[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] drivers/tpm-xen: Change vTPM 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. Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> --- drivers/char/tpm/xen-tpmfront_if.c | 191 ++++++------------------------------- include/xen/interface/io/tpmif.h | 42 ++------ 2 files changed, 40 insertions(+), 193 deletions(-) diff --git a/drivers/char/tpm/xen-tpmfront_if.c b/drivers/char/tpm/xen-tpmfront_if.c index ba7fad8..02405af 100644 --- a/drivers/char/tpm/xen-tpmfront_if.c +++ b/drivers/char/tpm/xen-tpmfront_if.c @@ -53,7 +53,7 @@ struct tpm_private { struct tpm_chip *chip; - struct tpmif_tx_interface *tx; + struct vtpm_shared_page *page; atomic_t refcnt; unsigned int evtchn; u8 is_connected; @@ -61,8 +61,6 @@ struct tpm_private { spinlock_t tx_lock; - struct tx_buffer *tx_buffers[TPMIF_TX_RING_SIZE]; - atomic_t tx_busy; void *tx_remember; @@ -73,15 +71,7 @@ struct tpm_private { int ring_ref; }; -struct tx_buffer { - unsigned int size; /* available space in data */ - unsigned int len; /* used space in data */ - unsigned char *data; /* pointer to a page */ -}; - - /* locally visible variables */ -static grant_ref_t gref_head; static struct tpm_private *my_priv; /* local function prototypes */ @@ -92,8 +82,6 @@ static int tpmif_connect(struct xenbus_device *dev, struct tpm_private *tp, domid_t domid); static DECLARE_TASKLET(tpmif_rx_tasklet, tpmif_rx_action, 0); -static int tpmif_allocate_tx_buffers(struct tpm_private *tp); -static void tpmif_free_tx_buffers(struct tpm_private *tp); static void tpmif_set_connected_state(struct tpm_private *tp, u8 newstate); static int tpm_xmit(struct tpm_private *tp, @@ -101,52 +89,6 @@ static int tpm_xmit(struct tpm_private *tp, void *remember); static void destroy_tpmring(struct tpm_private *tp); -static inline int -tx_buffer_copy(struct tx_buffer *txb, const u8 *src, int len, - int isuserbuffer) -{ - int copied = len; - - if (len > txb->size) - copied = txb->size; - if (isuserbuffer) { - if (copy_from_user(txb->data, src, copied)) - return -EFAULT; - } else { - memcpy(txb->data, src, copied); - } - txb->len = len; - return copied; -} - -static inline struct tx_buffer *tx_buffer_alloc(void) -{ - struct tx_buffer *txb; - - txb = kzalloc(sizeof(struct tx_buffer), GFP_KERNEL); - if (!txb) - return NULL; - - txb->len = 0; - txb->size = PAGE_SIZE; - txb->data = (unsigned char *)__get_free_page(GFP_KERNEL); - if (txb->data == NULL) { - kfree(txb); - txb = NULL; - } - - return txb; -} - - -static inline void tx_buffer_free(struct tx_buffer *txb) -{ - if (txb) { - free_page((long)txb->data); - kfree(txb); - } -} - /************************************************************** Utility function for the tpm_private structure **************************************************************/ @@ -162,15 +104,12 @@ static void tpm_private_put(void) if (!atomic_dec_and_test(&my_priv->refcnt)) return; - tpmif_free_tx_buffers(my_priv); kfree(my_priv); my_priv = NULL; } static struct tpm_private *tpm_private_get(void) { - int err; - if (my_priv) { atomic_inc(&my_priv->refcnt); return my_priv; @@ -181,9 +120,6 @@ static struct tpm_private *tpm_private_get(void) return NULL; tpm_private_init(my_priv); - err = tpmif_allocate_tx_buffers(my_priv); - if (err < 0) - tpm_private_put(); return my_priv; } @@ -218,22 +154,22 @@ int vtpm_vd_send(struct tpm_private *tp, static int setup_tpmring(struct xenbus_device *dev, struct tpm_private *tp) { - struct tpmif_tx_interface *sring; + struct vtpm_shared_page *sring; int err; tp->ring_ref = GRANT_INVALID_REF; - sring = (void *)__get_free_page(GFP_KERNEL); + sring = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO); if (!sring) { xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); return -ENOMEM; } - tp->tx = sring; + tp->page = sring; - err = xenbus_grant_ring(dev, virt_to_mfn(tp->tx)); + err = xenbus_grant_ring(dev, virt_to_mfn(tp->page)); if (err < 0) { free_page((unsigned long)sring); - tp->tx = NULL; + tp->page = NULL; xenbus_dev_fatal(dev, err, "allocating grant reference"); goto fail; } @@ -256,9 +192,9 @@ static void destroy_tpmring(struct tpm_private *tp) if (tp->ring_ref != GRANT_INVALID_REF) { gnttab_end_foreign_access(tp->ring_ref, - 0, (unsigned long)tp->tx); + 0, (unsigned long)tp->page); tp->ring_ref = GRANT_INVALID_REF; - tp->tx = NULL; + tp->page = NULL; } if (tp->evtchn) @@ -470,62 +406,30 @@ static DEFINE_XENBUS_DRIVER(tpmfront, , .suspend = tpmfront_suspend, ); -static int tpmif_allocate_tx_buffers(struct tpm_private *tp) -{ - unsigned int i; - - for (i = 0; i < TPMIF_TX_RING_SIZE; i++) { - tp->tx_buffers[i] = tx_buffer_alloc(); - if (!tp->tx_buffers[i]) { - tpmif_free_tx_buffers(tp); - return -ENOMEM; - } - } - return 0; -} - -static void tpmif_free_tx_buffers(struct tpm_private *tp) -{ - unsigned int i; - - for (i = 0; i < TPMIF_TX_RING_SIZE; i++) - tx_buffer_free(tp->tx_buffers[i]); -} - static void tpmif_rx_action(unsigned long priv) { struct tpm_private *tp = (struct tpm_private *)priv; - int i = 0; unsigned int received; unsigned int offset = 0; u8 *buffer; - struct tpmif_tx_request *tx = &tp->tx->ring[i].req; + struct vtpm_shared_page *shr = tp->page; atomic_set(&tp->tx_busy, 0); wake_up_interruptible(&tp->wait_q); - received = tx->size; + offset = sizeof(*shr) + 4*shr->nr_extra_pages; + received = shr->length; + + if (offset > PAGE_SIZE || offset + received > PAGE_SIZE) { + printk(KERN_WARNING "tpmif_rx_action packet too large\n"); + return; + } buffer = kmalloc(received, GFP_ATOMIC); if (!buffer) return; - for (i = 0; i < TPMIF_TX_RING_SIZE && offset < received; i++) { - struct tx_buffer *txb = tp->tx_buffers[i]; - struct tpmif_tx_request *tx; - unsigned int tocopy; - - tx = &tp->tx->ring[i].req; - tocopy = tx->size; - if (tocopy > PAGE_SIZE) - tocopy = PAGE_SIZE; - - memcpy(&buffer[offset], txb->data, tocopy); - - gnttab_release_grant_reference(&gref_head, tx->ref); - - offset += tocopy; - } + memcpy(buffer, offset + (u8*)shr, received); vtpm_vd_recv(tp->chip, buffer, received, tp->tx_remember); kfree(buffer); @@ -550,8 +454,7 @@ static int tpm_xmit(struct tpm_private *tp, const u8 *buf, size_t count, int isuserbuffer, void *remember) { - struct tpmif_tx_request *tx; - int i; + struct vtpm_shared_page *shr; unsigned int offset = 0; spin_lock_irq(&tp->tx_lock); @@ -566,48 +469,23 @@ static int tpm_xmit(struct tpm_private *tp, return -EIO; } - for (i = 0; count > 0 && i < TPMIF_TX_RING_SIZE; i++) { - struct tx_buffer *txb = tp->tx_buffers[i]; - int copied; - - if (!txb) { - spin_unlock_irq(&tp->tx_lock); - return -EFAULT; - } - - copied = tx_buffer_copy(txb, &buf[offset], count, - isuserbuffer); - if (copied < 0) { - /* An error occurred */ - spin_unlock_irq(&tp->tx_lock); - return copied; - } - count -= copied; - offset += copied; - - tx = &tp->tx->ring[i].req; - tx->addr = virt_to_machine(txb->data).maddr; - tx->size = txb->len; - tx->unused = 0; - - /* Get the granttable reference for this page. */ - tx->ref = gnttab_claim_grant_reference(&gref_head); - if (tx->ref == -ENOSPC) { - spin_unlock_irq(&tp->tx_lock); - return -ENOSPC; - } - gnttab_grant_foreign_access_ref(tx->ref, - tp->backend_id, - virt_to_mfn(txb->data), - 0 /*RW*/); - wmb(); - } + shr = tp->page; + offset = sizeof(*shr) + 4*shr->nr_extra_pages; + + if (offset > PAGE_SIZE) + return -EIO; + + if (offset + count > PAGE_SIZE) + count = PAGE_SIZE - offset; + + memcpy(offset + (u8*)shr, buf, count); + shr->length = count; + barrier(); + shr->state = 1; atomic_set(&tp->tx_busy, 1); tp->tx_remember = remember; - mb(); - notify_remote_via_evtchn(tp->evtchn); spin_unlock_irq(&tp->tx_lock); @@ -667,12 +545,6 @@ static int __init tpmif_init(void) if (!tp) return -ENOMEM; - if (gnttab_alloc_grant_references(TPMIF_TX_RING_SIZE, - &gref_head) < 0) { - tpm_private_put(); - return -EFAULT; - } - return xenbus_register_frontend(&tpmfront_driver); } module_init(tpmif_init); @@ -680,7 +552,6 @@ module_init(tpmif_init); static void __exit tpmif_exit(void) { xenbus_unregister_driver(&tpmfront_driver); - gnttab_free_grant_references(gref_head); tpm_private_put(); } module_exit(tpmif_exit); diff --git a/include/xen/interface/io/tpmif.h b/include/xen/interface/io/tpmif.h index c9e7294..3d5c743 100644 --- a/include/xen/interface/io/tpmif.h +++ b/include/xen/interface/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 @@ -21,45 +21,21 @@ * 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 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. */ -}; -struct tpmif_tx_request; +struct vtpm_shared_page { + uint16_t length; /* request/response length in bytes */ -/* - * The TPMIF_TX_RING_SIZE defines the number of pages the - * front-end and backend can exchange (= size of array). - */ -#define TPMIF_TX_RING_SIZE 1 - -/* This structure must fit in a memory page. */ - -struct tpmif_ring { - struct tpmif_tx_request req; -}; -struct tpmif_ring; + 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 */ }; -struct tpmif_tx_interface; #endif -- 1.7.11.7 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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