/* SPDX-License-Identifier: MIT */ /****************************************************************************** * tpmif.h * * TPM I/O interface for Xen guest OSes. * * 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: */