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, 215 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinctrl-max7360.c b/drivers/pinctrl/pinctrl-max7360.c
new file mode 100644
index 000000000..abfaff468
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-max7360.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 Bootlin
+ *
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/array_size.h>
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/device/devres.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/mfd/max7360.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/stddef.h>
+
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinmux.h>
+
+#include "core.h"
+#include "pinmux.h"
+
+struct max7360_pinctrl {
+	struct pinctrl_dev *pctldev;
+	struct pinctrl_desc pinctrl_desc;
+};
+
+static const struct pinctrl_pin_desc max7360_pins[] = {
+	PINCTRL_PIN(0, "PORT0"),
+	PINCTRL_PIN(1, "PORT1"),
+	PINCTRL_PIN(2, "PORT2"),
+	PINCTRL_PIN(3, "PORT3"),
+	PINCTRL_PIN(4, "PORT4"),
+	PINCTRL_PIN(5, "PORT5"),
+	PINCTRL_PIN(6, "PORT6"),
+	PINCTRL_PIN(7, "PORT7"),
+};
+
+static const unsigned int port0_pins[] = {0};
+static const unsigned int port1_pins[] = {1};
+static const unsigned int port2_pins[] = {2};
+static const unsigned int port3_pins[] = {3};
+static const unsigned int port4_pins[] = {4};
+static const unsigned int port5_pins[] = {5};
+static const unsigned int port6_pins[] = {6};
+static const unsigned int port7_pins[] = {7};
+static const unsigned int rotary_pins[] = {6, 7};
+
+static const struct pingroup max7360_groups[] = {
+	PINCTRL_PINGROUP("PORT0", port0_pins, ARRAY_SIZE(port0_pins)),
+	PINCTRL_PINGROUP("PORT1", port1_pins, ARRAY_SIZE(port1_pins)),
+	PINCTRL_PINGROUP("PORT2", port2_pins, ARRAY_SIZE(port2_pins)),
+	PINCTRL_PINGROUP("PORT3", port3_pins, ARRAY_SIZE(port3_pins)),
+	PINCTRL_PINGROUP("PORT4", port4_pins, ARRAY_SIZE(port4_pins)),
+	PINCTRL_PINGROUP("PORT5", port5_pins, ARRAY_SIZE(port5_pins)),
+	PINCTRL_PINGROUP("PORT6", port6_pins, ARRAY_SIZE(port6_pins)),
+	PINCTRL_PINGROUP("PORT7", port7_pins, ARRAY_SIZE(port7_pins)),
+	PINCTRL_PINGROUP("ROTARY", rotary_pins, ARRAY_SIZE(rotary_pins)),
+};
+
+static int max7360_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(max7360_groups);
+}
+
+static const char *max7360_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
+						  unsigned int group)
+{
+	return max7360_groups[group].name;
+}
+
+static int max7360_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
+					  unsigned int group,
+					  const unsigned int **pins,
+					  unsigned int *num_pins)
+{
+	*pins = max7360_groups[group].pins;
+	*num_pins = max7360_groups[group].npins;
+	return 0;
+}
+
+static const struct pinctrl_ops max7360_pinctrl_ops = {
+	.get_groups_count = max7360_pinctrl_get_groups_count,
+	.get_group_name = max7360_pinctrl_get_group_name,
+	.get_group_pins = max7360_pinctrl_get_group_pins,
+#ifdef CONFIG_OF
+	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
+	.dt_free_map = pinconf_generic_dt_free_map,
+#endif
+};
+
+static const char * const simple_groups[] = {
+	"PORT0", "PORT1", "PORT2", "PORT3",
+	"PORT4", "PORT5", "PORT6", "PORT7",
+};
+
+static const char * const rotary_groups[] = { "ROTARY" };
+
+#define MAX7360_PINCTRL_FN_GPIO		0
+#define MAX7360_PINCTRL_FN_PWM		1
+#define MAX7360_PINCTRL_FN_ROTARY	2
+static const struct pinfunction max7360_functions[] = {
+	[MAX7360_PINCTRL_FN_GPIO] = PINCTRL_PINFUNCTION("gpio", simple_groups,
+							ARRAY_SIZE(simple_groups)),
+	[MAX7360_PINCTRL_FN_PWM] = PINCTRL_PINFUNCTION("pwm", simple_groups,
+						       ARRAY_SIZE(simple_groups)),
+	[MAX7360_PINCTRL_FN_ROTARY] = PINCTRL_PINFUNCTION("rotary", rotary_groups,
+							  ARRAY_SIZE(rotary_groups)),
+};
+
+static int max7360_get_functions_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(max7360_functions);
+}
+
+static const char *max7360_get_function_name(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	return max7360_functions[selector].name;
+}
+
+static int max7360_get_function_groups(struct pinctrl_dev *pctldev, unsigned int selector,
+				       const char * const **groups,
+				       unsigned int * const num_groups)
+{
+	*groups = max7360_functions[selector].groups;
+	*num_groups = max7360_functions[selector].ngroups;
+
+	return 0;
+}
+
+static int max7360_set_mux(struct pinctrl_dev *pctldev, unsigned int selector,
+			   unsigned int group)
+{
+	struct regmap *regmap = dev_get_regmap(pctldev->dev->parent, NULL);
+	int val;
+
+	/*
+	 * GPIO and PWM functions are the same: we only need to handle the
+	 * rotary encoder function, on pins 6 and 7.
+	 */
+	if (max7360_groups[group].pins[0] >= 6) {
+		if (selector == MAX7360_PINCTRL_FN_ROTARY)
+			val = MAX7360_GPIO_CFG_RTR_EN;
+		else
+			val = 0;
+
+		return regmap_write_bits(regmap, MAX7360_REG_GPIOCFG, MAX7360_GPIO_CFG_RTR_EN, val);
+	}
+
+	return 0;
+}
+
+static const struct pinmux_ops max7360_pmxops = {
+	.get_functions_count = max7360_get_functions_count,
+	.get_function_name = max7360_get_function_name,
+	.get_function_groups = max7360_get_function_groups,
+	.set_mux = max7360_set_mux,
+	.strict = true,
+};
+
+static int max7360_pinctrl_probe(struct platform_device *pdev)
+{
+	struct regmap *regmap;
+	struct pinctrl_desc *pd;
+	struct max7360_pinctrl *chip;
+	struct device *dev = &pdev->dev;
+
+	regmap = dev_get_regmap(dev->parent, NULL);
+	if (!regmap)
+		return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	pd = &chip->pinctrl_desc;
+
+	pd->pctlops = &max7360_pinctrl_ops;
+	pd->pmxops = &max7360_pmxops;
+	pd->name = dev_name(dev);
+	pd->pins = max7360_pins;
+	pd->npins = MAX7360_MAX_GPIO;
+	pd->owner = THIS_MODULE;
+
+	/*
+	 * This MFD sub-device does not have any associated device tree node:
+	 * properties are stored in the device node of the parent (MFD) device
+	 * and this same node is used in phandles of client devices.
+	 * Reuse this device tree node here, as otherwise the pinctrl subsystem
+	 * would be confused by this topology.
+	 */
+	device_set_of_node_from_dev(dev, dev->parent);
+
+	chip->pctldev = devm_pinctrl_register(dev, pd, chip);
+	if (IS_ERR(chip->pctldev))
+		return dev_err_probe(dev, PTR_ERR(chip->pctldev), "can't register controller\n");
+
+	return 0;
+}
+
+static struct platform_driver max7360_pinctrl_driver = {
+	.driver = {
+		.name	= "max7360-pinctrl",
+	},
+	.probe		= max7360_pinctrl_probe,
+};
+module_platform_driver(max7360_pinctrl_driver);
+
+MODULE_DESCRIPTION("MAX7360 pinctrl driver");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
+MODULE_LICENSE("GPL");