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, 133 insertions, 0 deletions

diff --git a/drivers/mfd/rt5033.c b/drivers/mfd/rt5033.c
new file mode 100644
index 000000000..072fd4447
--- /dev/null
+++ b/drivers/mfd/rt5033.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MFD core driver for the Richtek RT5033.
+ *
+ * RT5033 comprises multiple sub-devices switcing charger, fuel gauge,
+ * flash LED, current source, LDO and BUCK regulators.
+ *
+ * Copyright (C) 2014 Samsung Electronics, Co., Ltd.
+ * Author: Beomho Seo <beomho.seo@samsung.com>
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/rt5033.h>
+#include <linux/mfd/rt5033-private.h>
+
+static const struct regmap_irq rt5033_irqs[] = {
+	{ .mask = RT5033_PMIC_IRQ_BUCKOCP, },
+	{ .mask = RT5033_PMIC_IRQ_BUCKLV, },
+	{ .mask = RT5033_PMIC_IRQ_SAFELDOLV, },
+	{ .mask = RT5033_PMIC_IRQ_LDOLV, },
+	{ .mask = RT5033_PMIC_IRQ_OT, },
+	{ .mask = RT5033_PMIC_IRQ_VDDA_UV, },
+};
+
+static const struct regmap_irq_chip rt5033_irq_chip = {
+	.name		= "rt5033",
+	.status_base	= RT5033_REG_PMIC_IRQ_STAT,
+	.unmask_base	= RT5033_REG_PMIC_IRQ_CTRL,
+	.num_regs	= 1,
+	.irqs		= rt5033_irqs,
+	.num_irqs	= ARRAY_SIZE(rt5033_irqs),
+};
+
+static const struct mfd_cell rt5033_devs[] = {
+	{ .name = "rt5033-regulator", },
+	{
+		.name = "rt5033-charger",
+		.of_compatible = "richtek,rt5033-charger",
+	}, {
+		.name = "rt5033-led",
+		.of_compatible = "richtek,rt5033-led",
+	},
+};
+
+static const struct regmap_config rt5033_regmap_config = {
+	.reg_bits	= 8,
+	.val_bits	= 8,
+	.max_register	= RT5033_REG_END,
+};
+
+static int rt5033_i2c_probe(struct i2c_client *i2c)
+{
+	struct rt5033_dev *rt5033;
+	unsigned int dev_id, chip_rev;
+	int ret;
+
+	rt5033 = devm_kzalloc(&i2c->dev, sizeof(*rt5033), GFP_KERNEL);
+	if (!rt5033)
+		return -ENOMEM;
+
+	i2c_set_clientdata(i2c, rt5033);
+	rt5033->dev = &i2c->dev;
+	rt5033->irq = i2c->irq;
+	rt5033->wakeup = true;
+
+	rt5033->regmap = devm_regmap_init_i2c(i2c, &rt5033_regmap_config);
+	if (IS_ERR(rt5033->regmap)) {
+		dev_err(&i2c->dev, "Failed to allocate register map.\n");
+		return PTR_ERR(rt5033->regmap);
+	}
+
+	ret = regmap_read(rt5033->regmap, RT5033_REG_DEVICE_ID, &dev_id);
+	if (ret) {
+		dev_err(&i2c->dev, "Device not found\n");
+		return -ENODEV;
+	}
+	chip_rev = dev_id & RT5033_CHIP_REV_MASK;
+	dev_info(&i2c->dev, "Device found (rev. %d)\n", chip_rev);
+
+	ret = devm_regmap_add_irq_chip(rt5033->dev, rt5033->regmap,
+			rt5033->irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+			0, &rt5033_irq_chip, &rt5033->irq_data);
+	if (ret) {
+		dev_err(&i2c->dev, "Failed to request IRQ %d: %d\n",
+							rt5033->irq, ret);
+		return ret;
+	}
+
+	ret = devm_mfd_add_devices(rt5033->dev, -1, rt5033_devs,
+				   ARRAY_SIZE(rt5033_devs), NULL, 0,
+				   regmap_irq_get_domain(rt5033->irq_data));
+	if (ret < 0) {
+		dev_err(&i2c->dev, "Failed to add RT5033 child devices.\n");
+		return ret;
+	}
+
+	if (rt5033->wakeup) {
+		ret = devm_device_init_wakeup(rt5033->dev);
+		if (ret)
+			return dev_err_probe(rt5033->dev, ret, "Failed to init wakeup\n");
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id rt5033_i2c_id[] = {
+	{ "rt5033", },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rt5033_i2c_id);
+
+static const struct of_device_id rt5033_dt_match[] = {
+	{ .compatible = "richtek,rt5033", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rt5033_dt_match);
+
+static struct i2c_driver rt5033_driver = {
+	.driver = {
+		.name = "rt5033",
+		.of_match_table = rt5033_dt_match,
+	},
+	.probe = rt5033_i2c_probe,
+	.id_table = rt5033_i2c_id,
+};
+module_i2c_driver(rt5033_driver);
+
+MODULE_DESCRIPTION("Richtek RT5033 multi-function core driver");
+MODULE_AUTHOR("Beomho Seo <beomho.seo@samsung.com>");
+MODULE_LICENSE("GPL");