437 lines
9.7 KiB
C
437 lines
9.7 KiB
C
/*
|
|
* Implementation of the Xen vTPM device frontend
|
|
*
|
|
* Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
|
|
*
|
|
* 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.
|
|
*/
|
|
#include <linux/errno.h>
|
|
#include <linux/err.h>
|
|
#include <linux/interrupt.h>
|
|
#include <xen/xen.h>
|
|
#include <xen/events.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 = TPM_VPRIV(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: /* cancel requested, not yet canceled */
|
|
return VTPM_STATUS_RUNNING;
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
|
|
{
|
|
return status & VTPM_STATUS_CANCELED;
|
|
}
|
|
|
|
static void vtpm_cancel(struct tpm_chip *chip)
|
|
{
|
|
struct tpm_private *priv = TPM_VPRIV(chip);
|
|
priv->shr->state = VTPM_STATE_CANCEL;
|
|
wmb();
|
|
notify_remote_via_evtchn(priv->evtchn);
|
|
}
|
|
|
|
static unsigned int shr_data_offset(struct vtpm_shared_page *shr)
|
|
{
|
|
return sizeof(*shr) + sizeof(u32) * shr->nr_extra_pages;
|
|
}
|
|
|
|
static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
|
|
{
|
|
struct tpm_private *priv = TPM_VPRIV(chip);
|
|
struct vtpm_shared_page *shr = priv->shr;
|
|
unsigned int offset = shr_data_offset(shr);
|
|
|
|
u32 ordinal;
|
|
unsigned long duration;
|
|
|
|
if (offset > PAGE_SIZE)
|
|
return -EINVAL;
|
|
|
|
if (offset + count > PAGE_SIZE)
|
|
return -EINVAL;
|
|
|
|
/* 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, true) < 0) {
|
|
vtpm_cancel(chip);
|
|
return -ETIME;
|
|
}
|
|
|
|
memcpy(offset + (u8 *)shr, buf, count);
|
|
shr->length = count;
|
|
barrier();
|
|
shr->state = VTPM_STATE_SUBMIT;
|
|
wmb();
|
|
notify_remote_via_evtchn(priv->evtchn);
|
|
|
|
ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal);
|
|
duration = tpm_calc_ordinal_duration(chip, ordinal);
|
|
|
|
if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
|
|
&chip->vendor.read_queue, true) < 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 = TPM_VPRIV(chip);
|
|
struct vtpm_shared_page *shr = priv->shr;
|
|
unsigned int offset = shr_data_offset(shr);
|
|
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, true) < 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, length);
|
|
|
|
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,
|
|
};
|
|
|
|
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_req_canceled,
|
|
.attr_group = &vtpm_attr_grp,
|
|
.miscdev = {
|
|
.fops = &vtpm_ops,
|
|
},
|
|
};
|
|
|
|
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;
|
|
TPM_VPRIV(chip) = priv;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* caller must clean up in case of errors */
|
|
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)
|
|
return;
|
|
|
|
if (priv->ring_ref)
|
|
gnttab_end_foreign_access(priv->ring_ref, 0,
|
|
(unsigned long)priv->shr);
|
|
else
|
|
free_page((unsigned long)priv->shr);
|
|
|
|
if (priv->chip && priv->chip->vendor.irq)
|
|
unbind_from_irqhandler(priv->chip->vendor.irq, priv);
|
|
|
|
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);
|
|
|
|
return rv;
|
|
}
|
|
|
|
static int tpmfront_remove(struct xenbus_device *dev)
|
|
{
|
|
struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
|
|
struct tpm_private *priv = TPM_VPRIV(chip);
|
|
tpm_remove_hardware(&dev->dev);
|
|
ring_free(priv);
|
|
TPM_VPRIV(chip) = NULL;
|
|
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 (dev->state == XenbusStateConnected)
|
|
break;
|
|
|
|
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_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
|
|
MODULE_DESCRIPTION("Xen vTPM Driver");
|
|
MODULE_LICENSE("GPL");
|