[PATCH v5 08/11] tpm: Driver for supporting multiple emulated TPMs

[PATCH v5 08/11] tpm: Driver for supporting multiple emulated TPMs

[Stefan Berger]

This patch implements a driver for supporting multiple emulated TPMs in a
system.

The driver implements a device /dev/vtpmx that is used to created
a client device pair /dev/tpmX (e.g., /dev/tpm10) and a server side that
is accessed using a file descriptor returned by an ioctl.
The device /dev/tpmX is the usual TPM device created by the core TPM
driver. Applications or kernel subsystems can send TPM commands to it
and the corresponding server-side file descriptor receives these
commands and delivers them to an emulated TPM.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
CC: linux-kernel@vger.kernel.org
CC: linux-doc@vger.kernel.org
CC: linux-api@vger.kernel.org
---
 drivers/char/tpm/Kconfig    |  10 +
 drivers/char/tpm/Makefile   |   1 +
 drivers/char/tpm/tpm_vtpm.c | 566 ++++++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/Kbuild   |   1 +
 include/uapi/linux/vtpm.h   |  41 ++++
 5 files changed, 619 insertions(+)
 create mode 100644 drivers/char/tpm/tpm_vtpm.c
 create mode 100644 include/uapi/linux/vtpm.h

diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 3b84a8b..4c4e843 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -122,5 +122,15 @@ config TCG_CRB
 	  from within Linux.  To compile this driver as a module, choose
 	  M here; the module will be called tpm_crb.
 
+config TCG_VTPM
+	tristate "VTPM Interface"
+	depends on TCG_TPM
+	---help---
+	  This driver supports an emulated TPM (vTPM) running in userspace.
+	  A device /dev/vtpmx is provided that creates a device pair
+	  /dev/vtpmX and a server-side file descriptor on which the vTPM
+	  can receive commands.
+
+
 source "drivers/char/tpm/st33zp24/Kconfig"
 endif # TCG_TPM
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 56e8f1f..1a409c57 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_TCG_IBMVTPM) += tpm_ibmvtpm.o
 obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/
 obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
 obj-$(CONFIG_TCG_CRB) += tpm_crb.o
+obj-$(CONFIG_TCG_VTPM) += tpm_vtpm.o
diff --git a/drivers/char/tpm/tpm_vtpm.c b/drivers/char/tpm/tpm_vtpm.c
new file mode 100644
index 0000000..245ce91
--- /dev/null
+++ b/drivers/char/tpm/tpm_vtpm.c
@@ -0,0 +1,566 @@
+/*
+ * Copyright (C) 2015, 2016 IBM Corporation
+ *
+ * Author: Stefan Berger <stefanb@us.ibm.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * Device driver for vTPM.
+ *
+ * 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/types.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <linux/miscdevice.h>
+#include <linux/vtpm.h>
+#include <linux/file.h>
+#include <linux/anon_inodes.h>
+#include <linux/poll.h>
+#include <linux/compat.h>
+
+#include "tpm.h"
+
+#define VTPM_REQ_COMPLETE_FLAG  BIT(0)
+
+struct vtpm_dev {
+	struct tpm_chip *chip;
+
+	u32 flags;                   /* public API flags */
+
+	wait_queue_head_t wq;
+
+	struct mutex buf_lock;       /* protect buffer and flags */
+
+	long state;                  /* internal state */
+#define STATE_OPENED_FLAG        BIT(0)
+#define STATE_WAIT_RESPONSE_FLAG BIT(1)  /* waiting for emulator response */
+
+	size_t req_len;              /* length of queued TPM request */
+	size_t resp_len;             /* length of queued TPM response */
+	u8 buffer[TPM_BUFSIZE];      /* request/response buffer */
+};
+
+
+static void vtpm_delete_device(struct vtpm_dev *vtpm_dev);
+
+/*
+ * Functions related to 'server side'
+ */
+
+/**
+ * vtpm_fops_read - Read TPM commands on 'server side'
+ *
+ * Return value:
+ *	Number of bytes read or negative error code
+ */
+static ssize_t vtpm_fops_read(struct file *filp, char __user *buf,
+			      size_t count, loff_t *off)
+{
+	struct vtpm_dev *vtpm_dev = filp->private_data;
+	size_t len;
+	int sig, rc;
+
+	sig = wait_event_interruptible(vtpm_dev->wq, vtpm_dev->req_len != 0);
+	if (sig)
+		return -EINTR;
+
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	len = vtpm_dev->req_len;
+
+	if (count < len) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		pr_debug("Invalid size in recv: count=%zd, req_len=%zd\n",
+			 count, len);
+		return -EIO;
+	}
+
+	rc = copy_to_user(buf, vtpm_dev->buffer, len);
+	memset(vtpm_dev->buffer, 0, len);
+	vtpm_dev->req_len = 0;
+
+	if (!rc)
+		vtpm_dev->state |= STATE_WAIT_RESPONSE_FLAG;
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	if (rc)
+		return -EFAULT;
+
+	return len;
+}
+
+/**
+ * vtpm_fops_write - Write TPM responses on 'server side'
+ *
+ * Return value:
+ *	Number of bytes read or negative error value
+ */
+static ssize_t vtpm_fops_write(struct file *filp, const char __user *buf,
+			       size_t count, loff_t *off)
+{
+	struct vtpm_dev *vtpm_dev = filp->private_data;
+
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	if (count > sizeof(vtpm_dev->buffer) ||
+	    !(vtpm_dev->state & STATE_WAIT_RESPONSE_FLAG)) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		return -EIO;
+	}
+
+	vtpm_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
+
+	vtpm_dev->req_len = 0;
+
+	if (copy_from_user(vtpm_dev->buffer, buf, count)) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		return -EFAULT;
+	}
+
+	vtpm_dev->resp_len = count;
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	wake_up_interruptible(&vtpm_dev->wq);
+
+	return count;
+}
+
+/*
+ * vtpm_fops_poll: Poll status on 'server side'
+ *
+ * Return value:
+ *      Poll flags
+ */
+static unsigned int vtpm_fops_poll(struct file *filp, poll_table *wait)
+{
+	struct vtpm_dev *vtpm_dev = filp->private_data;
+	unsigned ret;
+
+	poll_wait(filp, &vtpm_dev->wq, wait);
+
+	ret = POLLOUT;
+
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	if (vtpm_dev->req_len)
+		ret |= POLLIN | POLLRDNORM;
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	return ret;
+}
+
+/*
+ * vtpm_fops_open - Open vTPM device on 'server side'
+ *
+ * Called when setting up the anonymous file descriptor
+ */
+static void vtpm_fops_open(struct file *filp)
+{
+	struct vtpm_dev *vtpm_dev = filp->private_data;
+
+	vtpm_dev->state |= STATE_OPENED_FLAG;
+}
+
+/**
+ * vtpm_fops_undo_open - counter-part to vtpm_fops_open
+ *
+ * Call to undo vtpm_fops_open
+ */
+static void vtpm_fops_undo_open(struct vtpm_dev *vtpm_dev)
+{
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	vtpm_dev->state &= ~STATE_OPENED_FLAG;
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	/* no more TPM responses -- wake up anyone waiting for them */
+	wake_up_interruptible(&vtpm_dev->wq);
+}
+
+/*
+ * vtpm_fops_release: Close 'server side'
+ *
+ * Return value:
+ *      Always returns 0.
+ */
+static int vtpm_fops_release(struct inode *inode, struct file *filp)
+{
+	struct vtpm_dev *vtpm_dev = filp->private_data;
+
+	filp->private_data = NULL;
+
+	vtpm_delete_device(vtpm_dev);
+
+	return 0;
+}
+
+static const struct file_operations vtpm_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.read = vtpm_fops_read,
+	.write = vtpm_fops_write,
+	.poll = vtpm_fops_poll,
+	.release = vtpm_fops_release,
+};
+
+/*
+ * Functions invoked by the core TPM driver to send TPM commands to
+ * 'server side' and receive responses from there.
+ */
+
+/*
+ * Called when core TPM driver reads TPM responses from 'server side'
+ *
+ * Return value:
+ *      Number of TPM response bytes read, negative error value otherwise
+ */
+static int vtpm_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	struct vtpm_dev *vtpm_dev = chip->vendor.priv;
+	size_t len;
+
+	if (!vtpm_dev)
+		return -EIO;
+
+	/* process gone ? */
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	if (!(vtpm_dev->state & STATE_OPENED_FLAG)) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		return -EPIPE;
+	}
+
+	len = vtpm_dev->resp_len;
+	if (count < len) {
+		dev_err(&chip->dev,
+			"Invalid size in recv: count=%zd, resp_len=%zd\n",
+			count, len);
+		len = -EIO;
+		goto out;
+	}
+
+	memcpy(buf, vtpm_dev->buffer, len);
+	vtpm_dev->resp_len = 0;
+
+out:
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	return len;
+}
+
+/*
+ * Called when core TPM driver forwards TPM requests to 'server side'.
+ *
+ * Return value:
+ *      0 in case of success, negative error value otherwise.
+ */
+static int vtpm_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	struct vtpm_dev *vtpm_dev = chip->vendor.priv;
+	int rc = 0;
+
+	if (!vtpm_dev)
+		return -EIO;
+
+	if (count > sizeof(vtpm_dev->buffer)) {
+		dev_err(&chip->dev,
+			"Invalid size in send: count=%zd, buffer size=%zd\n",
+			count, sizeof(vtpm_dev->buffer));
+		return -EIO;
+	}
+
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	if (!(vtpm_dev->state & STATE_OPENED_FLAG)) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		return -EPIPE;
+	}
+
+	vtpm_dev->resp_len = 0;
+
+	vtpm_dev->req_len = count;
+	memcpy(vtpm_dev->buffer, buf, count);
+
+	vtpm_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	wake_up_interruptible(&vtpm_dev->wq);
+
+	return rc;
+}
+
+static void vtpm_tpm_op_cancel(struct tpm_chip *chip)
+{
+	/* not supported */
+}
+
+static u8 vtpm_tpm_op_status(struct tpm_chip *chip)
+{
+	struct vtpm_dev *vtpm_dev = chip->vendor.priv;
+
+	if (vtpm_dev->resp_len)
+		return VTPM_REQ_COMPLETE_FLAG;
+
+	return 0;
+}
+
+static bool vtpm_tpm_req_canceled(struct tpm_chip  *chip, u8 status)
+{
+	struct vtpm_dev *vtpm_dev = chip->vendor.priv;
+	bool ret;
+
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	ret = !(vtpm_dev->state & STATE_OPENED_FLAG);
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
+	return ret;
+}
+
+static const struct tpm_class_ops vtpm_tpm_ops = {
+	.recv = vtpm_tpm_op_recv,
+	.send = vtpm_tpm_op_send,
+	.cancel = vtpm_tpm_op_cancel,
+	.status = vtpm_tpm_op_status,
+	.req_complete_mask = VTPM_REQ_COMPLETE_FLAG,
+	.req_complete_val = VTPM_REQ_COMPLETE_FLAG,
+	.req_canceled = vtpm_tpm_req_canceled,
+};
+
+/*
+ * Code related to creation and deletion of device pairs
+ */
+static struct vtpm_dev *vtpm_create_vtpm_dev(void)
+{
+	struct vtpm_dev *vtpm_dev;
+	struct tpm_chip *chip;
+	int err;
+
+	vtpm_dev = kzalloc(sizeof(*vtpm_dev), GFP_KERNEL);
+	if (vtpm_dev == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	init_waitqueue_head(&vtpm_dev->wq);
+	mutex_init(&vtpm_dev->buf_lock);
+
+	chip = tpm_chip_alloc(NULL, &vtpm_tpm_ops);
+	if (IS_ERR(chip)) {
+		err = PTR_ERR(chip);
+		goto err_vtpm_dev_free;
+	}
+	chip->vendor.priv = vtpm_dev;
+
+	vtpm_dev->chip = chip;
+
+	return vtpm_dev;
+
+err_vtpm_dev_free:
+	kfree(vtpm_dev);
+
+	return ERR_PTR(err);
+}
+
+/*
+ * Undo what has been done in vtpm_create_vtpm_dev
+ */
+static inline void vtpm_delete_vtpm_dev(struct vtpm_dev *vtpm_dev)
+{
+	put_device(&vtpm_dev->chip->dev); /* frees chip */
+	kfree(vtpm_dev);
+}
+
+/*
+ * Create a /dev/tpm%d and 'server side' file descriptor pair
+ *
+ * Return value:
+ *      Returns file pointer on success, an error value otherwise
+ */
+static struct file *vtpm_create_device(
+				       struct vtpm_new_dev *vtpm_new_dev)
+{
+	struct vtpm_dev *vtpm_dev;
+	int rc, fd;
+	struct file *file;
+
+	if (vtpm_new_dev->flags & ~VTPM_FLAGS_ALL)
+		return ERR_PTR(-ENOSYS);
+
+	vtpm_dev = vtpm_create_vtpm_dev();
+	if (IS_ERR(vtpm_dev))
+		return ERR_CAST(vtpm_dev);
+
+	vtpm_dev->flags = vtpm_new_dev->flags;
+
+	/* setup an anonymous file for the server-side */
+	fd = get_unused_fd_flags(O_RDWR);
+	if (fd < 0) {
+		rc = fd;
+		goto err_delete_vtpm_dev;
+	}
+
+	file = anon_inode_getfile("[vtpms]", &vtpm_fops, vtpm_dev, O_RDWR);
+	if (IS_ERR(file)) {
+		rc = PTR_ERR(file);
+		goto err_put_unused_fd;
+	}
+
+	/* from now on we can unwind with put_unused_fd() + fput() */
+	/* simulate an open() on the server side */
+	vtpm_fops_open(file);
+
+	if (vtpm_dev->flags & VTPM_FLAG_TPM2)
+		vtpm_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;
+
+	rc = tpm_chip_register(vtpm_dev->chip);
+	if (rc)
+		goto err_vtpm_fput;
+
+	vtpm_new_dev->fd = fd;
+	vtpm_new_dev->major = MAJOR(vtpm_dev->chip->dev.devt);
+	vtpm_new_dev->minor = MINOR(vtpm_dev->chip->dev.devt);
+	vtpm_new_dev->dev_num = vtpm_dev->chip->dev_num;
+
+	return file;
+
+err_vtpm_fput:
+	put_unused_fd(fd);
+	fput(file);
+
+	return ERR_PTR(rc);
+
+err_put_unused_fd:
+	put_unused_fd(fd);
+
+err_delete_vtpm_dev:
+	vtpm_delete_vtpm_dev(vtpm_dev);
+
+	return ERR_PTR(rc);
+}
+
+/*
+ * Counter part to vtpm_create_device.
+ */
+static void vtpm_delete_device(struct vtpm_dev *vtpm_dev)
+{
+	tpm_chip_unregister(vtpm_dev->chip);
+
+	vtpm_fops_undo_open(vtpm_dev);
+
+	vtpm_delete_vtpm_dev(vtpm_dev);
+}
+
+/*
+ * Code related to the control device /dev/vtpmx
+ */
+
+/*
+ * vtpmx_fops_ioctl: ioctl on /dev/vtpmx
+ *
+ * Return value:
+ *      Returns 0 on success, a negative error code otherwise.
+ */
+static long vtpmx_fops_ioctl(struct file *f, unsigned int ioctl,
+			    unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	struct vtpm_new_dev *vtpm_new_dev_p;
+	struct vtpm_new_dev vtpm_new_dev;
+	struct file *file;
+
+	switch (ioctl) {
+	case VTPM_NEW_DEV:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		vtpm_new_dev_p = argp;
+		if (copy_from_user(&vtpm_new_dev, vtpm_new_dev_p,
+				   sizeof(vtpm_new_dev)))
+			return -EFAULT;
+		file = vtpm_create_device(&vtpm_new_dev);
+		if (IS_ERR(file))
+			return PTR_ERR(file);
+		if (copy_to_user(vtpm_new_dev_p, &vtpm_new_dev,
+				 sizeof(vtpm_new_dev))) {
+			put_unused_fd(vtpm_new_dev.fd);
+			fput(file);
+			return -EFAULT;
+		}
+
+		fd_install(vtpm_new_dev.fd, file);
+		return 0;
+
+	default:
+		return -ENOSYS;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static long vtpmx_fops_compat_ioctl(struct file *f, unsigned int ioctl,
+				    unsigned long arg)
+{
+	return vtpmx_fops_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations vtpmx_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = vtpmx_fops_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = vtpmx_fops_compat_ioctl,
+#endif
+	.llseek = noop_llseek,
+};
+
+static struct miscdevice vtpmx_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "vtpmx",
+	.fops = &vtpmx_fops,
+};
+
+static int vtpmx_init(void)
+{
+	return misc_register(&vtpmx_miscdev);
+}
+
+static void vtpmx_cleanup(void)
+{
+	misc_deregister(&vtpmx_miscdev);
+}
+
+static int __init vtpm_module_init(void)
+{
+	int rc;
+
+	rc = vtpmx_init();
+	if (rc) {
+		pr_err("couldn't create vtpmx device\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static void __exit vtpm_module_exit(void)
+{
+	vtpmx_cleanup();
+}
+
+module_init(vtpm_module_init);
+module_exit(vtpm_module_exit);
+
+MODULE_AUTHOR("Stefan Berger (stefanb@us.ibm.com)");
+MODULE_DESCRIPTION("vTPM Driver");
+MODULE_VERSION("0.1");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index ebd10e6..3a602c9 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -449,6 +449,7 @@ header-y += virtio_scsi.h
 header-y += virtio_types.h
 header-y += vm_sockets.h
 header-y += vt.h
+header-y += vtpm.h
 header-y += wait.h
 header-y += wanrouter.h
 header-y += watchdog.h
diff --git a/include/uapi/linux/vtpm.h b/include/uapi/linux/vtpm.h
new file mode 100644
index 0000000..4adc486
--- /dev/null
+++ b/include/uapi/linux/vtpm.h
@@ -0,0 +1,41 @@
+/*
+ * Definitions for the VTPM interface
+ * Copyright (c) 2015, 2016, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _UAPI_LINUX_VTPM_H
+#define _UAPI_LINUX_VTPM_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+/* ioctls */
+
+struct vtpm_new_dev {
+	__u32 flags;         /* input */
+	__u32 dev_num;       /* output */
+	__u32 fd;            /* output */
+	__u32 major;         /* output */
+	__u32 minor;         /* output */
+};
+
+/* above flags */
+#define VTPM_FLAG_TPM2           1  /* emulator is TPM 2 */
+
+/* all supported flags */
+#define VTPM_FLAGS_ALL  (VTPM_FLAG_TPM2)
+
+#define VTPM_TPM 0xa0
+
+#define VTPM_NEW_DEV         _IOW(VTPM_TPM, 0x00, struct vtpm_new_dev)
+
+#endif /* _UAPI_LINUX_VTPM_H */
-- 
2.4.3

[PATCH v5 09/11] tpm: Initialize TPM and get durations and timeouts

[Stefan Berger]

Add the retrieval of TPM 1.2 durations and timeouts. Since this requires
the startup of the TPM, do this for TPM 1.2 and TPM 2.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
CC: linux-kernel@vger.kernel.org
CC: linux-doc@vger.kernel.org
CC: linux-api@vger.kernel.org
---
 drivers/char/tpm/tpm_vtpm.c | 94 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 85 insertions(+), 9 deletions(-)

diff --git a/drivers/char/tpm/tpm_vtpm.c b/drivers/char/tpm/tpm_vtpm.c
index 245ce91..b048898 100644
--- a/drivers/char/tpm/tpm_vtpm.c
+++ b/drivers/char/tpm/tpm_vtpm.c
@@ -45,8 +45,11 @@ struct vtpm_dev {
 	size_t req_len;              /* length of queued TPM request */
 	size_t resp_len;             /* length of queued TPM response */
 	u8 buffer[TPM_BUFSIZE];      /* request/response buffer */
+
+	struct work_struct work;     /* task that retrieves TPM timeouts */
 };
 
+static struct workqueue_struct *workqueue;
 
 static void vtpm_delete_device(struct vtpm_dev *vtpm_dev);
 
@@ -67,6 +70,15 @@ static ssize_t vtpm_fops_read(struct file *filp, char __user *buf,
 	size_t len;
 	int sig, rc;
 
+	mutex_lock(&vtpm_dev->buf_lock);
+
+	if (!(vtpm_dev->state & STATE_OPENED_FLAG)) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		return -EPIPE;
+	}
+
+	mutex_unlock(&vtpm_dev->buf_lock);
+
 	sig = wait_event_interruptible(vtpm_dev->wq, vtpm_dev->req_len != 0);
 	if (sig)
 		return -EINTR;
@@ -110,6 +122,11 @@ static ssize_t vtpm_fops_write(struct file *filp, const char __user *buf,
 
 	mutex_lock(&vtpm_dev->buf_lock);
 
+	if (!(vtpm_dev->state & STATE_OPENED_FLAG)) {
+		mutex_unlock(&vtpm_dev->buf_lock);
+		return -EPIPE;
+	}
+
 	if (count > sizeof(vtpm_dev->buffer) ||
 	    !(vtpm_dev->state & STATE_WAIT_RESPONSE_FLAG)) {
 		mutex_unlock(&vtpm_dev->buf_lock);
@@ -154,6 +171,9 @@ static unsigned int vtpm_fops_poll(struct file *filp, poll_table *wait)
 	if (vtpm_dev->req_len)
 		ret |= POLLIN | POLLRDNORM;
 
+	if (!(vtpm_dev->state & STATE_OPENED_FLAG))
+		ret |= POLLHUP;
+
 	mutex_unlock(&vtpm_dev->buf_lock);
 
 	return ret;
@@ -341,6 +361,54 @@ static const struct tpm_class_ops vtpm_tpm_ops = {
 };
 
 /*
+ * Code related to the startup of the TPM 2 and startup of TPM 1.2 +
+ * retrieval of timeouts and durations.
+ */
+
+static void vtpm_dev_work(struct work_struct *work)
+{
+	struct vtpm_dev *vtpm_dev = container_of(work, struct vtpm_dev, work);
+	int rc;
+
+	if (vtpm_dev->flags & VTPM_FLAG_TPM2)
+		rc = tpm2_startup(vtpm_dev->chip, TPM2_SU_CLEAR);
+	else
+		rc = tpm_get_timeouts(vtpm_dev->chip);
+
+	if (rc)
+		goto err;
+
+	rc = tpm_chip_register(vtpm_dev->chip);
+	if (rc)
+		goto err;
+
+	return;
+
+err:
+	vtpm_fops_undo_open(vtpm_dev);
+}
+
+/*
+ * vtpm_dev_work_stop: make sure the work has finished
+ *
+ * This function is useful when user space closed the fd
+ * while the driver still determines timeouts.
+ */
+static void vtpm_dev_work_stop(struct vtpm_dev *vtpm_dev)
+{
+	vtpm_fops_undo_open(vtpm_dev);
+	flush_work(&vtpm_dev->work);
+}
+
+/*
+ * vtpm_dev_work_start: Schedule the work for TPM 1.2 & 2 initialization
+ */
+static inline void vtpm_dev_work_start(struct vtpm_dev *vtpm_dev)
+{
+	queue_work(workqueue, &vtpm_dev->work);
+}
+
+/*
  * Code related to creation and deletion of device pairs
  */
 static struct vtpm_dev *vtpm_create_vtpm_dev(void)
@@ -355,6 +423,7 @@ static struct vtpm_dev *vtpm_create_vtpm_dev(void)
 
 	init_waitqueue_head(&vtpm_dev->wq);
 	mutex_init(&vtpm_dev->buf_lock);
+	INIT_WORK(&vtpm_dev->work, vtpm_dev_work);
 
 	chip = tpm_chip_alloc(NULL, &vtpm_tpm_ops);
 	if (IS_ERR(chip)) {
@@ -424,9 +493,7 @@ static struct file *vtpm_create_device(
 	if (vtpm_dev->flags & VTPM_FLAG_TPM2)
 		vtpm_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;
 
-	rc = tpm_chip_register(vtpm_dev->chip);
-	if (rc)
-		goto err_vtpm_fput;
+	vtpm_dev_work_start(vtpm_dev);
 
 	vtpm_new_dev->fd = fd;
 	vtpm_new_dev->major = MAJOR(vtpm_dev->chip->dev.devt);
@@ -435,12 +502,6 @@ static struct file *vtpm_create_device(
 
 	return file;
 
-err_vtpm_fput:
-	put_unused_fd(fd);
-	fput(file);
-
-	return ERR_PTR(rc);
-
 err_put_unused_fd:
 	put_unused_fd(fd);
 
@@ -455,6 +516,8 @@ err_delete_vtpm_dev:
  */
 static void vtpm_delete_device(struct vtpm_dev *vtpm_dev)
 {
+	vtpm_dev_work_stop(vtpm_dev);
+
 	tpm_chip_unregister(vtpm_dev->chip);
 
 	vtpm_fops_undo_open(vtpm_dev);
@@ -549,11 +612,24 @@ static int __init vtpm_module_init(void)
 		return rc;
 	}
 
+	workqueue = create_workqueue("tpm-vtpm");
+	if (!workqueue) {
+		pr_err("couldn't create workqueue\n");
+		rc = -ENOMEM;
+		goto err_vtpmx_cleanup;
+	}
+
 	return 0;
+
+err_vtpmx_cleanup:
+	vtpmx_cleanup();
+
+	return rc;
 }
 
 static void __exit vtpm_module_exit(void)
 {
+	destroy_workqueue(workqueue);
 	vtpmx_cleanup();
 }
 
-- 
2.4.3

[PATCH v5 10/11] tpm: Add documentation for the tpm_vtpm device driver

[Stefan Berger]

Add documentation for the tpm_vtpm device driver that implements
support for providing TPM functionality to Linux containers.

Parts of this documentation were recycled from the Xen vTPM
device driver documentation.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
CC: linux-kernel@vger.kernel.org
CC: linux-doc@vger.kernel.org
CC: linux-api@vger.kernel.org
---
 Documentation/tpm/tpm_vtpm.txt | 53 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Documentation/tpm/tpm_vtpm.txt

diff --git a/Documentation/tpm/tpm_vtpm.txt b/Documentation/tpm/tpm_vtpm.txt
new file mode 100644
index 0000000..7746c0d
--- /dev/null
+++ b/Documentation/tpm/tpm_vtpm.txt
@@ -0,0 +1,53 @@
+Virtual TPM Device Driver for Linux Containers
+
+Authors: Stefan Berger (IBM)
+
+This document describes the virtual Trusted Platform Module (vTPM) device
+driver for Linux containers.
+
+INTRODUCTION
+------------
+
+The goal of this work is to provide TPM functionality to each Linux
+container. This allows programs to interact with a TPM in a container
+the same way they interact with a TPM on the physical system. Each
+container gets its own unique, emulated, software TPM.
+
+
+DESIGN
+------
+
+To make an emulated software TPM available to each container, the container
+management stack needs to create a device pair consisting of a client TPM
+character device /dev/tpmX (with X=0,1,2...) and a 'server side' file
+descriptor. The former is moved into the container by creating a character
+device with the appropriate major and minor numbers while the file descriptor
+is passed to the TPM emulator. Software inside the container can then send
+TPM commands using the character device and the emulator will receive the
+commands via the file descriptor and use it for sending back responses.
+
+To support this, the virtual TPM device driver provides a device /dev/vtpmx
+that is used to create device pairs using an ioctl. The ioctl takes as
+an input flags for configuring the device. The flags  for example indicate
+whether TPM 1.2 or TPM 2 functionality is supported by the TPM emulator.
+The result of the ioctl are the file descriptor for the 'server side'
+as well as the major and minor numbers of the character device that was created.
+Besides that the number of the TPM character device is return. If for
+example /dev/tpm10 was created, the number (dev_num) 10 is returned.
+
+The following is the data structure of the VTPM_NEW_DEV ioctl:
+
+struct vtpm_new_dev {
+	__u32 flags;         /* input */
+	__u32 dev_num;       /* output */
+	__u32 fd;            /* output */
+	__u32 major;         /* output */
+	__u32 minor;         /* output */
+};
+
+Note that if unsupported flags are passed to the device driver, the ioctl will
+fail and errno will be set to ENOSYS. Similarly, if an unsupported ioctl is
+called on the device driver, the ioctl will fail and errno will be set to ENOSYS.
+
+See /usr/include/linux/vtpm.h for definitions related to the public interface
+of this vTPM device driver.
-- 
2.4.3