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, 246 insertions, 0 deletions

diff --git a/drivers/mfd/lp8788.c b/drivers/mfd/lp8788.c
new file mode 100644
index 000000000..32f255378
--- /dev/null
+++ b/drivers/mfd/lp8788.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * TI LP8788 MFD - core interface
+ *
+ * Copyright 2012 Texas Instruments
+ *
+ * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/lp8788.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define MAX_LP8788_REGISTERS		0xA2
+
+#define MFD_DEV_SIMPLE(_name)					\
+{								\
+	.name = LP8788_DEV_##_name,				\
+}
+
+#define MFD_DEV_WITH_ID(_name, _id)				\
+{								\
+	.name = LP8788_DEV_##_name,				\
+	.id = _id,						\
+}
+
+#define MFD_DEV_WITH_RESOURCE(_name, _resource, num_resource)	\
+{								\
+	.name = LP8788_DEV_##_name,				\
+	.resources = _resource,					\
+	.num_resources = num_resource,				\
+}
+
+static const struct resource chg_irqs[] = {
+	/* Charger Interrupts */
+	{
+		.start = LP8788_INT_CHG_INPUT_STATE,
+		.end   = LP8788_INT_PRECHG_TIMEOUT,
+		.name  = LP8788_CHG_IRQ,
+		.flags = IORESOURCE_IRQ,
+	},
+	/* Power Routing Switch Interrupts */
+	{
+		.start = LP8788_INT_ENTER_SYS_SUPPORT,
+		.end   = LP8788_INT_EXIT_SYS_SUPPORT,
+		.name  = LP8788_PRSW_IRQ,
+		.flags = IORESOURCE_IRQ,
+	},
+	/* Battery Interrupts */
+	{
+		.start = LP8788_INT_BATT_LOW,
+		.end   = LP8788_INT_NO_BATT,
+		.name  = LP8788_BATT_IRQ,
+		.flags = IORESOURCE_IRQ,
+	},
+};
+
+static const struct resource rtc_irqs[] = {
+	{
+		.start = LP8788_INT_RTC_ALARM1,
+		.end   = LP8788_INT_RTC_ALARM2,
+		.name  = LP8788_ALM_IRQ,
+		.flags = IORESOURCE_IRQ,
+	},
+};
+
+static const struct mfd_cell lp8788_devs[] = {
+	/* 4 bucks */
+	MFD_DEV_WITH_ID(BUCK, 1),
+	MFD_DEV_WITH_ID(BUCK, 2),
+	MFD_DEV_WITH_ID(BUCK, 3),
+	MFD_DEV_WITH_ID(BUCK, 4),
+
+	/* 12 digital ldos */
+	MFD_DEV_WITH_ID(DLDO, 1),
+	MFD_DEV_WITH_ID(DLDO, 2),
+	MFD_DEV_WITH_ID(DLDO, 3),
+	MFD_DEV_WITH_ID(DLDO, 4),
+	MFD_DEV_WITH_ID(DLDO, 5),
+	MFD_DEV_WITH_ID(DLDO, 6),
+	MFD_DEV_WITH_ID(DLDO, 7),
+	MFD_DEV_WITH_ID(DLDO, 8),
+	MFD_DEV_WITH_ID(DLDO, 9),
+	MFD_DEV_WITH_ID(DLDO, 10),
+	MFD_DEV_WITH_ID(DLDO, 11),
+	MFD_DEV_WITH_ID(DLDO, 12),
+
+	/* 10 analog ldos */
+	MFD_DEV_WITH_ID(ALDO, 1),
+	MFD_DEV_WITH_ID(ALDO, 2),
+	MFD_DEV_WITH_ID(ALDO, 3),
+	MFD_DEV_WITH_ID(ALDO, 4),
+	MFD_DEV_WITH_ID(ALDO, 5),
+	MFD_DEV_WITH_ID(ALDO, 6),
+	MFD_DEV_WITH_ID(ALDO, 7),
+	MFD_DEV_WITH_ID(ALDO, 8),
+	MFD_DEV_WITH_ID(ALDO, 9),
+	MFD_DEV_WITH_ID(ALDO, 10),
+
+	/* ADC */
+	MFD_DEV_SIMPLE(ADC),
+
+	/* battery charger */
+	MFD_DEV_WITH_RESOURCE(CHARGER, chg_irqs, ARRAY_SIZE(chg_irqs)),
+
+	/* rtc */
+	MFD_DEV_WITH_RESOURCE(RTC, rtc_irqs, ARRAY_SIZE(rtc_irqs)),
+
+	/* backlight */
+	MFD_DEV_SIMPLE(BACKLIGHT),
+
+	/* current sink for vibrator */
+	MFD_DEV_SIMPLE(VIBRATOR),
+
+	/* current sink for keypad LED */
+	MFD_DEV_SIMPLE(KEYLED),
+};
+
+int lp8788_read_byte(struct lp8788 *lp, u8 reg, u8 *data)
+{
+	int ret;
+	unsigned int val;
+
+	ret = regmap_read(lp->regmap, reg, &val);
+	if (ret < 0) {
+		dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
+		return ret;
+	}
+
+	*data = (u8)val;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(lp8788_read_byte);
+
+int lp8788_read_multi_bytes(struct lp8788 *lp, u8 reg, u8 *data, size_t count)
+{
+	return regmap_bulk_read(lp->regmap, reg, data, count);
+}
+EXPORT_SYMBOL_GPL(lp8788_read_multi_bytes);
+
+int lp8788_write_byte(struct lp8788 *lp, u8 reg, u8 data)
+{
+	return regmap_write(lp->regmap, reg, data);
+}
+EXPORT_SYMBOL_GPL(lp8788_write_byte);
+
+int lp8788_update_bits(struct lp8788 *lp, u8 reg, u8 mask, u8 data)
+{
+	return regmap_update_bits(lp->regmap, reg, mask, data);
+}
+EXPORT_SYMBOL_GPL(lp8788_update_bits);
+
+static int lp8788_platform_init(struct lp8788 *lp)
+{
+	struct lp8788_platform_data *pdata = lp->pdata;
+
+	return (pdata && pdata->init_func) ? pdata->init_func(lp) : 0;
+}
+
+static const struct regmap_config lp8788_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX_LP8788_REGISTERS,
+};
+
+static int lp8788_probe(struct i2c_client *cl)
+{
+	struct lp8788 *lp;
+	struct lp8788_platform_data *pdata = dev_get_platdata(&cl->dev);
+	int ret;
+
+	lp = devm_kzalloc(&cl->dev, sizeof(struct lp8788), GFP_KERNEL);
+	if (!lp)
+		return -ENOMEM;
+
+	lp->regmap = devm_regmap_init_i2c(cl, &lp8788_regmap_config);
+	if (IS_ERR(lp->regmap)) {
+		ret = PTR_ERR(lp->regmap);
+		dev_err(&cl->dev, "regmap init i2c err: %d\n", ret);
+		return ret;
+	}
+
+	lp->pdata = pdata;
+	lp->dev = &cl->dev;
+	i2c_set_clientdata(cl, lp);
+
+	ret = lp8788_platform_init(lp);
+	if (ret)
+		return ret;
+
+	ret = lp8788_irq_init(lp, cl->irq);
+	if (ret)
+		return ret;
+
+	ret = mfd_add_devices(lp->dev, -1, lp8788_devs,
+			      ARRAY_SIZE(lp8788_devs), NULL, 0, NULL);
+	if (ret)
+		goto err_exit_irq;
+
+	return 0;
+
+err_exit_irq:
+	lp8788_irq_exit(lp);
+	return ret;
+}
+
+static void lp8788_remove(struct i2c_client *cl)
+{
+	struct lp8788 *lp = i2c_get_clientdata(cl);
+
+	mfd_remove_devices(lp->dev);
+	lp8788_irq_exit(lp);
+}
+
+static const struct i2c_device_id lp8788_ids[] = {
+	{ "lp8788" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lp8788_ids);
+
+static struct i2c_driver lp8788_driver = {
+	.driver = {
+		.name = "lp8788",
+	},
+	.probe = lp8788_probe,
+	.remove = lp8788_remove,
+	.id_table = lp8788_ids,
+};
+
+static int __init lp8788_init(void)
+{
+	return i2c_add_driver(&lp8788_driver);
+}
+subsys_initcall(lp8788_init);
+
+static void __exit lp8788_exit(void)
+{
+	i2c_del_driver(&lp8788_driver);
+}
+module_exit(lp8788_exit);
+
+MODULE_DESCRIPTION("TI LP8788 MFD Driver");
+MODULE_AUTHOR("Milo Kim");