FreeBSD/Linux Kernel Cross Reference
sys/xen/interface/io/tpmif.h

     /******************************************************************************
      * tpmif.h
      *
      * TPM I/O interface for Xen guest OSes.
      *
      * Permission is hereby granted, free of charge, to any person obtaining a copy
      * of this software and associated documentation files (the "Software"), to
      * deal in the Software without restriction, including without limitation the
      * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     * sell copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     * DEALINGS IN THE SOFTWARE.
     *
     * Copyright (c) 2005, IBM Corporation
     *
     * Author: Stefan Berger, stefanb@us.ibm.com
     * Grant table support: Mahadevan Gomathisankaran
     *
     * This code has been derived from tools/libxc/xen/io/netif.h
     *
     * Copyright (c) 2003-2004, Keir Fraser
     */
    
    #ifndef __XEN_PUBLIC_IO_TPMIF_H__
    #define __XEN_PUBLIC_IO_TPMIF_H__
    
    #include "../grant_table.h"
    
    struct tpmif_tx_request {
        unsigned long addr;   /* Machine address of packet.   */
        grant_ref_t ref;      /* grant table access reference */
        uint16_t unused;
        uint16_t size;        /* Packet size in bytes.        */
    };
    typedef struct tpmif_tx_request tpmif_tx_request_t;
    
    /*
     * The TPMIF_TX_RING_SIZE defines the number of pages the
     * front-end and backend can exchange (= size of array).
     */
    typedef uint32_t TPMIF_RING_IDX;
    
    #define TPMIF_TX_RING_SIZE 1
    
    /* This structure must fit in a memory page. */
    
    struct tpmif_ring {
        struct tpmif_tx_request req;
    };
    typedef struct tpmif_ring tpmif_ring_t;
    
    struct tpmif_tx_interface {
        struct tpmif_ring ring[TPMIF_TX_RING_SIZE];
    };
    typedef struct tpmif_tx_interface tpmif_tx_interface_t;
    
    /******************************************************************************
     * TPM I/O interface for Xen guest OSes, v2
     *
     * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
     *
     * This protocol emulates the request/response behavior of a TPM using a Xen
     * shared memory interface. All interaction with the TPM is at the direction
     * of the frontend, since a TPM (hardware or virtual) is a passive device -
     * the backend only processes commands as requested by the frontend.
     *
     * The frontend sends a request to the TPM by populating the shared page with
     * the request packet, changing the state to TPMIF_STATE_SUBMIT, and sending
     * and event channel notification. When the backend is finished, it will set
     * the state to TPMIF_STATE_FINISH and send an event channel notification.
     *
     * In order to allow long-running commands to be canceled, the frontend can
     * at any time change the state to TPMIF_STATE_CANCEL and send a notification.
     * The TPM can either finish the command (changing state to TPMIF_STATE_FINISH)
     * or can cancel the command and change the state to TPMIF_STATE_IDLE. The TPM
     * can also change the state to TPMIF_STATE_IDLE instead of TPMIF_STATE_FINISH
     * if another reason for cancellation is required - for example, a physical
     * TPM may cancel a command if the interface is seized by another locality.
     *
     * The TPM command format is defined by the TCG, and is available at
     * http://www.trustedcomputinggroup.org/resources/tpm_main_specification
     */
    
    enum tpmif_state {
        TPMIF_STATE_IDLE,        /* no contents / vTPM idle / cancel complete */
        TPMIF_STATE_SUBMIT,      /* request ready / vTPM working */
        TPMIF_STATE_FINISH,      /* response ready / vTPM idle */
        TPMIF_STATE_CANCEL,      /* cancel requested / vTPM working */
    };
   /* Note: The backend should only change state to IDLE or FINISH, while the
    * frontend should only change to SUBMIT or CANCEL. Status changes do not need
    * to use atomic operations.
    */
   
   
   /* The shared page for vTPM request/response packets looks like:
    *
    *  Offset               Contents
    *  =================================================
    *  0                    struct tpmif_shared_page
    *  16                   [optional] List of grant IDs
    *  16+4*nr_extra_pages  TPM packet data
    *
    * If the TPM packet data extends beyond the end of a single page, the grant IDs
    * defined in extra_pages are used as if they were mapped immediately following
    * the primary shared page. The grants are allocated by the frontend and mapped
    * by the backend. Before sending a request spanning multiple pages, the
    * frontend should verify that the TPM supports such large requests by querying
    * the TPM_CAP_PROP_INPUT_BUFFER property from the TPM.
    */
   struct tpmif_shared_page {
       uint32_t length;         /* request/response length in bytes */
   
       uint8_t state;           /* enum tpmif_state */
       uint8_t locality;        /* for the current request */
       uint8_t pad;             /* should be zero */
   
       uint8_t nr_extra_pages;  /* extra pages for long packets; may be zero */
       uint32_t extra_pages[0]; /* grant IDs; length is actually nr_extra_pages */
   };
   typedef struct tpmif_shared_page tpmif_shared_page_t;
   
   #endif
   
   /*
    * Local variables:
    * mode: C
    * c-file-style: "BSD"
    * c-basic-offset: 4
    * tab-width: 4
    * indent-tabs-mode: nil
    * End:
    */

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