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, 504 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/msg2638.c b/drivers/input/touchscreen/msg2638.c
new file mode 100644
index 000000000..cd40c284d
--- /dev/null
+++ b/drivers/input/touchscreen/msg2638.c
@@ -0,0 +1,504 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for MStar msg2638 touchscreens
+ *
+ * Copyright (c) 2021 Vincent Knecht <vincent.knecht@mailoo.org>
+ *
+ * Checksum and IRQ handler based on mstar_drv_common.c and
+ * mstar_drv_mutual_fw_control.c
+ * Copyright (c) 2006-2012 MStar Semiconductor, Inc.
+ *
+ * Driver structure based on zinitix.c by Michael Srba <Michael.Srba@seznam.cz>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#define MODE_DATA_RAW			0x5A
+
+#define MSG2138_MAX_FINGERS		2
+#define MSG2638_MAX_FINGERS		5
+
+#define MAX_BUTTONS			4
+
+#define CHIP_ON_DELAY_MS		15
+#define FIRMWARE_ON_DELAY_MS		50
+#define RESET_DELAY_MIN_US		10000
+#define RESET_DELAY_MAX_US		11000
+
+struct msg_chip_data {
+	irq_handler_t irq_handler;
+	unsigned int max_fingers;
+};
+
+struct msg2138_packet {
+	u8	xy_hi; /* higher bits of x and y coordinates */
+	u8	x_low;
+	u8	y_low;
+};
+
+struct msg2138_touch_event {
+	u8	magic;
+	struct	msg2138_packet pkt[MSG2138_MAX_FINGERS];
+	u8	checksum;
+};
+
+struct msg2638_packet {
+	u8	xy_hi; /* higher bits of x and y coordinates */
+	u8	x_low;
+	u8	y_low;
+	u8	pressure;
+};
+
+struct msg2638_touch_event {
+	u8	mode;
+	struct	msg2638_packet pkt[MSG2638_MAX_FINGERS];
+	u8	proximity;
+	u8	checksum;
+};
+
+struct msg2638_ts_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct touchscreen_properties prop;
+	struct regulator_bulk_data supplies[2];
+	struct gpio_desc *reset_gpiod;
+	int max_fingers;
+	u32 keycodes[MAX_BUTTONS];
+	int num_keycodes;
+};
+
+static u8 msg2638_checksum(u8 *data, u32 length)
+{
+	s32 sum = 0;
+	u32 i;
+
+	for (i = 0; i < length; i++)
+		sum += data[i];
+
+	return (u8)((-sum) & 0xFF);
+}
+
+static void msg2138_report_keys(struct msg2638_ts_data *msg2638, u8 keys)
+{
+	int i;
+
+	/* keys can be 0x00 or 0xff when all keys have been released */
+	if (keys == 0xff)
+		keys = 0;
+
+	for (i = 0; i < msg2638->num_keycodes; ++i)
+		input_report_key(msg2638->input_dev, msg2638->keycodes[i],
+				 keys & BIT(i));
+}
+
+static irqreturn_t msg2138_ts_irq_handler(int irq, void *msg2638_handler)
+{
+	struct msg2638_ts_data *msg2638 = msg2638_handler;
+	struct i2c_client *client = msg2638->client;
+	struct input_dev *input = msg2638->input_dev;
+	struct msg2138_touch_event touch_event;
+	u32 len = sizeof(touch_event);
+	struct i2c_msg msg[] = {
+		{
+			.addr	= client->addr,
+			.flags	= I2C_M_RD,
+			.len	= sizeof(touch_event),
+			.buf	= (u8 *)&touch_event,
+		},
+	};
+	struct msg2138_packet *p0, *p1;
+	u16 x, y, delta_x, delta_y;
+	int ret;
+
+	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+	if (ret != ARRAY_SIZE(msg)) {
+		dev_err(&client->dev,
+			"Failed I2C transfer in irq handler: %d\n",
+			ret < 0 ? ret : -EIO);
+		goto out;
+	}
+
+	if (msg2638_checksum((u8 *)&touch_event, len - 1) !=
+						touch_event.checksum) {
+		dev_err(&client->dev, "Failed checksum!\n");
+		goto out;
+	}
+
+	p0 = &touch_event.pkt[0];
+	p1 = &touch_event.pkt[1];
+
+	/* Ignore non-pressed finger data, but check for key code */
+	if (p0->xy_hi == 0xFF && p0->x_low == 0xFF && p0->y_low == 0xFF) {
+		if (p1->xy_hi == 0xFF && p1->y_low == 0xFF)
+			msg2138_report_keys(msg2638, p1->x_low);
+		goto report;
+	}
+
+	x = ((p0->xy_hi & 0xF0) << 4) | p0->x_low;
+	y = ((p0->xy_hi & 0x0F) << 8) | p0->y_low;
+
+	input_mt_slot(input, 0);
+	input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+	touchscreen_report_pos(input, &msg2638->prop, x, y, true);
+
+	/* Ignore non-pressed finger data */
+	if (p1->xy_hi == 0xFF && p1->x_low == 0xFF && p1->y_low == 0xFF)
+		goto report;
+
+	/* Second finger is reported as a delta position */
+	delta_x = ((p1->xy_hi & 0xF0) << 4) | p1->x_low;
+	delta_y = ((p1->xy_hi & 0x0F) << 8) | p1->y_low;
+
+	/* Ignore second finger if both deltas equal 0 */
+	if (delta_x == 0 && delta_y == 0)
+		goto report;
+
+	x += delta_x;
+	y += delta_y;
+
+	input_mt_slot(input, 1);
+	input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+	touchscreen_report_pos(input, &msg2638->prop, x, y, true);
+
+report:
+	input_mt_sync_frame(msg2638->input_dev);
+	input_sync(msg2638->input_dev);
+
+out:
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t msg2638_ts_irq_handler(int irq, void *msg2638_handler)
+{
+	struct msg2638_ts_data *msg2638 = msg2638_handler;
+	struct i2c_client *client = msg2638->client;
+	struct input_dev *input = msg2638->input_dev;
+	struct msg2638_touch_event touch_event;
+	u32 len = sizeof(touch_event);
+	struct i2c_msg msg[] = {
+		{
+			.addr	= client->addr,
+			.flags	= I2C_M_RD,
+			.len	= sizeof(touch_event),
+			.buf	= (u8 *)&touch_event,
+		},
+	};
+	struct msg2638_packet *p;
+	u16 x, y;
+	int ret;
+	int i;
+
+	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+	if (ret != ARRAY_SIZE(msg)) {
+		dev_err(&client->dev,
+			"Failed I2C transfer in irq handler: %d\n",
+			ret < 0 ? ret : -EIO);
+		goto out;
+	}
+
+	if (touch_event.mode != MODE_DATA_RAW)
+		goto out;
+
+	if (msg2638_checksum((u8 *)&touch_event, len - 1) !=
+						touch_event.checksum) {
+		dev_err(&client->dev, "Failed checksum!\n");
+		goto out;
+	}
+
+	for (i = 0; i < msg2638->max_fingers; i++) {
+		p = &touch_event.pkt[i];
+
+		/* Ignore non-pressed finger data */
+		if (p->xy_hi == 0xFF && p->x_low == 0xFF && p->y_low == 0xFF)
+			continue;
+
+		x = (((p->xy_hi & 0xF0) << 4) | p->x_low);
+		y = (((p->xy_hi & 0x0F) << 8) | p->y_low);
+
+		input_mt_slot(input, i);
+		input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+		touchscreen_report_pos(input, &msg2638->prop, x, y, true);
+	}
+
+	input_mt_sync_frame(msg2638->input_dev);
+	input_sync(msg2638->input_dev);
+
+out:
+	return IRQ_HANDLED;
+}
+
+static void msg2638_reset(struct msg2638_ts_data *msg2638)
+{
+	gpiod_set_value_cansleep(msg2638->reset_gpiod, 1);
+	usleep_range(RESET_DELAY_MIN_US, RESET_DELAY_MAX_US);
+	gpiod_set_value_cansleep(msg2638->reset_gpiod, 0);
+	msleep(FIRMWARE_ON_DELAY_MS);
+}
+
+static int msg2638_start(struct msg2638_ts_data *msg2638)
+{
+	int error;
+
+	error = regulator_bulk_enable(ARRAY_SIZE(msg2638->supplies),
+				      msg2638->supplies);
+	if (error) {
+		dev_err(&msg2638->client->dev,
+			"Failed to enable regulators: %d\n", error);
+		return error;
+	}
+
+	msleep(CHIP_ON_DELAY_MS);
+
+	msg2638_reset(msg2638);
+
+	enable_irq(msg2638->client->irq);
+
+	return 0;
+}
+
+static int msg2638_stop(struct msg2638_ts_data *msg2638)
+{
+	int error;
+
+	disable_irq(msg2638->client->irq);
+
+	error = regulator_bulk_disable(ARRAY_SIZE(msg2638->supplies),
+				       msg2638->supplies);
+	if (error) {
+		dev_err(&msg2638->client->dev,
+			"Failed to disable regulators: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int msg2638_input_open(struct input_dev *dev)
+{
+	struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
+
+	return msg2638_start(msg2638);
+}
+
+static void msg2638_input_close(struct input_dev *dev)
+{
+	struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
+
+	msg2638_stop(msg2638);
+}
+
+static int msg2638_init_input_dev(struct msg2638_ts_data *msg2638)
+{
+	struct device *dev = &msg2638->client->dev;
+	struct input_dev *input_dev;
+	int error;
+	int i;
+
+	input_dev = devm_input_allocate_device(dev);
+	if (!input_dev) {
+		dev_err(dev, "Failed to allocate input device.\n");
+		return -ENOMEM;
+	}
+
+	input_set_drvdata(input_dev, msg2638);
+	msg2638->input_dev = input_dev;
+
+	input_dev->name = "MStar TouchScreen";
+	input_dev->phys = "input/ts";
+	input_dev->id.bustype = BUS_I2C;
+	input_dev->open = msg2638_input_open;
+	input_dev->close = msg2638_input_close;
+
+	if (msg2638->num_keycodes) {
+		input_dev->keycode = msg2638->keycodes;
+		input_dev->keycodemax = msg2638->num_keycodes;
+		input_dev->keycodesize = sizeof(msg2638->keycodes[0]);
+		for (i = 0; i < msg2638->num_keycodes; i++)
+			input_set_capability(input_dev,
+					     EV_KEY, msg2638->keycodes[i]);
+	}
+
+	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
+	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
+
+	touchscreen_parse_properties(input_dev, true, &msg2638->prop);
+	if (!msg2638->prop.max_x || !msg2638->prop.max_y) {
+		dev_err(dev, "touchscreen-size-x and/or touchscreen-size-y not set in properties\n");
+		return -EINVAL;
+	}
+
+	error = input_mt_init_slots(input_dev, msg2638->max_fingers,
+				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+	if (error) {
+		dev_err(dev, "Failed to initialize MT slots: %d\n", error);
+		return error;
+	}
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(dev, "Failed to register input device: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int msg2638_ts_probe(struct i2c_client *client)
+{
+	const struct msg_chip_data *chip_data;
+	struct device *dev = &client->dev;
+	struct msg2638_ts_data *msg2638;
+	int error;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(dev, "Failed to assert adapter's support for plain I2C.\n");
+		return -ENXIO;
+	}
+
+	msg2638 = devm_kzalloc(dev, sizeof(*msg2638), GFP_KERNEL);
+	if (!msg2638)
+		return -ENOMEM;
+
+	msg2638->client = client;
+	i2c_set_clientdata(client, msg2638);
+
+	chip_data = device_get_match_data(&client->dev);
+	if (!chip_data || !chip_data->max_fingers) {
+		dev_err(dev, "Invalid or missing chip data\n");
+		return -EINVAL;
+	}
+
+	msg2638->max_fingers = chip_data->max_fingers;
+
+	msg2638->supplies[0].supply = "vdd";
+	msg2638->supplies[1].supply = "vddio";
+	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(msg2638->supplies),
+					msg2638->supplies);
+	if (error) {
+		dev_err(dev, "Failed to get regulators: %d\n", error);
+		return error;
+	}
+
+	msg2638->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(msg2638->reset_gpiod)) {
+		error = PTR_ERR(msg2638->reset_gpiod);
+		dev_err(dev, "Failed to request reset GPIO: %d\n", error);
+		return error;
+	}
+
+	msg2638->num_keycodes = device_property_count_u32(dev,
+							  "linux,keycodes");
+	if (msg2638->num_keycodes == -EINVAL) {
+		msg2638->num_keycodes = 0;
+	} else if (msg2638->num_keycodes < 0) {
+		dev_err(dev, "Unable to parse linux,keycodes property: %d\n",
+			msg2638->num_keycodes);
+		return msg2638->num_keycodes;
+	} else if (msg2638->num_keycodes > ARRAY_SIZE(msg2638->keycodes)) {
+		dev_warn(dev, "Found %d linux,keycodes but max is %zd, ignoring the rest\n",
+			 msg2638->num_keycodes, ARRAY_SIZE(msg2638->keycodes));
+		msg2638->num_keycodes = ARRAY_SIZE(msg2638->keycodes);
+	}
+
+	if (msg2638->num_keycodes > 0) {
+		error = device_property_read_u32_array(dev, "linux,keycodes",
+						       msg2638->keycodes,
+						       msg2638->num_keycodes);
+		if (error) {
+			dev_err(dev, "Unable to read linux,keycodes values: %d\n",
+				error);
+			return error;
+		}
+	}
+
+	error = devm_request_threaded_irq(dev, client->irq,
+					  NULL, chip_data->irq_handler,
+					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
+					  client->name, msg2638);
+	if (error) {
+		dev_err(dev, "Failed to request IRQ: %d\n", error);
+		return error;
+	}
+
+	error = msg2638_init_input_dev(msg2638);
+	if (error) {
+		dev_err(dev, "Failed to initialize input device: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int msg2638_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
+
+	guard(mutex)(&msg2638->input_dev->mutex);
+
+	if (input_device_enabled(msg2638->input_dev))
+		msg2638_stop(msg2638);
+
+	return 0;
+}
+
+static int msg2638_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
+	int error;
+
+	guard(mutex)(&msg2638->input_dev->mutex);
+
+	if (input_device_enabled(msg2638->input_dev)) {
+		error = msg2638_start(msg2638);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(msg2638_pm_ops, msg2638_suspend, msg2638_resume);
+
+static const struct msg_chip_data msg2138_data = {
+	.irq_handler = msg2138_ts_irq_handler,
+	.max_fingers = MSG2138_MAX_FINGERS,
+};
+
+static const struct msg_chip_data msg2638_data = {
+	.irq_handler = msg2638_ts_irq_handler,
+	.max_fingers = MSG2638_MAX_FINGERS,
+};
+
+static const struct of_device_id msg2638_of_match[] = {
+	{ .compatible = "mstar,msg2138", .data = &msg2138_data },
+	{ .compatible = "mstar,msg2638", .data = &msg2638_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, msg2638_of_match);
+
+static struct i2c_driver msg2638_ts_driver = {
+	.probe = msg2638_ts_probe,
+	.driver = {
+		.name = "MStar-TS",
+		.pm = pm_sleep_ptr(&msg2638_pm_ops),
+		.of_match_table = msg2638_of_match,
+	},
+};
+module_i2c_driver(msg2638_ts_driver);
+
+MODULE_AUTHOR("Vincent Knecht <vincent.knecht@mailoo.org>");
+MODULE_DESCRIPTION("MStar MSG2638 touchscreen driver");
+MODULE_LICENSE("GPL v2");