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 39 struct 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 }; 45 typedef 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 */ 51 typedef uint32_t TPMIF_RING_IDX; 52 53 #define TPMIF_TX_RING_SIZE 1 54 55 /* This structure must fit in a memory page. */ 56 57 struct tpmif_ring { 58 struct tpmif_tx_request req; 59 }; 60 typedef struct tpmif_ring tpmif_ring_t; 61 62 struct tpmif_tx_interface { 63 struct tpmif_ring ring[TPMIF_TX_RING_SIZE]; 64 }; 65 typedef 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 94 enum 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 */ 121 struct 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 }; 131 typedef 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