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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH RFC] drivers/tpm: add xen tpmfront interface
This is a complete rewrite of the Xen TPM frontend driver, taking
advantage of a simplified frontend/backend interface and adding support
for cancellation and timeouts.
Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
This patch does not include the v1 interfaces from linux-2.6.18-xen.hg
in include/xen/interface/io/tpmif.h, since they do not pass checkpatch
due to their use of typedefs, are not 32/64-bit clean, and are not used
in this patch.
This patch relies on the mini-os patch to tpmback/front:
[PATCH v5.1 01/12] mini-os/tpm{back,front}: Change shared page ABI
which should be sent as a reply.
drivers/char/tpm/Kconfig | 11 ++
drivers/char/tpm/Makefile | 1 +
drivers/char/tpm/tpm.h | 10 +
drivers/char/tpm/xen-tpmfront.c | 418 +++++++++++++++++++++++++++++++++++++++
include/xen/interface/io/tpmif.h | 50 +++++
5 files changed, 490 insertions(+)
create mode 100644 drivers/char/tpm/xen-tpmfront.c
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..424ecaa 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -17,3 +17,4 @@ 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
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.c b/drivers/char/tpm/xen-tpmfront.c
new file mode 100644
index 0000000..c02f172
--- /dev/null
+++ b/drivers/char/tpm/xen-tpmfront.c
@@ -0,0 +1,418 @@
+#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"
+
+struct tpm_private {
+ struct tpm_chip *chip;
+ struct xenbus_device *dev;
+
+ struct vtpm_shared_page *shr;
+
+ unsigned int evtchn;
+ int ring_ref;
+ domid_t backend_id;
+};
+
+enum status_bits {
+ VTPM_STATUS_RUNNING = 0x1,
+ VTPM_STATUS_IDLE = 0x2,
+ VTPM_STATUS_RESULT = 0x4,
+ VTPM_STATUS_CANCELED = 0x8,
+};
+
+static u8 vtpm_status(struct tpm_chip *chip)
+{
+ struct tpm_private *priv = chip_get_private(chip);
+ switch (priv->shr->state) {
+ case VTPM_STATE_IDLE:
+ return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED;
+ case VTPM_STATE_FINISH:
+ return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT;
+ case VTPM_STATE_SUBMIT:
+ case VTPM_STATE_CANCEL:
+ return VTPM_STATUS_RUNNING;
+ default:
+ return 0;
+ }
+}
+
+static void vtpm_cancel(struct tpm_chip *chip)
+{
+ struct tpm_private *priv = chip_get_private(chip);
+ priv->shr->state = VTPM_STATE_CANCEL;
+ notify_remote_via_evtchn(priv->evtchn);
+}
+
+static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+ struct tpm_private *priv = chip_get_private(chip);
+ struct vtpm_shared_page *shr = priv->shr;
+ unsigned int offset = sizeof(*shr) + 4*shr->nr_extra_pages;
+
+ u32 ordinal;
+ unsigned long duration;
+
+ if (count < TPM_HEADER_SIZE)
+ return -EIO;
+
+ if (offset > PAGE_SIZE)
+ return -EIO;
+
+ if (offset + count > PAGE_SIZE)
+ return -EIO;
+
+ /* Wait for completion of any existing command or cancellation */
+ if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE,
+ chip->vendor.timeout_c, &chip->vendor.read_queue) < 0) {
+ vtpm_cancel(chip);
+ return -ETIME;
+ }
+
+ memcpy(offset + (u8 *)shr, buf, count);
+ shr->length = count;
+ barrier();
+ shr->state = VTPM_STATE_SUBMIT;
+ notify_remote_via_evtchn(priv->evtchn);
+
+ ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
+ duration = tpm_calc_ordinal_duration(chip, ordinal);
+
+ if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
+ &chip->vendor.read_queue) < 0) {
+ /* got a signal or timeout, try to cancel */
+ vtpm_cancel(chip);
+ return -ETIME;
+ }
+
+ return count;
+}
+
+static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+ struct tpm_private *priv = chip_get_private(chip);
+ struct vtpm_shared_page *shr = priv->shr;
+ unsigned int offset = sizeof(*shr) + 4*shr->nr_extra_pages;
+ size_t length = shr->length;
+
+ if (shr->state == VTPM_STATE_IDLE)
+ return -ECANCELED;
+
+ /* In theory the wait at the end of _send makes this one unnecessary */
+ if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT,
+ chip->vendor.timeout_c, &chip->vendor.read_queue) < 0) {
+ vtpm_cancel(chip);
+ return -ETIME;
+ }
+
+ if (offset > PAGE_SIZE)
+ return -EIO;
+
+ if (offset + length > PAGE_SIZE)
+ length = PAGE_SIZE - offset;
+
+ if (length > count)
+ length = count;
+
+ memcpy(buf, offset + (u8 *)shr, count);
+
+ return length;
+}
+
+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 DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
+static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
+
+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,
+ &dev_attr_durations.attr,
+ &dev_attr_timeouts.attr,
+ NULL,
+};
+
+static struct attribute_group vtpm_attr_grp = {
+ .attrs = vtpm_attrs
+};
+
+#define TPM_LONG_TIMEOUT (10 * 60 * HZ)
+
+static const struct tpm_vendor_specific tpm_vtpm = {
+ .status = vtpm_status,
+ .recv = vtpm_recv,
+ .send = vtpm_send,
+ .cancel = vtpm_cancel,
+ .req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
+ .req_complete_val = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
+ .req_canceled = VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED,
+ .attr_group = &vtpm_attr_grp,
+ .miscdev = {
+ .fops = &vtpm_ops,
+ },
+ .duration = {
+ TPM_LONG_TIMEOUT,
+ TPM_LONG_TIMEOUT,
+ TPM_LONG_TIMEOUT,
+ },
+};
+
+static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
+{
+ struct tpm_private *priv = dev_id;
+
+ switch (priv->shr->state) {
+ case VTPM_STATE_IDLE:
+ case VTPM_STATE_FINISH:
+ wake_up_interruptible(&priv->chip->vendor.read_queue);
+ break;
+ case VTPM_STATE_SUBMIT:
+ case VTPM_STATE_CANCEL:
+ default:
+ break;
+ }
+ return IRQ_HANDLED;
+}
+
+static int setup_chip(struct device *dev, struct tpm_private *priv)
+{
+ struct tpm_chip *chip;
+
+ chip = tpm_register_hardware(dev, &tpm_vtpm);
+ if (!chip)
+ return -ENODEV;
+
+ init_waitqueue_head(&chip->vendor.read_queue);
+
+ priv->chip = chip;
+ chip_set_private(chip, priv);
+
+ return 0;
+}
+
+static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
+{
+ struct xenbus_transaction xbt;
+ const char *message = NULL;
+ int rv;
+
+ priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
+ if (!priv->shr) {
+ xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
+ return -ENOMEM;
+ }
+
+ rv = xenbus_grant_ring(dev, virt_to_mfn(priv->shr));
+ if (rv < 0)
+ return rv;
+
+ priv->ring_ref = rv;
+
+ rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
+ if (rv)
+ return rv;
+
+ rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
+ "tpmif", priv);
+ if (rv <= 0) {
+ xenbus_dev_fatal(dev, rv, "allocating TPM irq");
+ return rv;
+ }
+ priv->chip->vendor.irq = rv;
+
+ again:
+ rv = xenbus_transaction_start(&xbt);
+ if (rv) {
+ xenbus_dev_fatal(dev, rv, "starting transaction");
+ return rv;
+ }
+
+ rv = xenbus_printf(xbt, dev->nodename,
+ "ring-ref", "%u", priv->ring_ref);
+ if (rv) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+
+ rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
+ priv->evtchn);
+ if (rv) {
+ message = "writing event-channel";
+ goto abort_transaction;
+ }
+
+ rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
+ if (rv) {
+ message = "writing feature-protocol-v2";
+ goto abort_transaction;
+ }
+
+ rv = xenbus_transaction_end(xbt, 0);
+ if (rv == -EAGAIN)
+ goto again;
+ if (rv) {
+ xenbus_dev_fatal(dev, rv, "completing transaction");
+ return rv;
+ }
+
+ xenbus_switch_state(dev, XenbusStateInitialised);
+
+ return 0;
+
+ abort_transaction:
+ xenbus_transaction_end(xbt, 1);
+ if (message)
+ xenbus_dev_error(dev, rv, "%s", message);
+
+ return rv;
+}
+
+static void ring_free(struct tpm_private *priv)
+{
+ if (priv->ring_ref)
+ gnttab_end_foreign_access(priv->ring_ref, 0,
+ (unsigned long)priv->shr);
+
+ if (priv->chip && priv->chip->vendor.irq)
+ unbind_from_irqhandler(priv->chip->vendor.irq, priv);
+
+ free_page((unsigned long)priv->shr);
+ kfree(priv);
+}
+
+static int tpmfront_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ struct tpm_private *priv;
+ int rv;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv) {
+ xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
+ return -ENOMEM;
+ }
+
+ rv = setup_chip(&dev->dev, priv);
+ if (rv) {
+ kfree(priv);
+ return rv;
+ }
+
+ rv = setup_ring(dev, priv);
+ if (rv) {
+ tpm_remove_hardware(&dev->dev);
+ ring_free(priv);
+ return rv;
+ }
+
+ tpm_get_timeouts(priv->chip);
+
+ dev_set_drvdata(&dev->dev, priv->chip);
+
+ return rv;
+}
+
+static int tpmfront_remove(struct xenbus_device *dev)
+{
+ struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
+ struct tpm_private *priv = chip_get_private(chip);
+ tpm_remove_hardware(&dev->dev);
+ ring_free(priv);
+ return 0;
+}
+
+static int tpmfront_resume(struct xenbus_device *dev)
+{
+ /* A suspend/resume/migrate will interrupt a vTPM anyway */
+ tpmfront_remove(dev);
+ return tpmfront_probe(dev, NULL);
+}
+
+static void backend_changed(struct xenbus_device *dev,
+ enum xenbus_state backend_state)
+{
+ int val;
+
+ switch (backend_state) {
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ if (xenbus_scanf(XBT_NIL, dev->otherend,
+ "feature-protocol-v2", "%d", &val) < 0)
+ val = 0;
+ if (!val) {
+ xenbus_dev_fatal(dev, -EINVAL,
+ "vTPM protocol 2 required");
+ return;
+ }
+ xenbus_switch_state(dev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosing:
+ case XenbusStateClosed:
+ device_unregister(&dev->dev);
+ xenbus_frontend_closed(dev);
+ break;
+ default:
+ break;
+ }
+}
+
+static const struct xenbus_device_id tpmfront_ids[] = {
+ { "vtpm" },
+ { "" }
+};
+MODULE_ALIAS("xen:vtpm");
+
+static DEFINE_XENBUS_DRIVER(tpmfront, ,
+ .probe = tpmfront_probe,
+ .remove = tpmfront_remove,
+ .resume = tpmfront_resume,
+ .otherend_changed = backend_changed,
+ );
+
+static int __init xen_tpmfront_init(void)
+{
+ if (!xen_domain())
+ return -ENODEV;
+
+ return xenbus_register_frontend(&tpmfront_driver);
+}
+module_init(xen_tpmfront_init);
+
+static void __exit xen_tpmfront_exit(void)
+{
+ xenbus_unregister_driver(&tpmfront_driver);
+}
+module_exit(xen_tpmfront_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/include/xen/interface/io/tpmif.h b/include/xen/interface/io/tpmif.h
new file mode 100644
index 0000000..92522a4
--- /dev/null
+++ b/include/xen/interface/io/tpmif.h
@@ -0,0 +1,50 @@
+/******************************************************************************
+ * tpmif.h
+ *
+ * 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
+ * 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.
+ *
+ */
+
+#ifndef __XEN_PUBLIC_IO_TPMIF_H__
+#define __XEN_PUBLIC_IO_TPMIF_H__
+
+enum vtpm_shared_page_state {
+ VTPM_STATE_IDLE, /* no contents / vTPM idle / cancel complete */
+ VTPM_STATE_SUBMIT, /* request ready / vTPM working */
+ VTPM_STATE_FINISH, /* response ready / vTPM idle */
+ VTPM_STATE_CANCEL, /* cancel requested / vTPM working */
+};
+/* The backend should only change state to IDLE or FINISH, while the
+ * frontend should only change to SUBMIT or CANCEL. */
+
+
+struct vtpm_shared_page {
+ uint32_t length; /* request/response length in bytes */
+
+ uint8_t state; /* enum vtpm_shared_page_state */
+ uint8_t locality; /* for the current request */
+ uint8_t pad;
+
+ uint8_t nr_extra_pages; /* extra pages for long packets; may be zero */
+ uint32_t extra_pages[0]; /* grant IDs; length in nr_extra_pages */
+};
+
+#endif
--
1.8.1.4
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