Re: [Xen-devel] [PATCH RFC] stubdom: Change vTPM shared page ABI

["Fioravante, Matthew E." <Matthew.Fioravante@xxxxxxxxxx>]

This was something I've been wanting to do for a while so I'm very happy you 
went ahead and fixed it yourself. Once you submit the linux version I'll test 
it on my system.

Acked by: Matthew Fioravante <matthew.fioravante@xxxxxxxxxx>

-----Original Message-----
From: Daniel De Graaf [mailto:dgdegra@xxxxxxxxxxxxx]
Sent: Tuesday, November 20, 2012 11:11 AM
To: Fioravante, Matthew E.
Cc: xen-devel@xxxxxxxxxxxxx; Ian.Campbell@xxxxxxxxxx; Daniel De Graaf
Subject: [PATCH RFC] stubdom: Change vTPM shared page ABI

Since the vTPM implementations are being incorproated into Xen and possibly 
upstream Linux, I would like to see if this protocol change could be added 
before we have significant legacy implementations. If not, I still think it 
would be useful as either a v2 or negotiated protocol change.

The current vTPM protocol is a copy of the network protocol. This was likely 
done for ease of implementation, since support for the network backend/frontend 
existed in Linux and minios. However, this implementation is overly complex 
when dealing with vTPM packets: for example, a vTPM never needs to deal with 
having more than one packet in flight at any given time.

I will send the corresponding patch for the Linux kernel module once I have 
adapted it for the file names used in the upstream version.

------------------------------------>8----------------------------------

This changes the vTPM shared page ABI from a copy of the Xen network interface 
to a single-page interface that better reflects the expected behavior of a TPM: 
only a single request packet can be sent at any given time, and every packet 
sent generates a single response packet. This protocol change should also 
increase efficiency as it avoids mapping and unmapping grants when possible.

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 extras/mini-os/include/tpmback.h  |   1 +
 extras/mini-os/include/tpmfront.h |   7 +-
 extras/mini-os/tpmback.c          | 132 ++++++++++++++-------------------
 extras/mini-os/tpmfront.c         | 150 +++++++++++++++++++-------------------
 xen/include/public/io/tpmif.h     |  45 +++---------
 5 files changed, 148 insertions(+), 187 deletions(-)

diff --git a/extras/mini-os/include/tpmback.h b/extras/mini-os/include/tpmback.h
index ff86732..ec9eda4 100644
--- a/extras/mini-os/include/tpmback.h
+++ b/extras/mini-os/include/tpmback.h
@@ -43,6 +43,7 @@

 struct tpmcmd {
    domid_t domid;              /* Domid of the frontend */
+   uint8_t locality;    /* Locality requested by the frontend */
    unsigned int handle;        /* Handle of the frontend */
    unsigned char uuid[16];                     /* uuid of the tpm interface */

diff --git a/extras/mini-os/include/tpmfront.h 
b/extras/mini-os/include/tpmfront.h
index fd2cb17..a0c7c4d 100644
--- a/extras/mini-os/include/tpmfront.h
+++ b/extras/mini-os/include/tpmfront.h
@@ -37,9 +37,7 @@ struct tpmfront_dev {
    grant_ref_t ring_ref;
    evtchn_port_t evtchn;

-   tpmif_tx_interface_t* tx;
-
-   void** pages;
+   vtpm_shared_page_t *page;

    domid_t bedomid;
    char* nodename;
@@ -77,6 +75,9 @@ void shutdown_tpmfront(struct tpmfront_dev* dev);
  * */
 int tpmfront_cmd(struct tpmfront_dev* dev, uint8_t* req, size_t reqlen, 
uint8_t** resp, size_t* resplen);

+/* Set the locality used for communicating with a vTPM */ int
+tpmfront_set_locality(struct tpmfront_dev* dev, int locality);
+
 #ifdef HAVE_LIBC
 #include <sys/stat.h>
 /* POSIX IO functions:
diff --git a/extras/mini-os/tpmback.c b/extras/mini-os/tpmback.c index 
658fed1..29aced9 100644
--- a/extras/mini-os/tpmback.c
+++ b/extras/mini-os/tpmback.c
@@ -86,10 +86,7 @@ struct tpmif {
    evtchn_port_t evtchn;

    /* Shared page */
-   tpmif_tx_interface_t* tx;
-
-   /* pointer to TPMIF_RX_RING_SIZE pages */
-   void** pages;
+   vtpm_shared_page_t *page;

    enum xenbus_state state;
    enum { DISCONNECTED, DISCONNECTING, CONNECTED } status; @@ -386,8 +383,7 @@ 
inline tpmif_t* __init_tpmif(domid_t domid, unsigned int handle)
    tpmif->fe_state_path = NULL;
    tpmif->state = XenbusStateInitialising;
    tpmif->status = DISCONNECTED;
-   tpmif->tx = NULL;
-   tpmif->pages = NULL;
+   tpmif->page = NULL;
    tpmif->flags = 0;
    memset(tpmif->uuid, 0, sizeof(tpmif->uuid));
    return tpmif;
@@ -395,9 +391,6 @@ inline tpmif_t* __init_tpmif(domid_t domid, unsigned int 
handle)

 void __free_tpmif(tpmif_t* tpmif)
 {
-   if(tpmif->pages) {
-      free(tpmif->pages);
-   }
    if(tpmif->fe_path) {
       free(tpmif->fe_path);
    }
@@ -430,12 +423,6 @@ tpmif_t* new_tpmif(domid_t domid, unsigned int handle)
       goto error;
    }

-   /* allocate pages to be used for shared mapping */
-   if((tpmif->pages = malloc(sizeof(void*) * TPMIF_TX_RING_SIZE)) == NULL) {
-      goto error;
-   }
-   memset(tpmif->pages, 0, sizeof(void*) * TPMIF_TX_RING_SIZE);
-
    if(tpmif_change_state(tpmif, XenbusStateInitWait)) {
       goto error;
    }
@@ -486,7 +473,7 @@ void free_tpmif(tpmif_t* tpmif)
       tpmif->status = DISCONNECTING;
       mask_evtchn(tpmif->evtchn);

-      if(gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->tx, 1)) {
+      if(gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->page, 1)) {
         TPMBACK_ERR("%u/%u Error occured while trying to unmap shared page\n", 
(unsigned int) tpmif->domid, tpmif->handle);
       }

@@ -529,9 +516,10 @@ void free_tpmif(tpmif_t* tpmif)  void 
tpmback_handler(evtchn_port_t port, struct pt_regs *regs, void *data)  {
    tpmif_t* tpmif = (tpmif_t*) data;
-   tpmif_tx_request_t* tx = &tpmif->tx->ring[0].req;
-   /* Throw away 0 size events, these can trigger from event channel unmasking 
*/
-   if(tx->size == 0)
+   vtpm_shared_page_t* pg = tpmif->page;
+
+   /* Only pay attention if the request is ready */
+   if (pg->state == 0)
       return;

    TPMBACK_DEBUG("EVENT CHANNEL FIRE %u/%u\n", (unsigned int) tpmif->domid, 
tpmif->handle); @@ -585,11 +573,10 @@ int connect_fe(tpmif_t* tpmif)
    free(value);

    domid = tpmif->domid;
-   if((tpmif->tx = gntmap_map_grant_refs(&gtpmdev.map, 1, &domid, 0, &ringref, 
PROT_READ | PROT_WRITE)) == NULL) {
+   if((tpmif->page = gntmap_map_grant_refs(&gtpmdev.map, 1, &domid, 0,
+ &ringref, PROT_READ | PROT_WRITE)) == NULL) {
       TPMBACK_ERR("Failed to map grant reference %u/%u\n", (unsigned int) 
tpmif->domid, tpmif->handle);
       return -1;
    }
-   memset(tpmif->tx, 0, PAGE_SIZE);

    /*Bind the event channel */
    if((evtchn_bind_interdomain(tpmif->domid, evtchn, tpmback_handler, tpmif, 
&tpmif->evtchn))) @@ -618,10 +605,28 @@ error_post_evtchn:
    mask_evtchn(tpmif->evtchn);
    unbind_evtchn(tpmif->evtchn);
 error_post_map:
-   gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->tx, 1);
+   gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->page, 1);
    return -1;
 }

+static void disconnect_fe(tpmif_t* tpmif) {
+   if (tpmif->status == CONNECTED) {
+      tpmif->status = DISCONNECTING;
+      mask_evtchn(tpmif->evtchn);
+
+      if(gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->page, 1)) {
+        TPMBACK_ERR("%u/%u Error occured while trying to unmap shared page\n", 
(unsigned int) tpmif->domid, tpmif->handle);
+      }
+
+      unbind_evtchn(tpmif->evtchn);
+   }
+   tpmif->status = DISCONNECTED;
+   tpmif_change_state(tpmif, XenbusStateReconfigured);
+
+   TPMBACK_LOG("Frontend %u/%u disconnected\n", (unsigned int)
+tpmif->domid, tpmif->handle); }
+
 static int frontend_changed(tpmif_t* tpmif)  {
    int state = xenbus_read_integer(tpmif->fe_state_path);
@@ -874,6 +879,7 @@ void shutdown_tpmback(void)  inline void 
init_tpmcmd(tpmcmd_t* tpmcmd, domid_t domid, unsigned int handle, unsigned char 
uuid[16])  {
    tpmcmd->domid = domid;
+   tpmcmd->locality = -1;
    tpmcmd->handle = handle;
    memcpy(tpmcmd->uuid, uuid, sizeof(tpmcmd->uuid));
    tpmcmd->req = NULL;
@@ -884,12 +890,12 @@ inline void init_tpmcmd(tpmcmd_t* tpmcmd, domid_t domid, 
unsigned int handle, un

 tpmcmd_t* get_request(tpmif_t* tpmif) {
    tpmcmd_t* cmd;
-   tpmif_tx_request_t* tx;
-   int offset;
-   int tocopy;
-   int i;
-   uint32_t domid;
+   vtpm_shared_page_t* shr;
+   unsigned int offset;
    int flags;
+#ifdef TPMBACK_PRINT_DEBUG
+int i;
+#endif

    local_irq_save(flags);

@@ -899,35 +905,22 @@ tpmcmd_t* get_request(tpmif_t* tpmif) {
    }
    init_tpmcmd(cmd, tpmif->domid, tpmif->handle, tpmif->uuid);

-   tx = &tpmif->tx->ring[0].req;
-   cmd->req_len = tx->size;
+   shr = tpmif->page;
+   cmd->req_len = shr->length;
+   cmd->locality = shr->locality;
+   offset = sizeof(*shr) + 4*shr->nr_extra_pages;
+   if (offset > PAGE_SIZE || offset + cmd->req_len > PAGE_SIZE) {
+      TPMBACK_ERR("%u/%u Command size too long for shared page!\n", (unsigned 
int) tpmif->domid, tpmif->handle);
+      goto error;
+   }
    /* Allocate the buffer */
    if(cmd->req_len) {
       if((cmd->req = malloc(cmd->req_len)) == NULL) {
         goto error;
       }
    }
-   /* Copy the bits from the shared pages */
-   offset = 0;
-   for(i = 0; i < TPMIF_TX_RING_SIZE && offset < cmd->req_len; ++i) {
-      tx = &tpmif->tx->ring[i].req;
-
-      /* Map the page with the data */
-      domid = (uint32_t)tpmif->domid;
-      if((tpmif->pages[i] = gntmap_map_grant_refs(&gtpmdev.map, 1, &domid, 0, 
&tx->ref, PROT_READ)) == NULL) {
-        TPMBACK_ERR("%u/%u Unable to map shared page during read!\n", 
(unsigned int) tpmif->domid, tpmif->handle);
-        goto error;
-      }
-
-      /* do the copy now */
-      tocopy = min(cmd->req_len - offset, PAGE_SIZE);
-      memcpy(&cmd->req[offset], tpmif->pages[i], tocopy);
-      offset += tocopy;
-
-      /* release the page */
-      gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->pages[i], 1);
-
-   }
+   /* Copy the bits from the shared page(s) */
+   memcpy(cmd->req, offset + (uint8_t*)shr, cmd->req_len);

 #ifdef TPMBACK_PRINT_DEBUG
    TPMBACK_DEBUG("Received Tpm Command from %u/%u of size %u", (unsigned int) 
tpmif->domid, tpmif->handle, cmd->req_len); @@ -958,38 +951,24 @@ error:

 void send_response(tpmcmd_t* cmd, tpmif_t* tpmif)  {
-   tpmif_tx_request_t* tx;
-   int offset;
-   int i;
-   uint32_t domid;
-   int tocopy;
+   vtpm_shared_page_t* shr;
+   unsigned int offset;
    int flags;
+#ifdef TPMBACK_PRINT_DEBUG
+int i;
+#endif

    local_irq_save(flags);

-   tx = &tpmif->tx->ring[0].req;
-   tx->size = cmd->resp_len;
-
-   offset = 0;
-   for(i = 0; i < TPMIF_TX_RING_SIZE && offset < cmd->resp_len; ++i) {
-      tx = &tpmif->tx->ring[i].req;
-
-      /* Map the page with the data */
-      domid = (uint32_t)tpmif->domid;
-      if((tpmif->pages[i] = gntmap_map_grant_refs(&gtpmdev.map, 1, &domid, 0, 
&tx->ref, PROT_WRITE)) == NULL) {
-        TPMBACK_ERR("%u/%u Unable to map shared page during write!\n", 
(unsigned int) tpmif->domid, tpmif->handle);
-        goto error;
-      }
-
-      /* do the copy now */
-      tocopy = min(cmd->resp_len - offset, PAGE_SIZE);
-      memcpy(tpmif->pages[i], &cmd->resp[offset], tocopy);
-      offset += tocopy;
-
-      /* release the page */
-      gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->pages[i], 1);
+   shr = tpmif->page;
+   shr->length = cmd->resp_len;

+   offset = sizeof(*shr) + 4*shr->nr_extra_pages;
+   if (offset > PAGE_SIZE || offset + cmd->resp_len > PAGE_SIZE) {
+      TPMBACK_ERR("%u/%u Command size too long for shared page!\n", (unsigned 
int) tpmif->domid, tpmif->handle);
+      goto error;
    }
+   memcpy(offset + (uint8_t*)shr, cmd->resp, cmd->resp_len);

 #ifdef TPMBACK_PRINT_DEBUG
    TPMBACK_DEBUG("Sent response to %u/%u of size %u", (unsigned int) 
tpmif->domid, tpmif->handle, cmd->resp_len); @@ -1003,6 +982,7 @@ void 
send_response(tpmcmd_t* cmd, tpmif_t* tpmif)  #endif
    /* clear the ready flag and send the event channel notice to the frontend */
    tpmif_req_finished(tpmif);
+   shr->state = 0;
    notify_remote_via_evtchn(tpmif->evtchn);
 error:
    local_irq_restore(flags);
diff --git a/extras/mini-os/tpmfront.c b/extras/mini-os/tpmfront.c index 
0218d7f..bcee93d 100644
--- a/extras/mini-os/tpmfront.c
+++ b/extras/mini-os/tpmfront.c
@@ -153,6 +153,32 @@ static int wait_for_backend_closed(xenbus_event_queue* 
events, char* path)

 }

+static int wait_for_backend_reconfig(xenbus_event_queue* events, char*
+path) {
+   int state;
+
+   TPMFRONT_LOG("Waiting for backend to reconfigure...\n");
+   while(1) {
+      state = xenbus_read_integer(path);
+      if ( state < 0)
+        state = XenbusStateUnknown;
+      switch(state) {
+        case XenbusStateUnknown:
+           TPMFRONT_ERR("Backend Unknown state, forcing shutdown\n");
+           return -1;
+        case XenbusStateClosed:
+           TPMFRONT_LOG("Backend Closed\n");
+           return 0;
+        case XenbusStateReconfigured:
+           TPMFRONT_LOG("Backend Reconfigured\n");
+           return 0;
+        default:
+           xenbus_wait_for_watch(events);
+      }
+   }
+
+}
+
 static int wait_for_backend_state_changed(struct tpmfront_dev* dev, 
XenbusState state) {
    char* err;
    int ret = 0;
@@ -175,8 +201,11 @@ static int wait_for_backend_state_changed(struct 
tpmfront_dev* dev, XenbusState
       case XenbusStateClosed:
         ret = wait_for_backend_closed(&events, path);
         break;
-      default:
+      case XenbusStateReconfigured:
+        ret = wait_for_backend_reconfig(&events, path);
         break;
+      default:
+         TPMFRONT_ERR("Bad wait state %d, ignoring\n", state);
    }

    if((err = xenbus_unwatch_path_token(XBT_NIL, path, path))) { @@ -190,13 
+219,13 @@ static int tpmfront_connect(struct tpmfront_dev* dev)  {
    char* err;
    /* Create shared page */
-   dev->tx = (tpmif_tx_interface_t*) alloc_page();
-   if(dev->tx == NULL) {
+   dev->page = (vtpm_shared_page_t*) alloc_page();
+   if(dev->page == NULL) {
       TPMFRONT_ERR("Unable to allocate page for shared memory\n");
       goto error;
    }
-   memset(dev->tx, 0, PAGE_SIZE);
-   dev->ring_ref = gnttab_grant_access(dev->bedomid, virt_to_mfn(dev->tx), 0);
+   memset(dev->page, 0, PAGE_SIZE);
+   dev->ring_ref = gnttab_grant_access(dev->bedomid,
+ virt_to_mfn(dev->page), 0);
    TPMFRONT_DEBUG("grant ref is %lu\n", (unsigned long) dev->ring_ref);

    /*Create event channel */
@@ -228,7 +257,7 @@ error_postevtchn:
       unbind_evtchn(dev->evtchn);
 error_postmap:
       gnttab_end_access(dev->ring_ref);
-      free_page(dev->tx);
+      free_page(dev->page);
 error:
    return -1;
 }
@@ -240,7 +269,6 @@ struct tpmfront_dev* init_tpmfront(const char* _nodename)
    char path[512];
    char* value, *err;
    unsigned long long ival;
-   int i;

    printk("============= Init TPM Front ================\n");

@@ -289,19 +317,6 @@ struct tpmfront_dev* init_tpmfront(const char* _nodename)
       goto error;
    }

-   /* Allocate pages that will contain the messages */
-   dev->pages = malloc(sizeof(void*) * TPMIF_TX_RING_SIZE);
-   if(dev->pages == NULL) {
-      goto error;
-   }
-   memset(dev->pages, 0, sizeof(void*) * TPMIF_TX_RING_SIZE);
-   for(i = 0; i < TPMIF_TX_RING_SIZE; ++i) {
-      dev->pages[i] = (void*)alloc_page();
-      if(dev->pages[i] == NULL) {
-        goto error;
-      }
-   }
-
    TPMFRONT_LOG("Initialization Completed successfully\n");

    return dev;
@@ -314,12 +329,10 @@ void shutdown_tpmfront(struct tpmfront_dev* dev)  {
    char* err;
    char path[512];
-   int i;
-   tpmif_tx_request_t* tx;
    if(dev == NULL) {
       return;
    }
-   TPMFRONT_LOG("Shutting down tpmfront\n");
+   TPMFRONT_LOG("Shutting down tpmfront%s\n", for_reconfig ? " for
+ reconfigure" : "");
    /* disconnect */
    if(dev->state == XenbusStateConnected) {
       dev->state = XenbusStateClosing;
@@ -349,27 +362,12 @@ void shutdown_tpmfront(struct tpmfront_dev* dev)
       /* Wait for the backend to close and unmap shared pages, ignore any 
errors */
       wait_for_backend_state_changed(dev, XenbusStateClosed);

-      /* Cleanup any shared pages */
-      if(dev->pages) {
-        for(i = 0; i < TPMIF_TX_RING_SIZE; ++i) {
-           if(dev->pages[i]) {
-              tx = &dev->tx->ring[i].req;
-              if(tx->ref != 0) {
-                 gnttab_end_access(tx->ref);
-              }
-              free_page(dev->pages[i]);
-           }
-        }
-        free(dev->pages);
-      }
-
       /* Close event channel and unmap shared page */
       mask_evtchn(dev->evtchn);
       unbind_evtchn(dev->evtchn);
       gnttab_end_access(dev->ring_ref);

-      free_page(dev->tx);
-
+      free_page(dev->page);
    }

    /* Cleanup memory usage */
@@ -387,13 +385,17 @@ void shutdown_tpmfront(struct tpmfront_dev* dev)

 int tpmfront_send(struct tpmfront_dev* dev, const uint8_t* msg, size_t length) 
 {
-   int i;
-   tpmif_tx_request_t* tx = NULL;
+   unsigned int offset;
+   vtpm_shared_page_t* shr = NULL;
+#ifdef TPMFRONT_PRINT_DEBUG
+int i;
+#endif
    /* Error Checking */
    if(dev == NULL || dev->state != XenbusStateConnected) {
       TPMFRONT_ERR("Tried to send message through disconnected frontend\n");
       return -1;
    }
+   shr = dev->page;

 #ifdef TPMFRONT_PRINT_DEBUG
    TPMFRONT_DEBUG("Sending Msg to backend size=%u", (unsigned int) length); @@ 
-407,19 +409,16 @@ int tpmfront_send(struct tpmfront_dev* dev, const uint8_t* 
msg, size_t length)  #endif

    /* Copy to shared pages now */
-   for(i = 0; length > 0 && i < TPMIF_TX_RING_SIZE; ++i) {
-      /* Share the page */
-      tx = &dev->tx->ring[i].req;
-      tx->unused = 0;
-      tx->addr = virt_to_mach(dev->pages[i]);
-      tx->ref = gnttab_grant_access(dev->bedomid, virt_to_mfn(dev->pages[i]), 
0);
-      /* Copy the bits to the page */
-      tx->size = length > PAGE_SIZE ? PAGE_SIZE : length;
-      memcpy(dev->pages[i], &msg[i * PAGE_SIZE], tx->size);
-
-      /* Update counters */
-      length -= tx->size;
+   offset = sizeof(*shr);
+   if (length + offset > PAGE_SIZE) {
+      TPMFRONT_ERR("Message too long for shared page\n");
+      return -1;
    }
+   memcpy(offset + (uint8_t*)shr, msg, length);
+   shr->length = length;
+   barrier();
+   shr->state = 1;
+
    dev->waiting = 1;
    dev->resplen = 0;
 #ifdef HAVE_LIBC
@@ -434,44 +433,41 @@ int tpmfront_send(struct tpmfront_dev* dev, const 
uint8_t* msg, size_t length)  }  int tpmfront_recv(struct tpmfront_dev* dev, 
uint8_t** msg, size_t *length)  {
-   tpmif_tx_request_t* tx;
-   int i;
+   unsigned int offset;
+   vtpm_shared_page_t* shr = NULL;
+#ifdef TPMFRONT_PRINT_DEBUG
+int i;
+#endif
    if(dev == NULL || dev->state != XenbusStateConnected) {
       TPMFRONT_ERR("Tried to receive message from disconnected frontend\n");
       return -1;
    }
    /*Wait for the response */
    wait_event(dev->waitq, (!dev->waiting));
+   shr = dev->page;
+   if (shr->state != 0)
+      goto quit;

    /* Initialize */
    *msg = NULL;
-   *length = 0;
+   *length = shr->length;
+   offset = sizeof(*shr);

-   /* special case, just quit */
-   tx = &dev->tx->ring[0].req;
-   if(tx->size == 0 ) {
-       goto quit;
-   }
-   /* Get the total size */
-   tx = &dev->tx->ring[0].req;
-   for(i = 0; i < TPMIF_TX_RING_SIZE && tx->size > 0; ++i) {
-      tx = &dev->tx->ring[i].req;
-      *length += tx->size;
+   if (*length + offset > PAGE_SIZE) {
+      TPMFRONT_ERR("Reply too long for shared page\n");
+      return -1;
    }
+
    /* Alloc the buffer */
    if(dev->respbuf) {
       free(dev->respbuf);
    }
    *msg = dev->respbuf = malloc(*length);
    dev->resplen = *length;
+
    /* Copy the bits */
-   tx = &dev->tx->ring[0].req;
-   for(i = 0; i < TPMIF_TX_RING_SIZE && tx->size > 0; ++i) {
-      tx = &dev->tx->ring[i].req;
-      memcpy(&(*msg)[i * PAGE_SIZE], dev->pages[i], tx->size);
-      gnttab_end_access(tx->ref);
-      tx->ref = 0;
-   }
+   memcpy(*msg, offset + (uint8_t*)shr, *length);
+
 #ifdef TPMFRONT_PRINT_DEBUG
    TPMFRONT_DEBUG("Received response from backend size=%u", (unsigned int) 
*length);
    for(i = 0; i < *length; ++i) {
@@ -504,6 +500,14 @@ int tpmfront_cmd(struct tpmfront_dev* dev, uint8_t* req, 
size_t reqlen, uint8_t*
    return 0;
 }

+int tpmfront_set_locality(struct tpmfront_dev* dev, int locality) {
+   if (!dev || !dev->page)
+      return -1;
+   dev->page->locality = locality;
+   return 0;
+}
+
 #ifdef HAVE_LIBC
 #include <errno.h>
 int tpmfront_open(struct tpmfront_dev* dev) diff --git 
a/xen/include/public/io/tpmif.h b/xen/include/public/io/tpmif.h index 
02ccdab..afc9181 100644
--- a/xen/include/public/io/tpmif.h
+++ b/xen/include/public/io/tpmif.h
@@ -1,7 +1,7 @@
 /******************************************************************************
  * tpmif.h
  *
- * TPM I/O interface for Xen guest OSes.
+ * TPM I/O interface for Xen guest OSes, v2
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to @@ 
-21,48 +21,23 @@
  * 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@xxxxxxxxxx
- * 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 vtpm_shared_page {
+    uint16_t length;         /* request/response length in bytes */

-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;
+    uint8_t state;           /* 0 - response ready / idle
+                              * 1 - request ready / working */
+    uint8_t locality;        /* for the current request */
+    uint8_t padding[3];

-struct tpmif_tx_interface {
-    struct tpmif_ring ring[TPMIF_TX_RING_SIZE];
+    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_tx_interface tpmif_tx_interface_t;
+typedef struct vtpm_shared_page vtpm_shared_page_t;

 #endif

--
1.7.11.7


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