include/xen/interface/io/tpmif.h

   1 /******************************************************************************
   2  * tpmif.h
   3  *
   4  * TPM I/O interface for Xen guest OSes, v2
   5  *
   6  * This file is in the public domain.
   7  *
   8  */
   9
  10 #ifndef __XEN_PUBLIC_IO_TPMIF_H__
  11 #define __XEN_PUBLIC_IO_TPMIF_H__
  12
  13 /*
  14  * Xenbus state machine
  15  *
  16  * Device open:
  17  *   1. Both ends start in XenbusStateInitialising
  18  *   2. Backend transitions to InitWait (frontend does not wait on this step)
  19  *   3. Frontend populates ring-ref, event-channel, feature-protocol-v2
  20  *   4. Frontend transitions to Initialised
  21  *   5. Backend maps grant and event channel, verifies feature-protocol-v2
  22  *   6. Backend transitions to Connected
  23  *   7. Frontend verifies feature-protocol-v2, transitions to Connected
  24  *
  25  * Device close:
  26  *   1. State is changed to XenbusStateClosing
  27  *   2. Frontend transitions to Closed
  28  *   3. Backend unmaps grant and event, changes state to InitWait
  29  */
  30
  31 enum vtpm_shared_page_state {
  32         VTPM_STATE_IDLE,         /* no contents / vTPM idle / cancel complete */
  33         VTPM_STATE_SUBMIT,       /* request ready / vTPM working */
  34         VTPM_STATE_FINISH,       /* response ready / vTPM idle */
  35         VTPM_STATE_CANCEL,       /* cancel requested / vTPM working */
  36 };
  37 /* The backend should only change state to IDLE or FINISH, while the
  38  * frontend should only change to SUBMIT or CANCEL. */
  39
  40
  41 struct vtpm_shared_page {
  42         uint32_t length;         /* request/response length in bytes */
  43
  44         uint8_t state;           /* enum vtpm_shared_page_state */
  45         uint8_t locality;        /* for the current request */
  46         uint8_t pad;
  47
  48         uint8_t nr_extra_pages;  /* extra pages for long packets; may be zero */
  49         uint32_t extra_pages[0]; /* grant IDs; length in nr_extra_pages */
  50 };
  51
  52 #endif