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, 159 insertions, 0 deletions

diff --git a/drivers/mfd/88pm80x.c b/drivers/mfd/88pm80x.c
new file mode 100644
index 000000000..bbc1a87f0
--- /dev/null
+++ b/drivers/mfd/88pm80x.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * I2C driver for Marvell 88PM80x
+ *
+ * Copyright (C) 2012 Marvell International Ltd.
+ * Haojian Zhuang <haojian.zhuang@marvell.com>
+ * Joseph(Yossi) Hanin <yhanin@marvell.com>
+ * Qiao Zhou <zhouqiao@marvell.com>
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/mfd/88pm80x.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/err.h>
+
+/* 88pm80x chips have same definition for chip id register. */
+#define PM80X_CHIP_ID			(0x00)
+#define PM80X_CHIP_ID_NUM(x)		(((x) >> 5) & 0x7)
+#define PM80X_CHIP_ID_REVISION(x)	((x) & 0x1F)
+
+struct pm80x_chip_mapping {
+	unsigned int	id;
+	int		type;
+};
+
+static struct pm80x_chip_mapping chip_mapping[] = {
+	/* 88PM800 chip id number */
+	{0x3,	CHIP_PM800},
+	/* 88PM805 chip id number */
+	{0x0,	CHIP_PM805},
+	/* 88PM860 chip id number */
+	{0x4,	CHIP_PM860},
+};
+
+/*
+ * workaround: some registers needed by pm805 are defined in pm800, so
+ * need to use this global variable to maintain the relation between
+ * pm800 and pm805. would remove it after HW chip fixes the issue.
+ */
+static struct pm80x_chip *g_pm80x_chip;
+
+const struct regmap_config pm80x_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+EXPORT_SYMBOL_GPL(pm80x_regmap_config);
+
+
+int pm80x_init(struct i2c_client *client)
+{
+	struct pm80x_chip *chip;
+	struct regmap *map;
+	unsigned int val;
+	int i, ret = 0;
+
+	chip =
+	    devm_kzalloc(&client->dev, sizeof(struct pm80x_chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	map = devm_regmap_init_i2c(client, &pm80x_regmap_config);
+	if (IS_ERR(map)) {
+		ret = PTR_ERR(map);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	chip->client = client;
+	chip->regmap = map;
+
+	chip->irq = client->irq;
+
+	chip->dev = &client->dev;
+	i2c_set_clientdata(chip->client, chip);
+
+	ret = regmap_read(chip->regmap, PM80X_CHIP_ID, &val);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to read CHIP ID: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(chip_mapping); i++) {
+		if (chip_mapping[i].id == PM80X_CHIP_ID_NUM(val)) {
+			chip->type = chip_mapping[i].type;
+			break;
+		}
+	}
+
+	if (i == ARRAY_SIZE(chip_mapping)) {
+		dev_err(chip->dev,
+			"Failed to detect Marvell 88PM800:ChipID[0x%x]\n", val);
+		return -EINVAL;
+	}
+
+	device_init_wakeup(&client->dev, 1);
+
+	/*
+	 * workaround: set g_pm80x_chip to the first probed chip. if the
+	 * second chip is probed, just point to the companion to each
+	 * other so that pm805 can access those specific register. would
+	 * remove it after HW chip fixes the issue.
+	 */
+	if (!g_pm80x_chip)
+		g_pm80x_chip = chip;
+	else {
+		chip->companion = g_pm80x_chip->client;
+		g_pm80x_chip->companion = chip->client;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm80x_init);
+
+int pm80x_deinit(void)
+{
+	/*
+	 * workaround: clear the dependency between pm800 and pm805.
+	 * would remove it after HW chip fixes the issue.
+	 */
+	if (g_pm80x_chip->companion)
+		g_pm80x_chip->companion = NULL;
+	else
+		g_pm80x_chip = NULL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm80x_deinit);
+
+static int pm80x_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pm80x_chip *chip = i2c_get_clientdata(client);
+
+	if (chip && chip->wu_flag)
+		if (device_may_wakeup(chip->dev))
+			enable_irq_wake(chip->irq);
+
+	return 0;
+}
+
+static int pm80x_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pm80x_chip *chip = i2c_get_clientdata(client);
+
+	if (chip && chip->wu_flag)
+		if (device_may_wakeup(chip->dev))
+			disable_irq_wake(chip->irq);
+
+	return 0;
+}
+
+EXPORT_GPL_SIMPLE_DEV_PM_OPS(pm80x_pm_ops, pm80x_suspend, pm80x_resume);
+
+MODULE_DESCRIPTION("I2C Driver for Marvell 88PM80x");
+MODULE_AUTHOR("Qiao Zhou <zhouqiao@marvell.com>");
+MODULE_LICENSE("GPL");