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, 148 insertions, 0 deletions

diff --git a/drivers/mfd/tps65086.c b/drivers/mfd/tps65086.c
new file mode 100644
index 000000000..54832e932
--- /dev/null
+++ b/drivers/mfd/tps65086.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 Texas Instruments Incorporated - https://www.ti.com/
+ *	Andrew F. Davis <afd@ti.com>
+ *
+ * Based on the TPS65912 driver
+ */
+
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+
+#include <linux/mfd/tps65086.h>
+
+static const struct mfd_cell tps65086_cells[] = {
+	{ .name = "tps65086-regulator", },
+	{ .name = "tps65086-gpio", },
+	{ .name = "tps65086-reset", },
+};
+
+static const struct regmap_range tps65086_yes_ranges[] = {
+	regmap_reg_range(TPS65086_IRQ, TPS65086_IRQ),
+	regmap_reg_range(TPS65086_PMICSTAT, TPS65086_SHUTDNSRC),
+	regmap_reg_range(TPS65086_GPOCTRL, TPS65086_GPOCTRL),
+	regmap_reg_range(TPS65086_PG_STATUS1, TPS65086_OC_STATUS),
+};
+
+static const struct regmap_access_table tps65086_volatile_table = {
+	.yes_ranges = tps65086_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(tps65086_yes_ranges),
+};
+
+static const struct regmap_config tps65086_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_MAPLE,
+	.volatile_table = &tps65086_volatile_table,
+	.max_register = TPS65086_OC_STATUS,
+};
+
+static const struct regmap_irq tps65086_irqs[] = {
+	REGMAP_IRQ_REG(TPS65086_IRQ_DIETEMP, 0, TPS65086_IRQ_DIETEMP_MASK),
+	REGMAP_IRQ_REG(TPS65086_IRQ_SHUTDN, 0, TPS65086_IRQ_SHUTDN_MASK),
+	REGMAP_IRQ_REG(TPS65086_IRQ_FAULT, 0, TPS65086_IRQ_FAULT_MASK),
+};
+
+static const struct regmap_irq_chip tps65086_irq_chip = {
+	.name = "tps65086",
+	.status_base = TPS65086_IRQ,
+	.mask_base = TPS65086_IRQ_MASK,
+	.ack_base = TPS65086_IRQ,
+	.init_ack_masked = true,
+	.num_regs = 1,
+	.irqs = tps65086_irqs,
+	.num_irqs = ARRAY_SIZE(tps65086_irqs),
+};
+
+static const struct of_device_id tps65086_of_match_table[] = {
+	{ .compatible = "ti,tps65086", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, tps65086_of_match_table);
+
+static int tps65086_probe(struct i2c_client *client)
+{
+	struct tps65086 *tps;
+	unsigned int version;
+	int ret;
+
+	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
+	if (!tps)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, tps);
+	tps->dev = &client->dev;
+	tps->irq = client->irq;
+
+	tps->regmap = devm_regmap_init_i2c(client, &tps65086_regmap_config);
+	if (IS_ERR(tps->regmap)) {
+		dev_err(tps->dev, "Failed to initialize register map\n");
+		return PTR_ERR(tps->regmap);
+	}
+
+	/* Store device ID to load regulator configuration that fit to IC variant */
+	ret = regmap_read(tps->regmap, TPS65086_DEVICEID1, &tps->chip_id);
+	if (ret) {
+		dev_err(tps->dev, "Failed to read revision register 1\n");
+		return ret;
+	}
+
+	ret = regmap_read(tps->regmap, TPS65086_DEVICEID2, &version);
+	if (ret) {
+		dev_err(tps->dev, "Failed to read revision register 2\n");
+		return ret;
+	}
+
+	dev_info(tps->dev, "Device: TPS65086%01lX, OTP: %c, Rev: %ld\n",
+		 (version & TPS65086_DEVICEID2_PART_MASK),
+		 (char)((version & TPS65086_DEVICEID2_OTP_MASK) >> 4) + 'A',
+		 (version & TPS65086_DEVICEID2_REV_MASK) >> 6);
+
+	if (tps->irq > 0) {
+		ret = regmap_add_irq_chip(tps->regmap, tps->irq, IRQF_ONESHOT, 0,
+					  &tps65086_irq_chip, &tps->irq_data);
+		if (ret) {
+			dev_err(tps->dev, "Failed to register IRQ chip\n");
+			return ret;
+		}
+	}
+
+	ret = mfd_add_devices(tps->dev, PLATFORM_DEVID_AUTO, tps65086_cells,
+			      ARRAY_SIZE(tps65086_cells), NULL, 0,
+			      regmap_irq_get_domain(tps->irq_data));
+	if (ret && tps->irq > 0)
+		regmap_del_irq_chip(tps->irq, tps->irq_data);
+
+	return ret;
+}
+
+static void tps65086_remove(struct i2c_client *client)
+{
+	struct tps65086 *tps = i2c_get_clientdata(client);
+
+	if (tps->irq > 0)
+		regmap_del_irq_chip(tps->irq, tps->irq_data);
+}
+
+static const struct i2c_device_id tps65086_id_table[] = {
+	{ "tps65086" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, tps65086_id_table);
+
+static struct i2c_driver tps65086_driver = {
+	.driver		= {
+		.name	= "tps65086",
+		.of_match_table = tps65086_of_match_table,
+	},
+	.probe		= tps65086_probe,
+	.remove		= tps65086_remove,
+	.id_table       = tps65086_id_table,
+};
+module_i2c_driver(tps65086_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("TPS65086 PMIC Driver");
+MODULE_LICENSE("GPL v2");