KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1171 insertions, 0 deletions

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
new file mode 100644
index 000000000..d32fa4b50
--- /dev/null
+++ b/drivers/input/misc/uinput.c
@@ -0,0 +1,1171 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  User level driver support for input subsystem
+ *
+ * Heavily based on evdev.c by Vojtech Pavlik
+ *
+ * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
+ *
+ * Changes/Revisions:
+ *	0.4	01/09/2014 (Benjamin Tissoires <benjamin.tissoires@redhat.com>)
+ *		- add UI_GET_SYSNAME ioctl
+ *	0.3	09/04/2006 (Anssi Hannula <anssi.hannula@gmail.com>)
+ *		- updated ff support for the changes in kernel interface
+ *		- added MODULE_VERSION
+ *	0.2	16/10/2004 (Micah Dowty <micah@navi.cx>)
+ *		- added force feedback support
+ *              - added UI_SET_PHYS
+ *	0.1	20/06/2002
+ *		- first public version
+ */
+#include <uapi/linux/uinput.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/lockdep.h>
+#include <linux/miscdevice.h>
+#include <linux/overflow.h>
+#include <linux/spinlock.h>
+#include <linux/input/mt.h>
+#include "../input-compat.h"
+
+#define UINPUT_NAME		"uinput"
+#define UINPUT_BUFFER_SIZE	16
+#define UINPUT_NUM_REQUESTS	16
+#define UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS 10
+
+enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };
+
+struct uinput_request {
+	unsigned int		id;
+	unsigned int		code;	/* UI_FF_UPLOAD, UI_FF_ERASE */
+
+	int			retval;
+	struct completion	done;
+
+	union {
+		unsigned int	effect_id;
+		struct {
+			struct ff_effect *effect;
+			struct ff_effect *old;
+		} upload;
+	} u;
+};
+
+struct uinput_device {
+	struct input_dev	*dev;
+	struct mutex		mutex;
+	enum uinput_state	state;
+	spinlock_t		state_lock;
+	wait_queue_head_t	waitq;
+	unsigned char		ready;
+	unsigned char		head;
+	unsigned char		tail;
+	struct input_event	buff[UINPUT_BUFFER_SIZE];
+	unsigned int		ff_effects_max;
+
+	struct uinput_request	*requests[UINPUT_NUM_REQUESTS];
+	wait_queue_head_t	requests_waitq;
+	spinlock_t		requests_lock;
+};
+
+static int uinput_dev_event(struct input_dev *dev,
+			    unsigned int type, unsigned int code, int value)
+{
+	struct uinput_device	*udev = input_get_drvdata(dev);
+	struct timespec64	ts;
+
+	lockdep_assert_held(&dev->event_lock);
+
+	ktime_get_ts64(&ts);
+
+	udev->buff[udev->head] = (struct input_event) {
+		.input_event_sec = ts.tv_sec,
+		.input_event_usec = ts.tv_nsec / NSEC_PER_USEC,
+		.type = type,
+		.code = code,
+		.value = value,
+	};
+
+	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
+
+	wake_up_interruptible(&udev->waitq);
+
+	return 0;
+}
+
+/* Atomically allocate an ID for the given request. Returns 0 on success. */
+static bool uinput_request_alloc_id(struct uinput_device *udev,
+				    struct uinput_request *request)
+{
+	unsigned int id;
+	bool reserved = false;
+
+	spin_lock(&udev->requests_lock);
+
+	for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
+		if (!udev->requests[id]) {
+			request->id = id;
+			udev->requests[id] = request;
+			reserved = true;
+			break;
+		}
+	}
+
+	spin_unlock(&udev->requests_lock);
+	return reserved;
+}
+
+static struct uinput_request *uinput_request_find(struct uinput_device *udev,
+						  unsigned int id)
+{
+	/* Find an input request, by ID. Returns NULL if the ID isn't valid. */
+	if (id >= UINPUT_NUM_REQUESTS)
+		return NULL;
+
+	return udev->requests[id];
+}
+
+static int uinput_request_reserve_slot(struct uinput_device *udev,
+				       struct uinput_request *request)
+{
+	/* Allocate slot. If none are available right away, wait. */
+	return wait_event_interruptible(udev->requests_waitq,
+					uinput_request_alloc_id(udev, request));
+}
+
+static void uinput_request_release_slot(struct uinput_device *udev,
+					unsigned int id)
+{
+	/* Mark slot as available */
+	spin_lock(&udev->requests_lock);
+	udev->requests[id] = NULL;
+	spin_unlock(&udev->requests_lock);
+
+	wake_up(&udev->requests_waitq);
+}
+
+static int uinput_request_send(struct uinput_device *udev,
+			       struct uinput_request *request)
+{
+	unsigned long flags;
+	int retval = 0;
+
+	spin_lock(&udev->state_lock);
+
+	if (udev->state != UIST_CREATED) {
+		retval = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * Tell our userspace application about this new request
+	 * by queueing an input event.
+	 */
+	spin_lock_irqsave(&udev->dev->event_lock, flags);
+	uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
+	spin_unlock_irqrestore(&udev->dev->event_lock, flags);
+
+ out:
+	spin_unlock(&udev->state_lock);
+	return retval;
+}
+
+static int uinput_request_submit(struct uinput_device *udev,
+				 struct uinput_request *request)
+{
+	int retval;
+
+	/*
+	 * Initialize completion before allocating the request slot.
+	 * Once the slot is allocated, uinput_flush_requests() may
+	 * complete it at any time, so it must be initialized first.
+	 */
+	init_completion(&request->done);
+
+	retval = uinput_request_reserve_slot(udev, request);
+	if (retval)
+		return retval;
+
+	retval = uinput_request_send(udev, request);
+	if (retval)
+		goto out;
+
+	if (!wait_for_completion_timeout(&request->done, 30 * HZ)) {
+		retval = -ETIMEDOUT;
+		goto out;
+	}
+
+	retval = request->retval;
+
+ out:
+	uinput_request_release_slot(udev, request->id);
+	return retval;
+}
+
+/*
+ * Fail all outstanding requests so handlers don't wait for the userspace
+ * to finish processing them.
+ */
+static void uinput_flush_requests(struct uinput_device *udev)
+{
+	struct uinput_request *request;
+	int i;
+
+	spin_lock(&udev->requests_lock);
+
+	for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
+		request = udev->requests[i];
+		if (request) {
+			request->retval = -ENODEV;
+			complete(&request->done);
+		}
+	}
+
+	spin_unlock(&udev->requests_lock);
+}
+
+static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
+{
+	uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
+}
+
+static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
+{
+	uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
+}
+
+static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
+{
+	return uinput_dev_event(dev, EV_FF, effect_id, value);
+}
+
+static int uinput_dev_upload_effect(struct input_dev *dev,
+				    struct ff_effect *effect,
+				    struct ff_effect *old)
+{
+	struct uinput_device *udev = input_get_drvdata(dev);
+	struct uinput_request request;
+
+	/*
+	 * uinput driver does not currently support periodic effects with
+	 * custom waveform since it does not have a way to pass buffer of
+	 * samples (custom_data) to userspace. If ever there is a device
+	 * supporting custom waveforms we would need to define an additional
+	 * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
+	 */
+	if (effect->type == FF_PERIODIC &&
+			effect->u.periodic.waveform == FF_CUSTOM)
+		return -EINVAL;
+
+	request.code = UI_FF_UPLOAD;
+	request.u.upload.effect = effect;
+	request.u.upload.old = old;
+
+	return uinput_request_submit(udev, &request);
+}
+
+static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
+{
+	struct uinput_device *udev = input_get_drvdata(dev);
+	struct uinput_request request;
+
+	if (!test_bit(EV_FF, dev->evbit))
+		return -ENOSYS;
+
+	request.code = UI_FF_ERASE;
+	request.u.effect_id = effect_id;
+
+	return uinput_request_submit(udev, &request);
+}
+
+static int uinput_dev_flush(struct input_dev *dev, struct file *file)
+{
+	/*
+	 * If we are called with file == NULL that means we are tearing
+	 * down the device, and therefore we can not handle FF erase
+	 * requests: either we are handling UI_DEV_DESTROY (and holding
+	 * the udev->mutex), or the file descriptor is closed and there is
+	 * nobody on the other side anymore.
+	 */
+	return file ? input_ff_flush(dev, file) : 0;
+}
+
+static void uinput_destroy_device(struct uinput_device *udev)
+{
+	const char *name, *phys;
+	struct input_dev *dev = udev->dev;
+	enum uinput_state old_state = udev->state;
+
+	/*
+	 * Update state under state_lock so that concurrent
+	 * uinput_request_send() sees the state change before we
+	 * flush pending requests and tear down the device.
+	 */
+	spin_lock(&udev->state_lock);
+	udev->state = UIST_NEW_DEVICE;
+	spin_unlock(&udev->state_lock);
+
+	if (dev) {
+		name = dev->name;
+		phys = dev->phys;
+		if (old_state == UIST_CREATED) {
+			uinput_flush_requests(udev);
+			input_unregister_device(dev);
+		} else {
+			input_free_device(dev);
+		}
+		kfree(name);
+		kfree(phys);
+		udev->dev = NULL;
+	}
+}
+
+static int uinput_create_device(struct uinput_device *udev)
+{
+	struct input_dev *dev = udev->dev;
+	int error, nslot;
+
+	if (udev->state != UIST_SETUP_COMPLETE) {
+		printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
+		return -EINVAL;
+	}
+
+	if (test_bit(EV_ABS, dev->evbit)) {
+		input_alloc_absinfo(dev);
+		if (!dev->absinfo) {
+			error = -EINVAL;
+			goto fail1;
+		}
+
+		if (test_bit(ABS_MT_SLOT, dev->absbit)) {
+			nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
+			error = input_mt_init_slots(dev, nslot, 0);
+			if (error)
+				goto fail1;
+		} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
+			input_set_events_per_packet(dev, 60);
+		}
+	}
+
+	if (test_bit(EV_FF, dev->evbit) && !udev->ff_effects_max) {
+		printk(KERN_DEBUG "%s: ff_effects_max should be non-zero when FF_BIT is set\n",
+			UINPUT_NAME);
+		error = -EINVAL;
+		goto fail1;
+	}
+
+	if (udev->ff_effects_max) {
+		error = input_ff_create(dev, udev->ff_effects_max);
+		if (error)
+			goto fail1;
+
+		dev->ff->upload = uinput_dev_upload_effect;
+		dev->ff->erase = uinput_dev_erase_effect;
+		dev->ff->playback = uinput_dev_playback;
+		dev->ff->set_gain = uinput_dev_set_gain;
+		dev->ff->set_autocenter = uinput_dev_set_autocenter;
+		/*
+		 * The standard input_ff_flush() implementation does
+		 * not quite work for uinput as we can't reasonably
+		 * handle FF requests during device teardown.
+		 */
+		dev->flush = uinput_dev_flush;
+	}
+
+	dev->event = uinput_dev_event;
+
+	input_set_drvdata(udev->dev, udev);
+
+	error = input_register_device(udev->dev);
+	if (error)
+		goto fail2;
+
+	spin_lock(&udev->state_lock);
+	udev->state = UIST_CREATED;
+	spin_unlock(&udev->state_lock);
+
+	return 0;
+
+ fail2:	input_ff_destroy(dev);
+ fail1: uinput_destroy_device(udev);
+	return error;
+}
+
+static int uinput_open(struct inode *inode, struct file *file)
+{
+	struct uinput_device *newdev;
+
+	newdev = kzalloc_obj(*newdev);
+	if (!newdev)
+		return -ENOMEM;
+
+	mutex_init(&newdev->mutex);
+	spin_lock_init(&newdev->state_lock);
+	spin_lock_init(&newdev->requests_lock);
+	init_waitqueue_head(&newdev->requests_waitq);
+	init_waitqueue_head(&newdev->waitq);
+	newdev->state = UIST_NEW_DEVICE;
+
+	file->private_data = newdev;
+	stream_open(inode, file);
+
+	return 0;
+}
+
+static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,
+				   const struct input_absinfo *abs)
+{
+	int min, max, range;
+
+	min = abs->minimum;
+	max = abs->maximum;
+
+	if ((min != 0 || max != 0) && max < min) {
+		printk(KERN_DEBUG
+		       "%s: invalid abs[%02x] min:%d max:%d\n",
+		       UINPUT_NAME, code, min, max);
+		return -EINVAL;
+	}
+
+	if (!check_sub_overflow(max, min, &range) && abs->flat > range) {
+		printk(KERN_DEBUG
+		       "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n",
+		       UINPUT_NAME, code, abs->flat, min, max);
+		return -EINVAL;
+	}
+
+	/*
+	 * Limit number of contacts to a reasonable value (100). This
+	 * ensures that we need less than 2 pages for struct input_mt
+	 * (we are not using in-kernel slot assignment so not going to
+	 * allocate memory for the "red" table), and we should have no
+	 * trouble getting this much memory.
+	 */
+	if (code == ABS_MT_SLOT && max > 99) {
+		printk(KERN_DEBUG
+		       "%s: unreasonably large number of slots requested: %d\n",
+		       UINPUT_NAME, max);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int uinput_validate_absbits(struct input_dev *dev)
+{
+	unsigned int cnt;
+	int error;
+
+	if (!test_bit(EV_ABS, dev->evbit))
+		return 0;
+
+	/*
+	 * Check if absmin/absmax/absfuzz/absflat are sane.
+	 */
+
+	for_each_set_bit(cnt, dev->absbit, ABS_CNT) {
+		if (!dev->absinfo)
+			return -EINVAL;
+
+		error = uinput_validate_absinfo(dev, cnt, &dev->absinfo[cnt]);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+static int uinput_dev_setup(struct uinput_device *udev,
+			    struct uinput_setup __user *arg)
+{
+	struct uinput_setup setup;
+	struct input_dev *dev;
+
+	if (udev->state == UIST_CREATED)
+		return -EINVAL;
+
+	if (copy_from_user(&setup, arg, sizeof(setup)))
+		return -EFAULT;
+
+	if (!setup.name[0])
+		return -EINVAL;
+
+	dev = udev->dev;
+	dev->id = setup.id;
+	udev->ff_effects_max = setup.ff_effects_max;
+
+	kfree(dev->name);
+	dev->name = kstrndup(setup.name, UINPUT_MAX_NAME_SIZE, GFP_KERNEL);
+	if (!dev->name)
+		return -ENOMEM;
+
+	udev->state = UIST_SETUP_COMPLETE;
+	return 0;
+}
+
+static int uinput_abs_setup(struct uinput_device *udev,
+			    struct uinput_setup __user *arg, size_t size)
+{
+	struct uinput_abs_setup setup = {};
+	struct input_dev *dev;
+	int error;
+
+	if (size > sizeof(setup))
+		return -E2BIG;
+
+	if (udev->state == UIST_CREATED)
+		return -EINVAL;
+
+	if (copy_from_user(&setup, arg, size))
+		return -EFAULT;
+
+	if (setup.code > ABS_MAX)
+		return -ERANGE;
+
+	dev = udev->dev;
+
+	error = uinput_validate_absinfo(dev, setup.code, &setup.absinfo);
+	if (error)
+		return error;
+
+	input_alloc_absinfo(dev);
+	if (!dev->absinfo)
+		return -ENOMEM;
+
+	set_bit(setup.code, dev->absbit);
+	dev->absinfo[setup.code] = setup.absinfo;
+	return 0;
+}
+
+/* legacy setup via write() */
+static int uinput_setup_device_legacy(struct uinput_device *udev,
+				      const char __user *buffer, size_t count)
+{
+	struct uinput_user_dev	*user_dev;
+	struct input_dev	*dev;
+	int			i;
+	int			retval;
+
+	if (count != sizeof(struct uinput_user_dev))
+		return -EINVAL;
+
+	if (!udev->dev) {
+		udev->dev = input_allocate_device();
+		if (!udev->dev)
+			return -ENOMEM;
+	}
+
+	dev = udev->dev;
+
+	user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
+	if (IS_ERR(user_dev))
+		return PTR_ERR(user_dev);
+
+	udev->ff_effects_max = user_dev->ff_effects_max;
+
+	/* Ensure name is filled in */
+	if (!user_dev->name[0]) {
+		retval = -EINVAL;
+		goto exit;
+	}
+
+	kfree(dev->name);
+	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
+			     GFP_KERNEL);
+	if (!dev->name) {
+		retval = -ENOMEM;
+		goto exit;
+	}
+
+	dev->id.bustype	= user_dev->id.bustype;
+	dev->id.vendor	= user_dev->id.vendor;
+	dev->id.product	= user_dev->id.product;
+	dev->id.version	= user_dev->id.version;
+
+	for (i = 0; i < ABS_CNT; i++) {
+		input_abs_set_max(dev, i, user_dev->absmax[i]);
+		input_abs_set_min(dev, i, user_dev->absmin[i]);
+		input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
+		input_abs_set_flat(dev, i, user_dev->absflat[i]);
+	}
+
+	retval = uinput_validate_absbits(dev);
+	if (retval < 0)
+		goto exit;
+
+	udev->state = UIST_SETUP_COMPLETE;
+	retval = count;
+
+ exit:
+	kfree(user_dev);
+	return retval;
+}
+
+/*
+ * Returns true if the given timestamp is valid (i.e., if all the following
+ * conditions are satisfied), false otherwise.
+ * 1) given timestamp is positive
+ * 2) it's within the allowed offset before the current time
+ * 3) it's not in the future
+ */
+static bool is_valid_timestamp(const ktime_t timestamp)
+{
+	ktime_t zero_time;
+	ktime_t current_time;
+	ktime_t min_time;
+	ktime_t offset;
+
+	zero_time = ktime_set(0, 0);
+	if (ktime_compare(zero_time, timestamp) >= 0)
+		return false;
+
+	current_time = ktime_get();
+	offset = ktime_set(UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS, 0);
+	min_time = ktime_sub(current_time, offset);
+
+	if (ktime_after(min_time, timestamp) || ktime_after(timestamp, current_time))
+		return false;
+
+	return true;
+}
+
+static ssize_t uinput_inject_events(struct uinput_device *udev,
+				    const char __user *buffer, size_t count)
+{
+	struct input_event ev;
+	size_t bytes = 0;
+	ktime_t timestamp;
+
+	if (count != 0 && count < input_event_size())
+		return -EINVAL;
+
+	while (bytes + input_event_size() <= count) {
+		/*
+		 * Note that even if some events were fetched successfully
+		 * we are still going to return EFAULT instead of partial
+		 * count to let userspace know that it got it's buffers
+		 * all wrong.
+		 */
+		if (input_event_from_user(buffer + bytes, &ev))
+			return -EFAULT;
+
+		timestamp = ktime_set(ev.input_event_sec, ev.input_event_usec * NSEC_PER_USEC);
+		if (is_valid_timestamp(timestamp))
+			input_set_timestamp(udev->dev, timestamp);
+
+		input_event(udev->dev, ev.type, ev.code, ev.value);
+		bytes += input_event_size();
+		cond_resched();
+	}
+
+	return bytes;
+}
+
+static ssize_t uinput_write(struct file *file, const char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	struct uinput_device *udev = file->private_data;
+	int retval;
+
+	if (count == 0)
+		return 0;
+
+	retval = mutex_lock_interruptible(&udev->mutex);
+	if (retval)
+		return retval;
+
+	retval = udev->state == UIST_CREATED ?
+			uinput_inject_events(udev, buffer, count) :
+			uinput_setup_device_legacy(udev, buffer, count);
+
+	mutex_unlock(&udev->mutex);
+
+	return retval;
+}
+
+static bool uinput_fetch_next_event(struct uinput_device *udev,
+				    struct input_event *event)
+{
+	bool have_event;
+
+	spin_lock_irq(&udev->dev->event_lock);
+
+	have_event = udev->head != udev->tail;
+	if (have_event) {
+		*event = udev->buff[udev->tail];
+		udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
+	}
+
+	spin_unlock_irq(&udev->dev->event_lock);
+
+	return have_event;
+}
+
+static ssize_t uinput_events_to_user(struct uinput_device *udev,
+				     char __user *buffer, size_t count)
+{
+	struct input_event event;
+	size_t read = 0;
+
+	while (read + input_event_size() <= count &&
+	       uinput_fetch_next_event(udev, &event)) {
+
+		if (input_event_to_user(buffer + read, &event))
+			return -EFAULT;
+
+		read += input_event_size();
+	}
+
+	return read;
+}
+
+static ssize_t uinput_read(struct file *file, char __user *buffer,
+			   size_t count, loff_t *ppos)
+{
+	struct uinput_device *udev = file->private_data;
+	ssize_t retval;
+
+	if (count != 0 && count < input_event_size())
+		return -EINVAL;
+
+	do {
+		retval = mutex_lock_interruptible(&udev->mutex);
+		if (retval)
+			return retval;
+
+		if (udev->state != UIST_CREATED)
+			retval = -ENODEV;
+		else if (udev->head == udev->tail &&
+			 (file->f_flags & O_NONBLOCK))
+			retval = -EAGAIN;
+		else
+			retval = uinput_events_to_user(udev, buffer, count);
+
+		mutex_unlock(&udev->mutex);
+
+		if (retval || count == 0)
+			break;
+
+		if (!(file->f_flags & O_NONBLOCK))
+			retval = wait_event_interruptible(udev->waitq,
+						  udev->head != udev->tail ||
+						  udev->state != UIST_CREATED);
+	} while (retval == 0);
+
+	return retval;
+}
+
+static __poll_t uinput_poll(struct file *file, poll_table *wait)
+{
+	struct uinput_device *udev = file->private_data;
+	__poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uinput is always writable */
+
+	poll_wait(file, &udev->waitq, wait);
+
+	if (udev->head != udev->tail)
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	return mask;
+}
+
+static int uinput_release(struct inode *inode, struct file *file)
+{
+	struct uinput_device *udev = file->private_data;
+
+	uinput_destroy_device(udev);
+	kfree(udev);
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+struct uinput_ff_upload_compat {
+	__u32			request_id;
+	__s32			retval;
+	struct ff_effect_compat	effect;
+	struct ff_effect_compat	old;
+};
+
+static int uinput_ff_upload_to_user(char __user *buffer,
+				    const struct uinput_ff_upload *ff_up)
+{
+	if (in_compat_syscall()) {
+		struct uinput_ff_upload_compat ff_up_compat;
+
+		memset(&ff_up_compat, 0, sizeof(ff_up_compat));
+		ff_up_compat.request_id = ff_up->request_id;
+		ff_up_compat.retval = ff_up->retval;
+		/*
+		 * It so happens that the pointer that gives us the trouble
+		 * is the last field in the structure. Since we don't support
+		 * custom waveforms in uinput anyway we can just copy the whole
+		 * thing (to the compat size) and ignore the pointer.
+		 */
+		memcpy(&ff_up_compat.effect, &ff_up->effect,
+			sizeof(struct ff_effect_compat));
+		memcpy(&ff_up_compat.old, &ff_up->old,
+			sizeof(struct ff_effect_compat));
+
+		if (copy_to_user(buffer, &ff_up_compat,
+				 sizeof(struct uinput_ff_upload_compat)))
+			return -EFAULT;
+	} else {
+		if (copy_to_user(buffer, ff_up,
+				 sizeof(struct uinput_ff_upload)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int uinput_ff_upload_from_user(const char __user *buffer,
+				      struct uinput_ff_upload *ff_up)
+{
+	if (in_compat_syscall()) {
+		struct uinput_ff_upload_compat ff_up_compat;
+
+		if (copy_from_user(&ff_up_compat, buffer,
+				   sizeof(struct uinput_ff_upload_compat)))
+			return -EFAULT;
+
+		ff_up->request_id = ff_up_compat.request_id;
+		ff_up->retval = ff_up_compat.retval;
+		memcpy(&ff_up->effect, &ff_up_compat.effect,
+			sizeof(struct ff_effect_compat));
+		memcpy(&ff_up->old, &ff_up_compat.old,
+			sizeof(struct ff_effect_compat));
+
+	} else {
+		if (copy_from_user(ff_up, buffer,
+				   sizeof(struct uinput_ff_upload)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+#else
+
+static int uinput_ff_upload_to_user(char __user *buffer,
+				    const struct uinput_ff_upload *ff_up)
+{
+	if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int uinput_ff_upload_from_user(const char __user *buffer,
+				      struct uinput_ff_upload *ff_up)
+{
+	if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
+		return -EFAULT;
+
+	return 0;
+}
+
+#endif
+
+#define uinput_set_bit(_arg, _bit, _max)		\
+({							\
+	int __ret = 0;					\
+	if (udev->state == UIST_CREATED)		\
+		__ret =  -EINVAL;			\
+	else if ((_arg) > (_max))			\
+		__ret = -EINVAL;			\
+	else set_bit((_arg), udev->dev->_bit);		\
+	__ret;						\
+})
+
+static int uinput_str_to_user(void __user *dest, const char *str,
+			      unsigned int maxlen)
+{
+	char __user *p = dest;
+	int len, ret;
+
+	if (!str)
+		return -ENOENT;
+
+	if (maxlen == 0)
+		return -EINVAL;
+
+	len = strlen(str) + 1;
+	if (len > maxlen)
+		len = maxlen;
+
+	ret = copy_to_user(p, str, len);
+	if (ret)
+		return -EFAULT;
+
+	/* force terminating '\0' */
+	ret = put_user(0, p + len - 1);
+	return ret ? -EFAULT : len;
+}
+
+static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
+				 unsigned long arg, void __user *p)
+{
+	int			retval;
+	struct uinput_device	*udev = file->private_data;
+	struct uinput_ff_upload ff_up;
+	struct uinput_ff_erase  ff_erase;
+	struct uinput_request   *req;
+	char			*phys;
+	const char		*name;
+	unsigned int		size;
+
+	retval = mutex_lock_interruptible(&udev->mutex);
+	if (retval)
+		return retval;
+
+	if (!udev->dev) {
+		udev->dev = input_allocate_device();
+		if (!udev->dev) {
+			retval = -ENOMEM;
+			goto out;
+		}
+	}
+
+	switch (cmd) {
+	case UI_GET_VERSION:
+		if (put_user(UINPUT_VERSION, (unsigned int __user *)p))
+			retval = -EFAULT;
+		goto out;
+
+	case UI_DEV_CREATE:
+		retval = uinput_create_device(udev);
+		goto out;
+
+	case UI_DEV_DESTROY:
+		uinput_destroy_device(udev);
+		goto out;
+
+	case UI_DEV_SETUP:
+		retval = uinput_dev_setup(udev, p);
+		goto out;
+
+	/* UI_ABS_SETUP is handled in the variable size ioctls */
+
+	case UI_SET_EVBIT:
+		retval = uinput_set_bit(arg, evbit, EV_MAX);
+		goto out;
+
+	case UI_SET_KEYBIT:
+		retval = uinput_set_bit(arg, keybit, KEY_MAX);
+		goto out;
+
+	case UI_SET_RELBIT:
+		retval = uinput_set_bit(arg, relbit, REL_MAX);
+		goto out;
+
+	case UI_SET_ABSBIT:
+		retval = uinput_set_bit(arg, absbit, ABS_MAX);
+		goto out;
+
+	case UI_SET_MSCBIT:
+		retval = uinput_set_bit(arg, mscbit, MSC_MAX);
+		goto out;
+
+	case UI_SET_LEDBIT:
+		retval = uinput_set_bit(arg, ledbit, LED_MAX);
+		goto out;
+
+	case UI_SET_SNDBIT:
+		retval = uinput_set_bit(arg, sndbit, SND_MAX);
+		goto out;
+
+	case UI_SET_FFBIT:
+		retval = uinput_set_bit(arg, ffbit, FF_MAX);
+		goto out;
+
+	case UI_SET_SWBIT:
+		retval = uinput_set_bit(arg, swbit, SW_MAX);
+		goto out;
+
+	case UI_SET_PROPBIT:
+		retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
+		goto out;
+
+	case UI_SET_PHYS:
+		if (udev->state == UIST_CREATED) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		phys = strndup_user(p, 1024);
+		if (IS_ERR(phys)) {
+			retval = PTR_ERR(phys);
+			goto out;
+		}
+
+		kfree(udev->dev->phys);
+		udev->dev->phys = phys;
+		goto out;
+
+	case UI_BEGIN_FF_UPLOAD:
+		retval = uinput_ff_upload_from_user(p, &ff_up);
+		if (retval)
+			goto out;
+
+		req = uinput_request_find(udev, ff_up.request_id);
+		if (!req || req->code != UI_FF_UPLOAD ||
+		    !req->u.upload.effect) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		ff_up.retval = 0;
+		ff_up.effect = *req->u.upload.effect;
+		if (req->u.upload.old)
+			ff_up.old = *req->u.upload.old;
+		else
+			memset(&ff_up.old, 0, sizeof(struct ff_effect));
+
+		retval = uinput_ff_upload_to_user(p, &ff_up);
+		goto out;
+
+	case UI_BEGIN_FF_ERASE:
+		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
+			retval = -EFAULT;
+			goto out;
+		}
+
+		req = uinput_request_find(udev, ff_erase.request_id);
+		if (!req || req->code != UI_FF_ERASE) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		ff_erase.retval = 0;
+		ff_erase.effect_id = req->u.effect_id;
+		if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
+			retval = -EFAULT;
+			goto out;
+		}
+
+		goto out;
+
+	case UI_END_FF_UPLOAD:
+		retval = uinput_ff_upload_from_user(p, &ff_up);
+		if (retval)
+			goto out;
+
+		req = uinput_request_find(udev, ff_up.request_id);
+		if (!req || req->code != UI_FF_UPLOAD ||
+		    !req->u.upload.effect) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		req->retval = ff_up.retval;
+		complete(&req->done);
+		goto out;
+
+	case UI_END_FF_ERASE:
+		if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
+			retval = -EFAULT;
+			goto out;
+		}
+
+		req = uinput_request_find(udev, ff_erase.request_id);
+		if (!req || req->code != UI_FF_ERASE) {
+			retval = -EINVAL;
+			goto out;
+		}
+
+		req->retval = ff_erase.retval;
+		complete(&req->done);
+		goto out;
+	}
+
+	size = _IOC_SIZE(cmd);
+
+	/* Now check variable-length commands */
+	switch (cmd & ~IOCSIZE_MASK) {
+	case UI_GET_SYSNAME(0):
+		if (udev->state != UIST_CREATED) {
+			retval = -ENOENT;
+			goto out;
+		}
+		name = dev_name(&udev->dev->dev);
+		retval = uinput_str_to_user(p, name, size);
+		goto out;
+
+	case UI_ABS_SETUP & ~IOCSIZE_MASK:
+		retval = uinput_abs_setup(udev, p, size);
+		goto out;
+	}
+
+	retval = -EINVAL;
+ out:
+	mutex_unlock(&udev->mutex);
+	return retval;
+}
+
+static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
+}
+
+#ifdef CONFIG_COMPAT
+
+/*
+ * These IOCTLs change their size and thus their numbers between
+ * 32 and 64 bits.
+ */
+#define UI_SET_PHYS_COMPAT		\
+	_IOW(UINPUT_IOCTL_BASE, 108, compat_uptr_t)
+#define UI_BEGIN_FF_UPLOAD_COMPAT	\
+	_IOWR(UINPUT_IOCTL_BASE, 200, struct uinput_ff_upload_compat)
+#define UI_END_FF_UPLOAD_COMPAT		\
+	_IOW(UINPUT_IOCTL_BASE, 201, struct uinput_ff_upload_compat)
+
+static long uinput_compat_ioctl(struct file *file,
+				unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case UI_SET_PHYS_COMPAT:
+		cmd = UI_SET_PHYS;
+		break;
+	case UI_BEGIN_FF_UPLOAD_COMPAT:
+		cmd = UI_BEGIN_FF_UPLOAD;
+		break;
+	case UI_END_FF_UPLOAD_COMPAT:
+		cmd = UI_END_FF_UPLOAD;
+		break;
+	}
+
+	return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations uinput_fops = {
+	.owner		= THIS_MODULE,
+	.open		= uinput_open,
+	.release	= uinput_release,
+	.read		= uinput_read,
+	.write		= uinput_write,
+	.poll		= uinput_poll,
+	.unlocked_ioctl	= uinput_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= uinput_compat_ioctl,
+#endif
+};
+
+static struct miscdevice uinput_misc = {
+	.fops		= &uinput_fops,
+	.minor		= UINPUT_MINOR,
+	.name		= UINPUT_NAME,
+};
+module_misc_device(uinput_misc);
+
+MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
+MODULE_ALIAS("devname:" UINPUT_NAME);
+
+MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
+MODULE_DESCRIPTION("User level driver support for input subsystem");
+MODULE_LICENSE("GPL");