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, 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");