KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 466 insertions, 0 deletions

diff --git a/drivers/hid/hid-udraw-ps3.c b/drivers/hid/hid-udraw-ps3.c
new file mode 100644
index 000000000..b2e17ef2e
--- /dev/null
+++ b/drivers/hid/hid-udraw-ps3.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID driver for THQ PS3 uDraw tablet
+ *
+ * Copyright (C) 2016 Red Hat Inc. All Rights Reserved
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include "hid-ids.h"
+
+MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
+MODULE_DESCRIPTION("PS3 uDraw tablet driver");
+MODULE_LICENSE("GPL");
+
+/*
+ * Protocol information from:
+ * https://brandonw.net/udraw/
+ * and the source code of:
+ * https://vvvv.org/contribution/udraw-hid
+ */
+
+/*
+ * The device is setup with multiple input devices:
+ * - the touch area which works as a touchpad
+ * - the tablet area which works as a touchpad/drawing tablet
+ * - a joypad with a d-pad, and 7 buttons
+ * - an accelerometer device
+ */
+
+enum {
+	TOUCH_NONE,
+	TOUCH_PEN,
+	TOUCH_FINGER,
+	TOUCH_TWOFINGER
+};
+
+enum {
+	AXIS_X,
+	AXIS_Y,
+	AXIS_Z
+};
+
+/*
+ * Accelerometer min/max values
+ * in order, X, Y and Z
+ */
+static struct {
+	int min;
+	int max;
+} accel_limits[] = {
+	[AXIS_X] = { 490, 534 },
+	[AXIS_Y] = { 490, 534 },
+	[AXIS_Z] = { 492, 536 }
+};
+
+#define DEVICE_NAME "THQ uDraw Game Tablet for PS3"
+/* resolution in pixels */
+#define RES_X 1920
+#define RES_Y 1080
+/* size in mm */
+#define WIDTH  160
+#define HEIGHT 90
+#define PRESSURE_OFFSET 113
+#define MAX_PRESSURE (255 - PRESSURE_OFFSET)
+
+struct udraw {
+	struct input_dev *joy_input_dev;
+	struct input_dev *touch_input_dev;
+	struct input_dev *pen_input_dev;
+	struct input_dev *accel_input_dev;
+	struct hid_device *hdev;
+
+	/*
+	 * The device's two-finger support is pretty unreliable, as
+	 * the device could report a single touch when the two fingers
+	 * are too close together, and the distance between fingers, even
+	 * though reported is not in the same unit as the touches.
+	 *
+	 * We'll make do without it, and try to report the first touch
+	 * as reliably as possible.
+	 */
+	int last_one_finger_x;
+	int last_one_finger_y;
+	int last_two_finger_x;
+	int last_two_finger_y;
+};
+
+static int clamp_accel(int axis, int offset)
+{
+	axis = clamp(axis,
+			accel_limits[offset].min,
+			accel_limits[offset].max);
+	axis = (axis - accel_limits[offset].min) /
+			((accel_limits[offset].max -
+			  accel_limits[offset].min) * 0xFF);
+	return axis;
+}
+
+static int udraw_raw_event(struct hid_device *hdev, struct hid_report *report,
+	 u8 *data, int len)
+{
+	struct udraw *udraw = hid_get_drvdata(hdev);
+	int touch;
+	int x, y, z;
+
+	if (len != 27)
+		return 0;
+
+	if (data[11] == 0x00)
+		touch = TOUCH_NONE;
+	else if (data[11] == 0x40)
+		touch = TOUCH_PEN;
+	else if (data[11] == 0x80)
+		touch = TOUCH_FINGER;
+	else
+		touch = TOUCH_TWOFINGER;
+
+	/* joypad */
+	input_report_key(udraw->joy_input_dev, BTN_WEST, data[0] & 1);
+	input_report_key(udraw->joy_input_dev, BTN_SOUTH, !!(data[0] & 2));
+	input_report_key(udraw->joy_input_dev, BTN_EAST, !!(data[0] & 4));
+	input_report_key(udraw->joy_input_dev, BTN_NORTH, !!(data[0] & 8));
+
+	input_report_key(udraw->joy_input_dev, BTN_SELECT, !!(data[1] & 1));
+	input_report_key(udraw->joy_input_dev, BTN_START, !!(data[1] & 2));
+	input_report_key(udraw->joy_input_dev, BTN_MODE, !!(data[1] & 16));
+
+	x = y = 0;
+	switch (data[2]) {
+	case 0x0:
+		y = -127;
+		break;
+	case 0x1:
+		y = -127;
+		x = 127;
+		break;
+	case 0x2:
+		x = 127;
+		break;
+	case 0x3:
+		y = 127;
+		x = 127;
+		break;
+	case 0x4:
+		y = 127;
+		break;
+	case 0x5:
+		y = 127;
+		x = -127;
+		break;
+	case 0x6:
+		x = -127;
+		break;
+	case 0x7:
+		y = -127;
+		x = -127;
+		break;
+	default:
+		break;
+	}
+
+	input_report_abs(udraw->joy_input_dev, ABS_X, x);
+	input_report_abs(udraw->joy_input_dev, ABS_Y, y);
+
+	input_sync(udraw->joy_input_dev);
+
+	/* For pen and touchpad */
+	x = y = 0;
+	if (touch != TOUCH_NONE) {
+		if (data[15] != 0x0F)
+			x = data[15] * 256 + data[17];
+		if (data[16] != 0x0F)
+			y = data[16] * 256 + data[18];
+	}
+
+	if (touch == TOUCH_FINGER) {
+		/* Save the last one-finger touch */
+		udraw->last_one_finger_x = x;
+		udraw->last_one_finger_y = y;
+		udraw->last_two_finger_x = -1;
+		udraw->last_two_finger_y = -1;
+	} else if (touch == TOUCH_TWOFINGER) {
+		/*
+		 * We have a problem because x/y is the one for the
+		 * second finger but we want the first finger given
+		 * to user-space otherwise it'll look as if it jumped.
+		 *
+		 * See the udraw struct definition for why this was
+		 * implemented this way.
+		 */
+		if (udraw->last_two_finger_x == -1) {
+			/* Save the position of the 2nd finger */
+			udraw->last_two_finger_x = x;
+			udraw->last_two_finger_y = y;
+
+			x = udraw->last_one_finger_x;
+			y = udraw->last_one_finger_y;
+		} else {
+			/*
+			 * Offset the 2-finger coords using the
+			 * saved data from the first finger
+			 */
+			x = x - (udraw->last_two_finger_x
+				- udraw->last_one_finger_x);
+			y = y - (udraw->last_two_finger_y
+				- udraw->last_one_finger_y);
+		}
+	}
+
+	/* touchpad */
+	if (touch == TOUCH_FINGER || touch == TOUCH_TWOFINGER) {
+		input_report_key(udraw->touch_input_dev, BTN_TOUCH, 1);
+		input_report_key(udraw->touch_input_dev, BTN_TOOL_FINGER,
+				touch == TOUCH_FINGER);
+		input_report_key(udraw->touch_input_dev, BTN_TOOL_DOUBLETAP,
+				touch == TOUCH_TWOFINGER);
+
+		input_report_abs(udraw->touch_input_dev, ABS_X, x);
+		input_report_abs(udraw->touch_input_dev, ABS_Y, y);
+	} else {
+		input_report_key(udraw->touch_input_dev, BTN_TOUCH, 0);
+		input_report_key(udraw->touch_input_dev, BTN_TOOL_FINGER, 0);
+		input_report_key(udraw->touch_input_dev, BTN_TOOL_DOUBLETAP, 0);
+	}
+	input_sync(udraw->touch_input_dev);
+
+	/* pen */
+	if (touch == TOUCH_PEN) {
+		int level;
+
+		level = clamp(data[13] - PRESSURE_OFFSET,
+				0, MAX_PRESSURE);
+
+		input_report_key(udraw->pen_input_dev, BTN_TOUCH, (level != 0));
+		input_report_key(udraw->pen_input_dev, BTN_TOOL_PEN, 1);
+		input_report_abs(udraw->pen_input_dev, ABS_PRESSURE, level);
+		input_report_abs(udraw->pen_input_dev, ABS_X, x);
+		input_report_abs(udraw->pen_input_dev, ABS_Y, y);
+	} else {
+		input_report_key(udraw->pen_input_dev, BTN_TOUCH, 0);
+		input_report_key(udraw->pen_input_dev, BTN_TOOL_PEN, 0);
+		input_report_abs(udraw->pen_input_dev, ABS_PRESSURE, 0);
+	}
+	input_sync(udraw->pen_input_dev);
+
+	/* accel */
+	x = (data[19] + (data[20] << 8));
+	x = clamp_accel(x, AXIS_X);
+	y = (data[21] + (data[22] << 8));
+	y = clamp_accel(y, AXIS_Y);
+	z = (data[23] + (data[24] << 8));
+	z = clamp_accel(z, AXIS_Z);
+	input_report_abs(udraw->accel_input_dev, ABS_X, x);
+	input_report_abs(udraw->accel_input_dev, ABS_Y, y);
+	input_report_abs(udraw->accel_input_dev, ABS_Z, z);
+	input_sync(udraw->accel_input_dev);
+
+	/* let hidraw and hiddev handle the report */
+	return 0;
+}
+
+static int udraw_open(struct input_dev *dev)
+{
+	struct udraw *udraw = input_get_drvdata(dev);
+
+	return hid_hw_open(udraw->hdev);
+}
+
+static void udraw_close(struct input_dev *dev)
+{
+	struct udraw *udraw = input_get_drvdata(dev);
+
+	hid_hw_close(udraw->hdev);
+}
+
+static struct input_dev *allocate_and_setup(struct hid_device *hdev,
+		const char *name)
+{
+	struct input_dev *input_dev;
+
+	input_dev = devm_input_allocate_device(&hdev->dev);
+	if (!input_dev)
+		return NULL;
+
+	input_dev->name = name;
+	input_dev->phys = hdev->phys;
+	input_dev->dev.parent = &hdev->dev;
+	input_dev->open = udraw_open;
+	input_dev->close = udraw_close;
+	input_dev->uniq = hdev->uniq;
+	input_dev->id.bustype = hdev->bus;
+	input_dev->id.vendor  = hdev->vendor;
+	input_dev->id.product = hdev->product;
+	input_dev->id.version = hdev->version;
+	input_set_drvdata(input_dev, hid_get_drvdata(hdev));
+
+	return input_dev;
+}
+
+static bool udraw_setup_touch(struct udraw *udraw,
+		struct hid_device *hdev)
+{
+	struct input_dev *input_dev;
+
+	input_dev = allocate_and_setup(hdev, DEVICE_NAME " Touchpad");
+	if (!input_dev)
+		return false;
+
+	input_dev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
+
+	input_set_abs_params(input_dev, ABS_X, 0, RES_X, 1, 0);
+	input_abs_set_res(input_dev, ABS_X, RES_X / WIDTH);
+	input_set_abs_params(input_dev, ABS_Y, 0, RES_Y, 1, 0);
+	input_abs_set_res(input_dev, ABS_Y, RES_Y / HEIGHT);
+
+	set_bit(BTN_TOUCH, input_dev->keybit);
+	set_bit(BTN_TOOL_FINGER, input_dev->keybit);
+	set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
+
+	set_bit(INPUT_PROP_POINTER, input_dev->propbit);
+
+	udraw->touch_input_dev = input_dev;
+
+	return true;
+}
+
+static bool udraw_setup_pen(struct udraw *udraw,
+		struct hid_device *hdev)
+{
+	struct input_dev *input_dev;
+
+	input_dev = allocate_and_setup(hdev, DEVICE_NAME " Pen");
+	if (!input_dev)
+		return false;
+
+	input_dev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
+
+	input_set_abs_params(input_dev, ABS_X, 0, RES_X, 1, 0);
+	input_abs_set_res(input_dev, ABS_X, RES_X / WIDTH);
+	input_set_abs_params(input_dev, ABS_Y, 0, RES_Y, 1, 0);
+	input_abs_set_res(input_dev, ABS_Y, RES_Y / HEIGHT);
+	input_set_abs_params(input_dev, ABS_PRESSURE,
+			0, MAX_PRESSURE, 0, 0);
+
+	set_bit(BTN_TOUCH, input_dev->keybit);
+	set_bit(BTN_TOOL_PEN, input_dev->keybit);
+
+	set_bit(INPUT_PROP_POINTER, input_dev->propbit);
+
+	udraw->pen_input_dev = input_dev;
+
+	return true;
+}
+
+static bool udraw_setup_accel(struct udraw *udraw,
+		struct hid_device *hdev)
+{
+	struct input_dev *input_dev;
+
+	input_dev = allocate_and_setup(hdev, DEVICE_NAME " Accelerometer");
+	if (!input_dev)
+		return false;
+
+	input_dev->evbit[0] = BIT(EV_ABS);
+
+	/* 1G accel is reported as ~256, so clamp to 2G */
+	input_set_abs_params(input_dev, ABS_X, -512, 512, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, -512, 512, 0, 0);
+	input_set_abs_params(input_dev, ABS_Z, -512, 512, 0, 0);
+
+	set_bit(INPUT_PROP_ACCELEROMETER, input_dev->propbit);
+
+	udraw->accel_input_dev = input_dev;
+
+	return true;
+}
+
+static bool udraw_setup_joypad(struct udraw *udraw,
+		struct hid_device *hdev)
+{
+	struct input_dev *input_dev;
+
+	input_dev = allocate_and_setup(hdev, DEVICE_NAME " Joypad");
+	if (!input_dev)
+		return false;
+
+	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
+
+	set_bit(BTN_SOUTH, input_dev->keybit);
+	set_bit(BTN_NORTH, input_dev->keybit);
+	set_bit(BTN_EAST, input_dev->keybit);
+	set_bit(BTN_WEST, input_dev->keybit);
+	set_bit(BTN_SELECT, input_dev->keybit);
+	set_bit(BTN_START, input_dev->keybit);
+	set_bit(BTN_MODE, input_dev->keybit);
+
+	input_set_abs_params(input_dev, ABS_X, -127, 127, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, -127, 127, 0, 0);
+
+	udraw->joy_input_dev = input_dev;
+
+	return true;
+}
+
+static int udraw_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct udraw *udraw;
+	int ret;
+
+	udraw = devm_kzalloc(&hdev->dev, sizeof(struct udraw), GFP_KERNEL);
+	if (!udraw)
+		return -ENOMEM;
+
+	udraw->hdev = hdev;
+	udraw->last_two_finger_x = -1;
+	udraw->last_two_finger_y = -1;
+
+	hid_set_drvdata(hdev, udraw);
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		return ret;
+	}
+
+	if (!udraw_setup_joypad(udraw, hdev) ||
+	    !udraw_setup_touch(udraw, hdev) ||
+	    !udraw_setup_pen(udraw, hdev) ||
+	    !udraw_setup_accel(udraw, hdev)) {
+		hid_err(hdev, "could not allocate interfaces\n");
+		return -ENOMEM;
+	}
+
+	ret = input_register_device(udraw->joy_input_dev) ||
+		input_register_device(udraw->touch_input_dev) ||
+		input_register_device(udraw->pen_input_dev) ||
+		input_register_device(udraw->accel_input_dev);
+	if (ret) {
+		hid_err(hdev, "failed to register interfaces\n");
+		return ret;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW | HID_CONNECT_DRIVER);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id udraw_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_THQ, USB_DEVICE_ID_THQ_PS3_UDRAW) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, udraw_devices);
+
+static struct hid_driver udraw_driver = {
+	.name = "hid-udraw",
+	.id_table = udraw_devices,
+	.raw_event = udraw_raw_event,
+	.probe = udraw_probe,
+};
+module_hid_driver(udraw_driver);