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, 180 insertions, 0 deletions

diff --git a/drivers/mfd/max77705.c b/drivers/mfd/max77705.c
new file mode 100644
index 000000000..e98c76d6b
--- /dev/null
+++ b/drivers/mfd/max77705.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Maxim MAX77705 PMIC core driver
+ *
+ * Copyright (C) 2025 Dzmitry Sankouski <dsankouski@gmail.com>
+ **/
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max77705-private.h>
+#include <linux/mfd/max77693-common.h>
+#include <linux/pm.h>
+#include <linux/power/max17042_battery.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+
+static struct mfd_cell max77705_devs[] = {
+	MFD_CELL_OF("max77705-rgb", NULL, NULL, 0, 0, "maxim,max77705-rgb"),
+	MFD_CELL_OF("max77705-charger", NULL, NULL, 0, 0, "maxim,max77705-charger"),
+	MFD_CELL_OF("max77705-haptic", NULL, NULL, 0, 0, "maxim,max77705-haptic"),
+};
+
+static const struct regmap_range max77705_readable_ranges[] = {
+	regmap_reg_range(MAX77705_PMIC_REG_PMICID1,		MAX77705_PMIC_REG_BSTOUT_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_INTSRC,		MAX77705_PMIC_REG_RESERVED_29),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_MCONFIG,		MAX77705_PMIC_REG_MCONFIG2),
+	regmap_reg_range(MAX77705_PMIC_REG_FORCE_EN_MASK,	MAX77705_PMIC_REG_FORCE_EN_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL2,	MAX77705_PMIC_REG_BOOSTCONTROL2),
+	regmap_reg_range(MAX77705_PMIC_REG_SW_RESET,		MAX77705_PMIC_REG_USBC_RESET),
+};
+
+static const struct regmap_range max77705_writable_ranges[] = {
+	regmap_reg_range(MAX77705_PMIC_REG_MAINCTRL1,		MAX77705_PMIC_REG_BSTOUT_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_INTSRC,		MAX77705_PMIC_REG_RESERVED_29),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_MCONFIG,		MAX77705_PMIC_REG_MCONFIG2),
+	regmap_reg_range(MAX77705_PMIC_REG_FORCE_EN_MASK,	MAX77705_PMIC_REG_FORCE_EN_MASK),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL1,	MAX77705_PMIC_REG_BOOSTCONTROL1),
+	regmap_reg_range(MAX77705_PMIC_REG_BOOSTCONTROL2,	MAX77705_PMIC_REG_BOOSTCONTROL2),
+	regmap_reg_range(MAX77705_PMIC_REG_SW_RESET,		MAX77705_PMIC_REG_USBC_RESET),
+};
+
+static const struct regmap_access_table max77705_readable_table = {
+	.yes_ranges = max77705_readable_ranges,
+	.n_yes_ranges = ARRAY_SIZE(max77705_readable_ranges),
+};
+
+static const struct regmap_access_table max77705_writable_table = {
+	.yes_ranges = max77705_writable_ranges,
+	.n_yes_ranges = ARRAY_SIZE(max77705_writable_ranges),
+};
+
+static const struct regmap_config max77705_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.rd_table = &max77705_readable_table,
+	.wr_table = &max77705_writable_table,
+	.max_register = MAX77705_PMIC_REG_USBC_RESET,
+};
+
+static const struct regmap_irq max77705_irqs[] = {
+	{ .mask = MAX77705_SRC_IRQ_CHG, },
+	{ .mask = MAX77705_SRC_IRQ_TOP, },
+	{ .mask = MAX77705_SRC_IRQ_FG, },
+	{ .mask = MAX77705_SRC_IRQ_USBC, },
+};
+
+static const struct regmap_irq_chip max77705_irq_chip = {
+	.name		= "max77705",
+	.status_base	= MAX77705_PMIC_REG_INTSRC,
+	.ack_base	= MAX77705_PMIC_REG_INTSRC,
+	.mask_base	= MAX77705_PMIC_REG_INTSRC_MASK,
+	.num_regs	= 1,
+	.irqs		= max77705_irqs,
+	.num_irqs	= ARRAY_SIZE(max77705_irqs),
+};
+
+static int max77705_i2c_probe(struct i2c_client *i2c)
+{
+	struct device *dev = &i2c->dev;
+	struct max77693_dev *max77705;
+	struct regmap_irq_chip_data *irq_data;
+	struct irq_domain *domain;
+	enum max77705_hw_rev pmic_rev;
+	unsigned int pmic_rev_value;
+	int ret;
+
+	max77705 = devm_kzalloc(dev, sizeof(*max77705), GFP_KERNEL);
+	if (!max77705)
+		return -ENOMEM;
+
+	max77705->i2c = i2c;
+	max77705->type = TYPE_MAX77705;
+	i2c_set_clientdata(i2c, max77705);
+
+	max77705->regmap = devm_regmap_init_i2c(i2c, &max77705_regmap_config);
+	if (IS_ERR(max77705->regmap))
+		return PTR_ERR(max77705->regmap);
+
+	ret = regmap_read(max77705->regmap, MAX77705_PMIC_REG_PMICREV, &pmic_rev_value);
+	if (ret < 0)
+		return -ENODEV;
+
+	pmic_rev = pmic_rev_value & MAX77705_REVISION_MASK;
+	if (pmic_rev != MAX77705_PASS3)
+		return dev_err_probe(dev, -ENODEV, "Rev.0x%x is not tested\n", pmic_rev);
+
+	/* Active Discharge Enable */
+	regmap_update_bits(max77705->regmap, MAX77705_PMIC_REG_MAINCTRL1, 1, 1);
+
+	ret = devm_regmap_add_irq_chip(dev, max77705->regmap,
+					i2c->irq,
+					IRQF_ONESHOT, 0,
+					&max77705_irq_chip,
+					&irq_data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add IRQ chip\n");
+
+	domain = regmap_irq_get_domain(irq_data);
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   max77705_devs, ARRAY_SIZE(max77705_devs),
+				   NULL, 0, domain);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register child devices\n");
+
+	ret = devm_device_init_wakeup(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to init wakeup\n");
+
+	return 0;
+}
+
+static int max77705_suspend(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	disable_irq(i2c->irq);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(i2c->irq);
+
+	return 0;
+}
+
+static int max77705_resume(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(i2c->irq);
+
+	enable_irq(i2c->irq);
+
+	return 0;
+}
+static DEFINE_SIMPLE_DEV_PM_OPS(max77705_pm_ops, max77705_suspend, max77705_resume);
+
+static const struct of_device_id max77705_i2c_of_match[] = {
+	{ .compatible = "maxim,max77705" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max77705_i2c_of_match);
+
+static struct i2c_driver max77705_i2c_driver = {
+	.driver = {
+		.name			= "max77705",
+		.of_match_table		= max77705_i2c_of_match,
+		.pm			= pm_sleep_ptr(&max77705_pm_ops),
+	},
+	.probe = max77705_i2c_probe
+};
+module_i2c_driver(max77705_i2c_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77705 PMIC core driver");
+MODULE_AUTHOR("Dzmitry Sankouski <dsankouski@gmail.com>");
+MODULE_LICENSE("GPL");