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