[PATCH v2] add xen-tpmfront.ko: Xen Virtual TPM frontend driver

* [PATCH v2] add xen-tpmfront.ko: Xen Virtual TPM frontend driver
@ 2012-11-12 14:29 Matthew Fioravante
  2012-11-12 16:30 ` Konrad Rzeszutek Wilk
  0 siblings, 1 reply; 4+ messages in thread
From: Matthew Fioravante @ 2012-11-12 14:29 UTC (permalink / raw)
  To: key, mail, tpmdd, tpmdd, konrad.wilk, jeremy, tpmdd-devel,
	linux-kernel, xen-devel
  Cc: Matthew Fioravante

This patch ports the xen vtpm frontend driver for linux
from the linux-2.6.18-xen.hg tree to linux-stable. This
driver is designed be used with the mini-os tpmback driver
in Xen as part of the new mini-os virtual tpm subsystem.
See docs/misc/vtpm.txt in Xen and the xen-devel mailing list
for details.

Signed-off-by: Matthew Fioravante <matthew.fioravante@jhuapl.edu>
---
 drivers/char/tpm/Kconfig             |   11 +
 drivers/char/tpm/Makefile            |    2 +
 drivers/char/tpm/tpm.h               |   10 +
 drivers/char/tpm/xen-tpmfront_if.c   |  688 ++++++++++++++++++++++++++++++++++
 drivers/char/tpm/xen-tpmfront_vtpm.c |  543 +++++++++++++++++++++++++++
 drivers/char/tpm/xen-tpmfront_vtpm.h |   55 +++
 include/xen/interface/io/tpmif.h     |   65 ++++
 7 files changed, 1374 insertions(+)
 create mode 100644 drivers/char/tpm/xen-tpmfront_if.c
 create mode 100644 drivers/char/tpm/xen-tpmfront_vtpm.c
 create mode 100644 drivers/char/tpm/xen-tpmfront_vtpm.h
 create mode 100644 include/xen/interface/io/tpmif.h

diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 915875e..23d272f 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -81,4 +81,15 @@ config TCG_IBMVTPM
 	  will be accessible from within Linux.  To compile this driver
 	  as a module, choose M here; the module will be called tpm_ibmvtpm.
 
+config TCG_XEN
+	tristate "XEN TPM Interface"
+	depends on TCG_TPM && XEN
+	---help---
+	  If you want to make TPM support available to a Xen user domain,
+	  say Yes and it will be accessible from within Linux. See
+	  the manpages for xl, xl.conf, and docs/misc/vtpm.txt in
+	  the Xen source repository for more details.
+	  To compile this driver as a module, choose M here; the module
+	  will be called xen-tpmfront.
+
 endif # TCG_TPM
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 5b3fc8b..0161f05 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -17,3 +17,5 @@ obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
 obj-$(CONFIG_TCG_ATMEL) += tpm_atmel.o
 obj-$(CONFIG_TCG_INFINEON) += tpm_infineon.o
 obj-$(CONFIG_TCG_IBMVTPM) += tpm_ibmvtpm.o
+obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
+xen-tpmfront-y = xen-tpmfront_if.o xen-tpmfront_vtpm.o
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 8ef7649..b575892 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -328,6 +328,16 @@ extern int tpm_pm_resume(struct device *);
 extern int wait_for_tpm_stat(struct tpm_chip *, u8, unsigned long,
 			     wait_queue_head_t *);
 
+static inline void *chip_get_private(const struct tpm_chip *chip)
+{
+	return chip->vendor.data;
+}
+
+static inline void chip_set_private(struct tpm_chip *chip, void *priv)
+{
+	chip->vendor.data = priv;
+}
+
 #ifdef CONFIG_ACPI
 extern int tpm_add_ppi(struct kobject *);
 extern void tpm_remove_ppi(struct kobject *);
diff --git a/drivers/char/tpm/xen-tpmfront_if.c b/drivers/char/tpm/xen-tpmfront_if.c
new file mode 100644
index 0000000..ba7fad8
--- /dev/null
+++ b/drivers/char/tpm/xen-tpmfront_if.c
@@ -0,0 +1,688 @@
+/*
+ * Copyright (c) 2005, IBM Corporation
+ *
+ * Author: Stefan Berger, stefanb@us.ibm.com
+ * Grant table support: Mahadevan Gomathisankaran
+ *
+ * This code has been derived from drivers/xen/netfront/netfront.c
+ *
+ * Copyright (c) 2002-2004, K A Fraser
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+#include <xen/events.h>
+#include <xen/interface/grant_table.h>
+#include <xen/interface/io/tpmif.h>
+#include <xen/grant_table.h>
+#include <xen/xenbus.h>
+#include <xen/page.h>
+#include "tpm.h"
+#include "xen-tpmfront_vtpm.h"
+
+#define GRANT_INVALID_REF 0
+
+/* local structures */
+struct tpm_private {
+	struct tpm_chip *chip;
+
+	struct tpmif_tx_interface *tx;
+	atomic_t refcnt;
+	unsigned int evtchn;
+	u8 is_connected;
+	u8 is_suspended;
+
+	spinlock_t tx_lock;
+
+	struct tx_buffer *tx_buffers[TPMIF_TX_RING_SIZE];
+
+	atomic_t tx_busy;
+	void *tx_remember;
+
+	domid_t backend_id;
+	wait_queue_head_t wait_q;
+
+	struct xenbus_device *dev;
+	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 */
+static irqreturn_t tpmif_int(int irq,
+		void *tpm_priv);
+static void tpmif_rx_action(unsigned long unused);
+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,
+		const u8 *buf, size_t count, int userbuffer,
+		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
+ **************************************************************/
+static void tpm_private_init(struct tpm_private *tp)
+{
+	spin_lock_init(&tp->tx_lock);
+	init_waitqueue_head(&tp->wait_q);
+	atomic_set(&tp->refcnt, 1);
+}
+
+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;
+	}
+
+	my_priv = kzalloc(sizeof(struct tpm_private), GFP_KERNEL);
+	if (!my_priv)
+		return NULL;
+
+	tpm_private_init(my_priv);
+	err = tpmif_allocate_tx_buffers(my_priv);
+	if (err < 0)
+		tpm_private_put();
+
+	return my_priv;
+}
+
+/**************************************************************
+
+  The interface to let the tpm plugin register its callback
+  function and send data to another partition using this module
+
+ **************************************************************/
+
+static DEFINE_MUTEX(suspend_lock);
+/*
+ * Send data via this module by calling this function
+ */
+int vtpm_vd_send(struct tpm_private *tp,
+		const u8 *buf, size_t count, void *ptr)
+{
+	int sent;
+
+	mutex_lock(&suspend_lock);
+	sent = tpm_xmit(tp, buf, count, 0, ptr);
+	mutex_unlock(&suspend_lock);
+
+	return sent;
+}
+
+/**************************************************************
+  XENBUS support code
+ **************************************************************/
+
+static int setup_tpmring(struct xenbus_device *dev,
+		struct tpm_private *tp)
+{
+	struct tpmif_tx_interface *sring;
+	int err;
+
+	tp->ring_ref = GRANT_INVALID_REF;
+
+	sring = (void *)__get_free_page(GFP_KERNEL);
+	if (!sring) {
+		xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
+		return -ENOMEM;
+	}
+	tp->tx = sring;
+
+	err = xenbus_grant_ring(dev, virt_to_mfn(tp->tx));
+	if (err < 0) {
+		free_page((unsigned long)sring);
+		tp->tx = NULL;
+		xenbus_dev_fatal(dev, err, "allocating grant reference");
+		goto fail;
+	}
+	tp->ring_ref = err;
+
+	err = tpmif_connect(dev, tp, dev->otherend_id);
+	if (err)
+		goto fail;
+
+	return 0;
+fail:
+	destroy_tpmring(tp);
+	return err;
+}
+
+
+static void destroy_tpmring(struct tpm_private *tp)
+{
+	tpmif_set_connected_state(tp, 0);
+
+	if (tp->ring_ref != GRANT_INVALID_REF) {
+		gnttab_end_foreign_access(tp->ring_ref,
+				0, (unsigned long)tp->tx);
+		tp->ring_ref = GRANT_INVALID_REF;
+		tp->tx = NULL;
+	}
+
+	if (tp->evtchn)
+		unbind_from_irqhandler(irq_from_evtchn(tp->evtchn), tp);
+
+	tp->evtchn = GRANT_INVALID_REF;
+}
+
+
+static int talk_to_backend(struct xenbus_device *dev,
+		struct tpm_private *tp)
+{
+	const char *message = NULL;
+	int err;
+	struct xenbus_transaction xbt;
+
+	err = setup_tpmring(dev, tp);
+	if (err) {
+		xenbus_dev_fatal(dev, err, "setting up ring");
+		goto out;
+	}
+
+again:
+	err = xenbus_transaction_start(&xbt);
+	if (err) {
+		xenbus_dev_fatal(dev, err, "starting transaction");
+		goto destroy_tpmring;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename,
+			"ring-ref", "%u", tp->ring_ref);
+	if (err) {
+		message = "writing ring-ref";
+		goto abort_transaction;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
+			tp->evtchn);
+	if (err) {
+		message = "writing event-channel";
+		goto abort_transaction;
+	}
+
+	err = xenbus_transaction_end(xbt, 0);
+	if (err == -EAGAIN)
+		goto again;
+	if (err) {
+		xenbus_dev_fatal(dev, err, "completing transaction");
+		goto destroy_tpmring;
+	}
+
+	xenbus_switch_state(dev, XenbusStateConnected);
+
+	return 0;
+
+abort_transaction:
+	xenbus_transaction_end(xbt, 1);
+	if (message)
+		xenbus_dev_error(dev, err, "%s", message);
+destroy_tpmring:
+	destroy_tpmring(tp);
+out:
+	return err;
+}
+
+/**
+ * Callback received when the backend's state changes.
+ */
+static void backend_changed(struct xenbus_device *dev,
+		enum xenbus_state backend_state)
+{
+	struct tpm_private *tp = tpm_private_from_dev(&dev->dev);
+
+	switch (backend_state) {
+	case XenbusStateInitialising:
+	case XenbusStateInitWait:
+	case XenbusStateInitialised:
+	case XenbusStateReconfiguring:
+	case XenbusStateReconfigured:
+	case XenbusStateUnknown:
+		break;
+
+	case XenbusStateConnected:
+		tpmif_set_connected_state(tp, 1);
+		break;
+
+	case XenbusStateClosing:
+		tpmif_set_connected_state(tp, 0);
+		xenbus_frontend_closed(dev);
+		break;
+
+	case XenbusStateClosed:
+		tpmif_set_connected_state(tp, 0);
+		if (tp->is_suspended == 0)
+			device_unregister(&dev->dev);
+		xenbus_frontend_closed(dev);
+		break;
+	}
+}
+
+static int tpmfront_probe(struct xenbus_device *dev,
+		const struct xenbus_device_id *id)
+{
+	int err;
+	int handle;
+	struct tpm_private *tp = tpm_private_get();
+
+	if (!tp)
+		return -ENOMEM;
+
+	tp->chip = init_vtpm(&dev->dev, tp);
+	if (IS_ERR(tp->chip))
+		return PTR_ERR(tp->chip);
+
+	err = xenbus_scanf(XBT_NIL, dev->nodename,
+			"handle", "%i", &handle);
+	if (XENBUS_EXIST_ERR(err))
+		return err;
+
+	if (err < 0) {
+		xenbus_dev_fatal(dev, err, "reading virtual-device");
+		return err;
+	}
+
+	tp->dev = dev;
+
+	err = talk_to_backend(dev, tp);
+	if (err) {
+		tpm_private_put();
+		return err;
+	}
+
+	return 0;
+}
+
+
+static int __devexit tpmfront_remove(struct xenbus_device *dev)
+{
+	struct tpm_private *tp = tpm_private_from_dev(&dev->dev);
+	destroy_tpmring(tp);
+	cleanup_vtpm(&dev->dev);
+	return 0;
+}
+
+static int tpmfront_suspend(struct xenbus_device *dev)
+{
+	struct tpm_private *tp = tpm_private_from_dev(&dev->dev);
+	u32 ctr;
+
+	/* Take the lock, preventing any application from sending. */
+	mutex_lock(&suspend_lock);
+	tp->is_suspended = 1;
+
+	for (ctr = 0; atomic_read(&tp->tx_busy); ctr++) {
+		/* Wait for a request to be responded to. */
+		interruptible_sleep_on_timeout(&tp->wait_q, 100);
+	}
+
+	return 0;
+}
+
+static int tpmfront_suspend_finish(struct tpm_private *tp)
+{
+	tp->is_suspended = 0;
+	/* Allow applications to send again. */
+	mutex_unlock(&suspend_lock);
+	return 0;
+}
+
+static int tpmfront_resume(struct xenbus_device *dev)
+{
+	struct tpm_private *tp = tpm_private_from_dev(&dev->dev);
+	destroy_tpmring(tp);
+	return talk_to_backend(dev, tp);
+}
+
+static int tpmif_connect(struct xenbus_device *dev,
+		struct tpm_private *tp,
+		domid_t domid)
+{
+	int err;
+
+	tp->backend_id = domid;
+	tp->evtchn = GRANT_INVALID_REF;
+
+	err = xenbus_alloc_evtchn(dev, &tp->evtchn);
+	if (err)
+		return err;
+
+	err = bind_evtchn_to_irqhandler(tp->evtchn, tpmif_int,
+			0, "tpmif", tp);
+	if (err <= 0)
+		return err;
+
+	return 0;
+}
+
+static const struct xenbus_device_id tpmfront_ids[] = {
+	{ "vtpm" },
+	{ "" }
+};
+MODULE_ALIAS("xen:vtpm");
+
+static DEFINE_XENBUS_DRIVER(tpmfront, ,
+		.probe = tpmfront_probe,
+		.remove =  __devexit_p(tpmfront_remove),
+		.resume = tpmfront_resume,
+		.otherend_changed = backend_changed,
+		.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;
+
+	atomic_set(&tp->tx_busy, 0);
+	wake_up_interruptible(&tp->wait_q);
+
+	received = tx->size;
+
+	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;
+	}
+
+	vtpm_vd_recv(tp->chip, buffer, received, tp->tx_remember);
+	kfree(buffer);
+}
+
+
+static irqreturn_t tpmif_int(int irq, void *tpm_priv)
+{
+	struct tpm_private *tp = tpm_priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tp->tx_lock, flags);
+	tpmif_rx_tasklet.data = (unsigned long)tp;
+	tasklet_schedule(&tpmif_rx_tasklet);
+	spin_unlock_irqrestore(&tp->tx_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+
+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;
+	unsigned int offset = 0;
+
+	spin_lock_irq(&tp->tx_lock);
+
+	if (unlikely(atomic_read(&tp->tx_busy))) {
+		spin_unlock_irq(&tp->tx_lock);
+		return -EBUSY;
+	}
+
+	if (tp->is_connected != 1) {
+		spin_unlock_irq(&tp->tx_lock);
+		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();
+	}
+
+	atomic_set(&tp->tx_busy, 1);
+	tp->tx_remember = remember;
+
+	mb();
+
+	notify_remote_via_evtchn(tp->evtchn);
+
+	spin_unlock_irq(&tp->tx_lock);
+	return offset;
+}
+
+
+static void tpmif_notify_upperlayer(struct tpm_private *tp)
+{
+	/* Notify upper layer about the state of the connection to the BE. */
+	vtpm_vd_status(tp->chip, (tp->is_connected
+				? TPM_VD_STATUS_CONNECTED
+				: TPM_VD_STATUS_DISCONNECTED));
+}
+
+
+static void tpmif_set_connected_state(struct tpm_private *tp, u8 is_connected)
+{
+	/*
+	 * Don't notify upper layer if we are in suspend mode and
+	 * should disconnect - assumption is that we will resume
+	 * The mutex keeps apps from sending.
+	 */
+	if (is_connected == 0 && tp->is_suspended == 1)
+		return;
+
+	/*
+	 * Unlock the mutex if we are connected again
+	 * after being suspended - now resuming.
+	 * This also removes the suspend state.
+	 */
+	if (is_connected == 1 && tp->is_suspended == 1)
+		tpmfront_suspend_finish(tp);
+
+	if (is_connected != tp->is_connected) {
+		tp->is_connected = is_connected;
+		tpmif_notify_upperlayer(tp);
+	}
+}
+
+
+
+/* =================================================================
+ * Initialization function.
+ * =================================================================
+ */
+
+
+static int __init tpmif_init(void)
+{
+	struct tpm_private *tp;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	tp = tpm_private_get();
+	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);
+
+static void __exit tpmif_exit(void)
+{
+	xenbus_unregister_driver(&tpmfront_driver);
+	gnttab_free_grant_references(gref_head);
+	tpm_private_put();
+}
+module_exit(tpmif_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/drivers/char/tpm/xen-tpmfront_vtpm.c b/drivers/char/tpm/xen-tpmfront_vtpm.c
new file mode 100644
index 0000000..d70f1df
--- /dev/null
+++ b/drivers/char/tpm/xen-tpmfront_vtpm.c
@@ -0,0 +1,543 @@
+/*
+ * Copyright (C) 2006 IBM Corporation
+ *
+ * Authors:
+ * Stefan Berger <stefanb@us.ibm.com>
+ *
+ * Generic device driver part for device drivers in a virtualized
+ * environment.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ */
+
+#include <linux/uaccess.h>
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include "tpm.h"
+#include "xen-tpmfront_vtpm.h"
+
+/* read status bits */
+enum {
+	STATUS_BUSY = 0x01,
+	STATUS_DATA_AVAIL = 0x02,
+	STATUS_READY = 0x04
+};
+
+struct transmission {
+	struct list_head next;
+
+	unsigned char *request;
+	size_t  request_len;
+	size_t  request_buflen;
+
+	unsigned char *response;
+	size_t  response_len;
+	size_t  response_buflen;
+
+	unsigned int flags;
+};
+
+enum {
+	TRANSMISSION_FLAG_WAS_QUEUED = 0x1
+};
+
+
+enum {
+	DATAEX_FLAG_QUEUED_ONLY = 0x1
+};
+
+
+/* local variables */
+
+/* local function prototypes */
+static int _vtpm_send_queued(struct tpm_chip *chip);
+
+
+/* =============================================================
+ * Some utility functions
+ * =============================================================
+ */
+static void vtpm_state_init(struct vtpm_state *vtpms)
+{
+	vtpms->current_request = NULL;
+	spin_lock_init(&vtpms->req_list_lock);
+	init_waitqueue_head(&vtpms->req_wait_queue);
+	INIT_LIST_HEAD(&vtpms->queued_requests);
+
+	vtpms->current_response = NULL;
+	spin_lock_init(&vtpms->resp_list_lock);
+	init_waitqueue_head(&vtpms->resp_wait_queue);
+
+	vtpms->disconnect_time = jiffies;
+}
+
+
+static inline struct transmission *transmission_alloc(void)
+{
+	return kzalloc(sizeof(struct transmission), GFP_ATOMIC);
+}
+
+static unsigned char *
+transmission_set_req_buffer(struct transmission *t,
+		unsigned char *buffer, size_t len)
+{
+	if (t->request_buflen < len) {
+		kfree(t->request);
+		t->request = kmalloc(len, GFP_KERNEL);
+		if (!t->request) {
+			t->request_buflen = 0;
+			return NULL;
+		}
+		t->request_buflen = len;
+	}
+
+	memcpy(t->request, buffer, len);
+	t->request_len = len;
+
+	return t->request;
+}
+
+static unsigned char *
+transmission_set_res_buffer(struct transmission *t,
+		const unsigned char *buffer, size_t len)
+{
+	if (t->response_buflen < len) {
+		kfree(t->response);
+		t->response = kmalloc(len, GFP_ATOMIC);
+		if (!t->response) {
+			t->response_buflen = 0;
+			return NULL;
+		}
+		t->response_buflen = len;
+	}
+
+	memcpy(t->response, buffer, len);
+	t->response_len = len;
+
+	return t->response;
+}
+
+static inline void transmission_free(struct transmission *t)
+{
+	kfree(t->request);
+	kfree(t->response);
+	kfree(t);
+}
+
+/* =============================================================
+ * Interface with the lower layer driver
+ * =============================================================
+ */
+/*
+ * Lower layer uses this function to make a response available.
+ */
+int vtpm_vd_recv(const struct tpm_chip *chip,
+		const unsigned char *buffer, size_t count,
+		void *ptr)
+{
+	unsigned long flags;
+	int ret_size = 0;
+	struct transmission *t;
+	struct vtpm_state *vtpms;
+
+	vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	/*
+	 * The list with requests must contain one request
+	 * only and the element there must be the one that
+	 * was passed to me from the front-end.
+	 */
+	spin_lock_irqsave(&vtpms->resp_list_lock, flags);
+	if (vtpms->current_request != ptr) {
+		spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+		return 0;
+	}
+	t = vtpms->current_request;
+	if (t) {
+		transmission_free(t);
+		vtpms->current_request = NULL;
+	}
+
+	t = transmission_alloc();
+	if (t) {
+		if (!transmission_set_res_buffer(t, buffer, count)) {
+			transmission_free(t);
+			spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+			return -ENOMEM;
+		}
+		ret_size = count;
+		vtpms->current_response = t;
+		wake_up_interruptible(&vtpms->resp_wait_queue);
+	}
+	spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+
+	return ret_size;
+}
+
+
+/*
+ * Lower layer indicates its status (connected/disconnected)
+ */
+void vtpm_vd_status(const struct tpm_chip *chip, u8 vd_status)
+{
+	struct vtpm_state *vtpms;
+
+	vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	vtpms->vd_status = vd_status;
+	if ((vtpms->vd_status & TPM_VD_STATUS_CONNECTED) == 0)
+		vtpms->disconnect_time = jiffies;
+}
+
+/* =============================================================
+ * Interface with the generic TPM driver
+ * =============================================================
+ */
+static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	int rc = 0;
+	unsigned long flags;
+	struct vtpm_state *vtpms;
+
+	vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	/*
+	 * Check if the previous operation only queued the command
+	 * In this case there won't be a response, so I just
+	 * return from here and reset that flag. In any other
+	 * case I should receive a response from the back-end.
+	 */
+	spin_lock_irqsave(&vtpms->resp_list_lock, flags);
+	if ((vtpms->flags & DATAEX_FLAG_QUEUED_ONLY) != 0) {
+		vtpms->flags &= ~DATAEX_FLAG_QUEUED_ONLY;
+		spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+		/*
+		 * The first few commands (measurements) must be
+		 * queued since it might not be possible to talk to the
+		 * TPM, yet.
+		 * Return a response of up to 30 '0's.
+		 */
+
+		count = min_t(size_t, count, 30);
+		memset(buf, 0x0, count);
+		return count;
+	}
+	/*
+	 * Check whether something is in the responselist and if
+	 * there's nothing in the list wait for something to appear.
+	 */
+
+	if (!vtpms->current_response) {
+		spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+		interruptible_sleep_on_timeout(&vtpms->resp_wait_queue,
+				1000);
+		spin_lock_irqsave(&vtpms->resp_list_lock, flags);
+	}
+
+	if (vtpms->current_response) {
+		struct transmission *t = vtpms->current_response;
+		vtpms->current_response = NULL;
+		rc = min(count, t->response_len);
+		memcpy(buf, t->response, rc);
+		transmission_free(t);
+	}
+
+	spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+	return rc;
+}
+
+static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	int rc = 0;
+	unsigned long flags;
+	struct transmission *t = transmission_alloc();
+	struct vtpm_state *vtpms;
+
+	vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	if (!t)
+		return -ENOMEM;
+	/*
+	 * If there's a current request, it must be the
+	 * previous request that has timed out.
+	 */
+	spin_lock_irqsave(&vtpms->req_list_lock, flags);
+	if (vtpms->current_request != NULL) {
+		dev_warn(chip->dev, "Sending although there is a request outstanding.\n"
+				"         Previous request must have timed out.\n");
+		transmission_free(vtpms->current_request);
+		vtpms->current_request = NULL;
+	}
+	spin_unlock_irqrestore(&vtpms->req_list_lock, flags);
+
+	/*
+	 * Queue the packet if the driver below is not
+	 * ready, yet, or there is any packet already
+	 * in the queue.
+	 * If the driver below is ready, unqueue all
+	 * packets first before sending our current
+	 * packet.
+	 * For each unqueued packet, except for the
+	 * last (=current) packet, call the function
+	 * tpm_xen_recv to wait for the response to come
+	 * back.
+	 */
+	if ((vtpms->vd_status & TPM_VD_STATUS_CONNECTED) == 0) {
+		if (time_after(jiffies,
+					vtpms->disconnect_time + HZ * 10)) {
+			rc = -ENOENT;
+		} else {
+			goto queue_it;
+		}
+	} else {
+		/*
+		 * Send all queued packets.
+		 */
+		if (_vtpm_send_queued(chip) == 0) {
+
+			vtpms->current_request = t;
+
+			rc = vtpm_vd_send(vtpms->tpm_private,
+					buf,
+					count,
+					t);
+			/*
+			 * The generic TPM driver will call
+			 * the function to receive the response.
+			 */
+			if (rc < 0) {
+				vtpms->current_request = NULL;
+				goto queue_it;
+			}
+		} else {
+queue_it:
+			if (!transmission_set_req_buffer(t, buf, count)) {
+				transmission_free(t);
+				rc = -ENOMEM;
+				goto exit;
+			}
+			/*
+			 * An error occurred. Don't event try
+			 * to send the current request. Just
+			 * queue it.
+			 */
+			spin_lock_irqsave(&vtpms->req_list_lock, flags);
+			vtpms->flags |= DATAEX_FLAG_QUEUED_ONLY;
+			list_add_tail(&t->next, &vtpms->queued_requests);
+			spin_unlock_irqrestore(&vtpms->req_list_lock, flags);
+		}
+	}
+
+exit:
+	return rc;
+}
+
+
+/*
+ * Send all queued requests.
+ */
+static int _vtpm_send_queued(struct tpm_chip *chip)
+{
+	int rc;
+	int error = 0;
+	unsigned long flags;
+	unsigned char buffer[1];
+	struct vtpm_state *vtpms;
+	vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	spin_lock_irqsave(&vtpms->req_list_lock, flags);
+
+	while (!list_empty(&vtpms->queued_requests)) {
+		/*
+		 * Need to dequeue them.
+		 * Read the result into a dummy buffer.
+		 */
+		struct transmission *qt = (struct transmission *)
+			vtpms->queued_requests.next;
+		list_del(&qt->next);
+		vtpms->current_request = qt;
+		spin_unlock_irqrestore(&vtpms->req_list_lock, flags);
+
+		rc = vtpm_vd_send(vtpms->tpm_private,
+				qt->request,
+				qt->request_len,
+				qt);
+
+		if (rc < 0) {
+			spin_lock_irqsave(&vtpms->req_list_lock, flags);
+			qt = vtpms->current_request;
+			if (qt != NULL) {
+				/*
+				 * requeue it at the beginning
+				 * of the list
+				 */
+				list_add(&qt->next,
+						&vtpms->queued_requests);
+			}
+			vtpms->current_request = NULL;
+			error = 1;
+			break;
+		}
+		/*
+		 * After this point qt is not valid anymore!
+		 * It is freed when the front-end is delivering
+		 * the data by calling tpm_recv
+		 */
+		/*
+		 * Receive response into provided dummy buffer
+		 */
+		rc = vtpm_recv(chip, buffer, sizeof(buffer));
+		spin_lock_irqsave(&vtpms->req_list_lock, flags);
+	}
+
+	spin_unlock_irqrestore(&vtpms->req_list_lock, flags);
+
+	return error;
+}
+
+static void vtpm_cancel(struct tpm_chip *chip)
+{
+	unsigned long flags;
+	struct vtpm_state *vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	spin_lock_irqsave(&vtpms->resp_list_lock, flags);
+
+	if (!vtpms->current_response && vtpms->current_request) {
+		spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+		interruptible_sleep_on(&vtpms->resp_wait_queue);
+		spin_lock_irqsave(&vtpms->resp_list_lock, flags);
+	}
+
+	if (vtpms->current_response) {
+		struct transmission *t = vtpms->current_response;
+		vtpms->current_response = NULL;
+		transmission_free(t);
+	}
+
+	spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+}
+
+static u8 vtpm_status(struct tpm_chip *chip)
+{
+	u8 rc = 0;
+	unsigned long flags;
+	struct vtpm_state *vtpms;
+
+	vtpms = (struct vtpm_state *)chip_get_private(chip);
+
+	spin_lock_irqsave(&vtpms->resp_list_lock, flags);
+	/*
+	 * Data are available if:
+	 *  - there's a current response
+	 *  - the last packet was queued only (this is fake, but necessary to
+	 *      get the generic TPM layer to call the receive function.)
+	 */
+	if (vtpms->current_response ||
+			0 != (vtpms->flags & DATAEX_FLAG_QUEUED_ONLY)) {
+		rc = STATUS_DATA_AVAIL;
+	} else if (!vtpms->current_response && !vtpms->current_request) {
+		rc = STATUS_READY;
+	}
+
+	spin_unlock_irqrestore(&vtpms->resp_list_lock, flags);
+	return rc;
+}
+
+static const struct file_operations vtpm_ops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.open = tpm_open,
+	.read = tpm_read,
+	.write = tpm_write,
+	.release = tpm_release,
+};
+
+static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
+static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
+static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
+static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
+static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
+static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
+		NULL);
+static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
+static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
+
+static struct attribute *vtpm_attrs[] = {
+	&dev_attr_pubek.attr,
+	&dev_attr_pcrs.attr,
+	&dev_attr_enabled.attr,
+	&dev_attr_active.attr,
+	&dev_attr_owned.attr,
+	&dev_attr_temp_deactivated.attr,
+	&dev_attr_caps.attr,
+	&dev_attr_cancel.attr,
+	NULL,
+};
+
+static struct attribute_group vtpm_attr_grp = { .attrs = vtpm_attrs };
+
+#define TPM_LONG_TIMEOUT   (10 * 60 * HZ)
+
+static struct tpm_vendor_specific tpm_vtpm = {
+	.recv = vtpm_recv,
+	.send = vtpm_send,
+	.cancel = vtpm_cancel,
+	.status = vtpm_status,
+	.req_complete_mask = STATUS_BUSY | STATUS_DATA_AVAIL,
+	.req_complete_val  = STATUS_DATA_AVAIL,
+	.req_canceled = STATUS_READY,
+	.attr_group = &vtpm_attr_grp,
+	.miscdev = {
+		.fops = &vtpm_ops,
+	},
+	.duration = {
+		TPM_LONG_TIMEOUT,
+		TPM_LONG_TIMEOUT,
+		TPM_LONG_TIMEOUT,
+	},
+};
+
+struct tpm_chip *init_vtpm(struct device *dev,
+		struct tpm_private *tp)
+{
+	long rc;
+	struct tpm_chip *chip;
+	struct vtpm_state *vtpms;
+
+	vtpms = kzalloc(sizeof(struct vtpm_state), GFP_KERNEL);
+	if (!vtpms)
+		return ERR_PTR(-ENOMEM);
+
+	vtpm_state_init(vtpms);
+	vtpms->tpm_private = tp;
+
+	chip = tpm_register_hardware(dev, &tpm_vtpm);
+	if (!chip) {
+		rc = -ENODEV;
+		goto err_free_mem;
+	}
+
+	chip_set_private(chip, vtpms);
+
+	return chip;
+
+err_free_mem:
+	kfree(vtpms);
+
+	return ERR_PTR(rc);
+}
+
+void cleanup_vtpm(struct device *dev)
+{
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+	struct vtpm_state *vtpms = (struct vtpm_state *)chip_get_private(chip);
+	tpm_remove_hardware(dev);
+	kfree(vtpms);
+}
diff --git a/drivers/char/tpm/xen-tpmfront_vtpm.h b/drivers/char/tpm/xen-tpmfront_vtpm.h
new file mode 100644
index 0000000..16cf323
--- /dev/null
+++ b/drivers/char/tpm/xen-tpmfront_vtpm.h
@@ -0,0 +1,55 @@
+#ifndef XEN_TPMFRONT_VTPM_H
+#define XEN_TPMFRONT_VTPM_H
+
+struct tpm_chip;
+struct tpm_private;
+
+struct vtpm_state {
+	struct transmission *current_request;
+	spinlock_t           req_list_lock;
+	wait_queue_head_t    req_wait_queue;
+
+	struct list_head     queued_requests;
+
+	struct transmission *current_response;
+	spinlock_t           resp_list_lock;
+	wait_queue_head_t    resp_wait_queue;
+
+	u8                   vd_status;
+	u8                   flags;
+
+	unsigned long        disconnect_time;
+
+	/*
+	 * The following is a private structure of the underlying
+	 * driver. It is passed as parameter in the send function.
+	 */
+	struct tpm_private *tpm_private;
+};
+
+
+enum vdev_status {
+	TPM_VD_STATUS_DISCONNECTED = 0x0,
+	TPM_VD_STATUS_CONNECTED = 0x1
+};
+
+/* this function is called from tpm_vtpm.c */
+int vtpm_vd_send(struct tpm_private *tp,
+		const u8 *buf, size_t count, void *ptr);
+
+/* these functions are offered by tpm_vtpm.c */
+struct tpm_chip *init_vtpm(struct device *,
+		struct tpm_private *);
+void cleanup_vtpm(struct device *);
+int vtpm_vd_recv(const struct tpm_chip *chip,
+		const unsigned char *buffer, size_t count, void *ptr);
+void vtpm_vd_status(const struct tpm_chip *, u8 status);
+
+static inline struct tpm_private *tpm_private_from_dev(struct device *dev)
+{
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+	struct vtpm_state *vtpms = (struct vtpm_state *)chip->vendor.data;
+	return vtpms->tpm_private;
+}
+
+#endif
diff --git a/include/xen/interface/io/tpmif.h b/include/xen/interface/io/tpmif.h
new file mode 100644
index 0000000..c9e7294
--- /dev/null
+++ b/include/xen/interface/io/tpmif.h
@@ -0,0 +1,65 @@
+/******************************************************************************
+ * tpmif.h
+ *
+ * TPM I/O interface for Xen guest OSes.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * 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@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.        */
+};
+struct tpmif_tx_request;
+
+/*
+ * 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;
+
+struct tpmif_tx_interface {
+	struct tpmif_ring ring[TPMIF_TX_RING_SIZE];
+};
+struct tpmif_tx_interface;
+
+#endif
-- 
1.7.10.4


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