.5, 2.3.4 Available Ring
//
#define VRING_AVAIL_F_NO_INTERRUPT BIT0
typedef struct {
volatile UINT16 *Flags;
volatile UINT16 *Idx;
volatile UINT16 *Ring; // QueueSize elements
volatile UINT16 *UsedEvent; // unused as per negotiation
} VRING_AVAIL;
//
// virtio-0.9.5, 2.3.5 Used Ring
//
#define VRING_USED_F_NO_NOTIFY BIT0
#pragma pack(1)
typedef struct {
UINT32 Id;
UINT32 Len;
} VRING_USED_ELEM;
#pragma pack()
typedef struct {
volatile UINT16 *Flags;
volatile UINT16 *Idx;
volatile VRING_USED_ELEM *UsedElem; // QueueSize elements
volatile UINT16 *AvailEvent; // unused as per negotiation
} VRING_USED;
//
// virtio-0.9.5, 2.3.2 Descriptor Table
//
#define VRING_DESC_F_NEXT BIT0 // more descriptors in this request
#define VRING_DESC_F_WRITE BIT1 // buffer to be written *by the host*
#define VRING_DESC_F_INDIRECT BIT2 // unused
#pragma pack(1)
typedef struct {
UINT64 Addr;
UINT32 Len;
UINT16 Flags;
UINT16 Next;
} VRING_DESC;
#pragma pack()
typedef struct {
UINTN NumPages;
VOID *Base; // deallocate only this field
volatile VRING_DESC *Desc; // QueueSize elements
VRING_AVAIL Avail;
VRING_USED Used;
UINT16 QueueSize;
} VRING;
//
// virtio-0.9.5, 2.2.2 Virtio Header -- no MSI-X
// virtio-0.9.5, Appendix D
//
#pragma pack(1)
typedef struct {
UINT32 VhdrDeviceFeatureBits;
UINT32 VhdrGuestFeatureBits;
UINT32 VhdrQueueAddress;
UINT16 VhdrQueueSize;
UINT16 VhdrQueueSelect;
UINT16 VhdrQueueNotify;
UINT8 VhdrDeviceStatus;
UINT8 VhdrISR;
UINT64 VhdrCapacity;
UINT32 VhdrSizeMax;
UINT32 VhdrSegMax;
UINT16 VhdrCylinders;
UINT8 VhdrHeads;
UINT8 VhdrSectors;
UINT32 VhdrBlkSize;
} VBLK_HDR;
#pragma pack()
#define OFFSET_OF_VHDR(Field) OFFSET_OF (VBLK_HDR, Field)
#define SIZE_OF_VHDR(Field) (sizeof ((VBLK_HDR *) 0)->Field)
//
// virtio-0.9.5, 2.2.2.1 Device Status
//
#define VSTAT_ACK BIT0
#define VSTAT_DRIVER BIT1
#define VSTAT_DRIVER_OK BIT2
#define VSTAT_FAILED BIT7
//
// virtio-0.9.5, Appendix B: Reserved (Device-Independent) Feature Bits
//
#define VIRTIO_F_NOTIFY_ON_EMPTY BIT24
#define VIRTIO_F_RING_INDIRECT_DESC BIT28
#define VIRTIO_F_RING_EVENT_IDX BIT29
//
// virtio-0.9.5, Appendix D: Block Device
//
#define VIRTIO_BLK_F_BARRIER BIT0
#define VIRTIO_BLK_F_SIZE_MAX BIT1
#define VIRTIO_BLK_F_SEG_MAX BIT2
#define VIRTIO_BLK_F_GEOMETRY BIT4
#define VIRTIO_BLK_F_RO BIT5
#define VIRTIO_BLK_F_BLK_SIZE BIT6 // treated as "logical block size" in
// practice; actual host side implementation
// negotiates "optimal" block size
// separately
#define VIRTIO_BLK_F_SCSI BIT7
#define VIRTIO_BLK_F_FLUSH BIT9 // identical to "write cache enabled"
//
// We keep the status byte separate from the rest of the virtio-blk request
// header. See description of historical scattering at the end of Appendix D:
// we're going to put the status byte in a separate VRING_DESC.
//
#pragma pack(1)
typedef struct {
UINT32 Type;
UINT32 IoPrio;
UINT64 Sector;
} VIRTIO_BLK_REQ;
#pragma pack()
#define VIRTIO_BLK_T_IN 0x00000000
#define VIRTIO_BLK_T_OUT 0x00000001
#define VIRTIO_BLK_T_SCSI_CMD 0x00000002
#define VIRTIO_BLK_T_SCSI_CMD_OUT 0x00000003
#define VIRTIO_BLK_T_FLUSH 0x00000004
#define VIRTIO_BLK_T_FLUSH_OUT 0x00000005
#define VIRTIO_BLK_T_BARRIER BIT31
#define VIRTIO_BLK_S_OK 0x00
#define VIRTIO_BLK_S_IOERR 0x01
#define VIRTIO_BLK_S_UNSUPP 0x02
#endif // _VIRTIO_H_
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