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author | Daniel De Graaf <dgdegra@tycho.nsa.gov> | 2013-04-11 12:20:25 -0400 |
---|---|---|
committer | Ian Campbell <ian.campbell@citrix.com> | 2013-04-12 14:28:17 +0100 |
commit | f494d9f3c37542435239236085be25c820912304 (patch) | |
tree | 571f23e359f4ba4c78c818ef288147dbd0f563ae /extras/mini-os/tpmfront.c | |
parent | c1f0b214536773630cd5f16bf3d275015373555b (diff) | |
download | xen-f494d9f3c37542435239236085be25c820912304.tar.gz xen-f494d9f3c37542435239236085be25c820912304.tar.bz2 xen-f494d9f3c37542435239236085be25c820912304.zip |
mini-os/tpm{back, front}: Change shared page ABI
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. The vtpm xenbus device now requires a
feature-protocol-v2 node in xenstore to avoid conflicts with existing
(xen-patched) kernels supporting the old interface.
While the contents of the shared page have been defined to allow packets
larger than a single page (actually 4088 bytes) by allowing the client
to add extra grant references, the mapping of these extra references has
not been implemented; a feature node in xenstore may be used in the
future to indicate full support for the multi-page protocol. Most uses
of the TPM should not require this feature.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Jan Beulich <JBeulich@suse.com>
Diffstat (limited to 'extras/mini-os/tpmfront.c')
-rw-r--r-- | extras/mini-os/tpmfront.c | 144 |
1 files changed, 78 insertions, 66 deletions
diff --git a/extras/mini-os/tpmfront.c b/extras/mini-os/tpmfront.c index 0218d7fb84..9f930b5c6f 100644 --- a/extras/mini-os/tpmfront.c +++ b/extras/mini-os/tpmfront.c @@ -47,11 +47,21 @@ void tpmfront_handler(evtchn_port_t port, struct pt_regs *regs, void *data) { struct tpmfront_dev* dev = (struct tpmfront_dev*) data; + vtpm_shared_page_t* shr = dev->page; /*If we get a response when we didnt make a request, just ignore it */ if(!dev->waiting) { return; } + switch (shr->state) { + case VTPM_STATE_FINISH: /* request was completed */ + case VTPM_STATE_IDLE: /* request was cancelled */ + break; + default: + /* Spurious wakeup; do nothing, request is still pending */ + return; + } + dev->waiting = 0; #ifdef HAVE_LIBC if(dev->fd >= 0) { @@ -176,7 +186,7 @@ static int wait_for_backend_state_changed(struct tpmfront_dev* dev, XenbusState ret = wait_for_backend_closed(&events, path); break; default: - break; + TPMFRONT_ERR("Bad wait state %d, ignoring\n", state); } if((err = xenbus_unwatch_path_token(XBT_NIL, path, path))) { @@ -190,13 +200,13 @@ 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 +238,7 @@ 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 +250,6 @@ 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"); @@ -279,6 +288,15 @@ struct tpmfront_dev* init_tpmfront(const char* _nodename) goto error; } + /* Publish protocol v2 feature */ + snprintf(path, 512, "%s/feature-protocol-v2", dev->nodename); + if ((err = xenbus_write(XBT_NIL, path, "1"))) + { + TPMFRONT_ERR("Unable to write feature-protocol-v2 node: %s\n", err); + free(err); + goto error; + } + /* Create and publish grant reference and event channel */ if (tpmfront_connect(dev)) { goto error; @@ -289,18 +307,19 @@ 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) { + /* Ensure backend is also using protocol v2 */ + snprintf(path, 512, "%s/feature-protocol-v2", dev->bepath); + if((err = xenbus_read(XBT_NIL, path, &value))) { + TPMFRONT_ERR("Unable to read %s during tpmfront initialization! error = %s\n", path, err); + free(err); 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; - } + if(strcmp(value, "1")) { + TPMFRONT_ERR("%s has an invalid value (%s)\n", path, value); + free(value); + goto error; } + free(value); TPMFRONT_LOG("Initialization Completed successfully\n"); @@ -314,8 +333,6 @@ void shutdown_tpmfront(struct tpmfront_dev* dev) { char* err; char path[512]; - int i; - tpmif_tx_request_t* tx; if(dev == NULL) { return; } @@ -349,27 +366,12 @@ 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 +389,17 @@ void shutdown_tpmfront(struct tpmfront_dev* dev) int tpmfront_send(struct tpmfront_dev* dev, const uint8_t* msg, size_t length) { + unsigned int offset; + vtpm_shared_page_t* shr = NULL; +#ifdef TPMFRONT_PRINT_DEBUG int i; - tpmif_tx_request_t* tx = NULL; +#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 +413,16 @@ 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 = VTPM_STATE_SUBMIT; + dev->waiting = 1; dev->resplen = 0; #ifdef HAVE_LIBC @@ -429,49 +432,50 @@ int tpmfront_send(struct tpmfront_dev* dev, const uint8_t* msg, size_t length) files[dev->fd].tpmfront.offset = 0; } #endif + wmb(); notify_remote_via_evtchn(dev->evtchn); return 0; } 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; /* Initialize */ *msg = NULL; *length = 0; + 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 (shr->state != VTPM_STATE_FINISH) + goto quit; + + *length = shr->length; + + 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 +508,14 @@ 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) |