1/******************************************************************************
2 * tpmif.h
3 *
4 * TPM I/O interface for Xen guest OSes.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (c) 2005, IBM Corporation
25 *
26 * Author: Stefan Berger, stefanb@us.ibm.com
27 * Grant table support: Mahadevan Gomathisankaran
28 *
29 * This code has been derived from tools/libxc/xen/io/netif.h
30 *
31 * Copyright (c) 2003-2004, Keir Fraser
32 */
33
34#ifndef __XEN_PUBLIC_IO_TPMIF_H__
35#define __XEN_PUBLIC_IO_TPMIF_H__
36
37#include "../grant_table.h"
38
39struct tpmif_tx_request {
40    unsigned long addr;   /* Machine address of packet.   */
41    grant_ref_t ref;      /* grant table access reference */
42    uint16_t unused;
43    uint16_t size;        /* Packet size in bytes.        */
44};
45typedef struct tpmif_tx_request tpmif_tx_request_t;
46
47/*
48 * The TPMIF_TX_RING_SIZE defines the number of pages the
49 * front-end and backend can exchange (= size of array).
50 */
51typedef uint32_t TPMIF_RING_IDX;
52
53#define TPMIF_TX_RING_SIZE 1
54
55/* This structure must fit in a memory page. */
56
57struct tpmif_ring {
58    struct tpmif_tx_request req;
59};
60typedef struct tpmif_ring tpmif_ring_t;
61
62struct tpmif_tx_interface {
63    struct tpmif_ring ring[TPMIF_TX_RING_SIZE];
64};
65typedef struct tpmif_tx_interface tpmif_tx_interface_t;
66
67/******************************************************************************
68 * TPM I/O interface for Xen guest OSes, v2
69 *
70 * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
71 *
72 * This protocol emulates the request/response behavior of a TPM using a Xen
73 * shared memory interface. All interaction with the TPM is at the direction
74 * of the frontend, since a TPM (hardware or virtual) is a passive device -
75 * the backend only processes commands as requested by the frontend.
76 *
77 * The frontend sends a request to the TPM by populating the shared page with
78 * the request packet, changing the state to TPMIF_STATE_SUBMIT, and sending
79 * and event channel notification. When the backend is finished, it will set
80 * the state to TPMIF_STATE_FINISH and send an event channel notification.
81 *
82 * In order to allow long-running commands to be canceled, the frontend can
83 * at any time change the state to TPMIF_STATE_CANCEL and send a notification.
84 * The TPM can either finish the command (changing state to TPMIF_STATE_FINISH)
85 * or can cancel the command and change the state to TPMIF_STATE_IDLE. The TPM
86 * can also change the state to TPMIF_STATE_IDLE instead of TPMIF_STATE_FINISH
87 * if another reason for cancellation is required - for example, a physical
88 * TPM may cancel a command if the interface is seized by another locality.
89 *
90 * The TPM command format is defined by the TCG, and is available at
91 * http://www.trustedcomputinggroup.org/resources/tpm_main_specification
92 */
93
94enum tpmif_state {
95    TPMIF_STATE_IDLE,        /* no contents / vTPM idle / cancel complete */
96    TPMIF_STATE_SUBMIT,      /* request ready / vTPM working */
97    TPMIF_STATE_FINISH,      /* response ready / vTPM idle */
98    TPMIF_STATE_CANCEL,      /* cancel requested / vTPM working */
99};
100/* Note: The backend should only change state to IDLE or FINISH, while the
101 * frontend should only change to SUBMIT or CANCEL. Status changes do not need
102 * to use atomic operations.
103 */
104
105
106/* The shared page for vTPM request/response packets looks like:
107 *
108 *  Offset               Contents
109 *  =================================================
110 *  0                    struct tpmif_shared_page
111 *  16                   [optional] List of grant IDs
112 *  16+4*nr_extra_pages  TPM packet data
113 *
114 * If the TPM packet data extends beyond the end of a single page, the grant IDs
115 * defined in extra_pages are used as if they were mapped immediately following
116 * the primary shared page. The grants are allocated by the frontend and mapped
117 * by the backend. Before sending a request spanning multiple pages, the
118 * frontend should verify that the TPM supports such large requests by querying
119 * the TPM_CAP_PROP_INPUT_BUFFER property from the TPM.
120 */
121struct tpmif_shared_page {
122    uint32_t length;         /* request/response length in bytes */
123
124    uint8_t state;           /* enum tpmif_state */
125    uint8_t locality;        /* for the current request */
126    uint8_t pad;             /* should be zero */
127
128    uint8_t nr_extra_pages;  /* extra pages for long packets; may be zero */
129    uint32_t extra_pages[0]; /* grant IDs; length is actually nr_extra_pages */
130};
131typedef struct tpmif_shared_page tpmif_shared_page_t;
132
133#endif
134
135/*
136 * Local variables:
137 * mode: C
138 * c-file-style: "BSD"
139 * c-basic-offset: 4
140 * tab-width: 4
141 * indent-tabs-mode: nil
142 * End:
143 */
144