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, 353 insertions, 0 deletions

diff --git a/drivers/reset/reset-rzg2l-usbphy-ctrl.c b/drivers/reset/reset-rzg2l-usbphy-ctrl.c
new file mode 100644
index 000000000..f003b3606
--- /dev/null
+++ b/drivers/reset/reset-rzg2l-usbphy-ctrl.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/G2L USBPHY control driver
+ *
+ * Copyright (C) 2021 Renesas Electronics Corporation
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/reset-controller.h>
+#include <linux/mfd/syscon.h>
+
+#define RESET			0x000
+#define VBENCTL			0x03c
+
+#define RESET_SEL_PLLRESET	BIT(12)
+#define RESET_PLLRESET		BIT(8)
+
+#define RESET_SEL_P2RESET	BIT(5)
+#define RESET_SEL_P1RESET	BIT(4)
+#define RESET_PHYRST_2		BIT(1)
+#define RESET_PHYRST_1		BIT(0)
+
+#define PHY_RESET_PORT2		(RESET_SEL_P2RESET | RESET_PHYRST_2)
+#define PHY_RESET_PORT1		(RESET_SEL_P1RESET | RESET_PHYRST_1)
+
+#define NUM_PORTS		2
+
+struct rzg2l_usbphy_ctrl_priv {
+	struct reset_controller_dev rcdev;
+	struct reset_control *rstc;
+	void __iomem *base;
+	struct platform_device *vdev;
+	struct regmap_field *pwrrdy;
+
+	spinlock_t lock;
+};
+
+#define rcdev_to_priv(x)	container_of(x, struct rzg2l_usbphy_ctrl_priv, rcdev)
+
+static int rzg2l_usbphy_ctrl_assert(struct reset_controller_dev *rcdev,
+				    unsigned long id)
+{
+	struct rzg2l_usbphy_ctrl_priv *priv = rcdev_to_priv(rcdev);
+	u32 port_mask = PHY_RESET_PORT1 | PHY_RESET_PORT2;
+	void __iomem *base = priv->base;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	val = readl(base + RESET);
+	val |= id ? PHY_RESET_PORT2 : PHY_RESET_PORT1;
+	if (port_mask == (val & port_mask))
+		val |= RESET_PLLRESET;
+	writel(val, base + RESET);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int rzg2l_usbphy_ctrl_deassert(struct reset_controller_dev *rcdev,
+				      unsigned long id)
+{
+	struct rzg2l_usbphy_ctrl_priv *priv = rcdev_to_priv(rcdev);
+	void __iomem *base = priv->base;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	val = readl(base + RESET);
+
+	val |= RESET_SEL_PLLRESET;
+	val &= ~(RESET_PLLRESET | (id ? PHY_RESET_PORT2 : PHY_RESET_PORT1));
+	writel(val, base + RESET);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int rzg2l_usbphy_ctrl_status(struct reset_controller_dev *rcdev,
+				    unsigned long id)
+{
+	struct rzg2l_usbphy_ctrl_priv *priv = rcdev_to_priv(rcdev);
+	u32 port_mask;
+
+	port_mask = id ? PHY_RESET_PORT2 : PHY_RESET_PORT1;
+
+	return !!(readl(priv->base + RESET) & port_mask);
+}
+
+/* put pll and phy into reset state */
+static void rzg2l_usbphy_ctrl_init(struct rzg2l_usbphy_ctrl_priv *priv)
+{
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	val = readl(priv->base + RESET);
+	val |= RESET_SEL_PLLRESET | RESET_PLLRESET | PHY_RESET_PORT2 | PHY_RESET_PORT1;
+	writel(val, priv->base + RESET);
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+#define RZG2L_USBPHY_CTRL_PWRRDY	1
+
+static const struct of_device_id rzg2l_usbphy_ctrl_match_table[] = {
+	{ .compatible = "renesas,rzg2l-usbphy-ctrl" },
+	{
+		.compatible = "renesas,r9a08g045-usbphy-ctrl",
+		.data = (void *)RZG2L_USBPHY_CTRL_PWRRDY
+	},
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzg2l_usbphy_ctrl_match_table);
+
+static const struct reset_control_ops rzg2l_usbphy_ctrl_reset_ops = {
+	.assert = rzg2l_usbphy_ctrl_assert,
+	.deassert = rzg2l_usbphy_ctrl_deassert,
+	.status = rzg2l_usbphy_ctrl_status,
+};
+
+static const struct regmap_config rzg2l_usb_regconf = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = 1,
+};
+
+static int rzg2l_usbphy_ctrl_set_pwrrdy(struct regmap_field *pwrrdy,
+					bool power_on)
+{
+	u32 val = power_on ? 0 : 1;
+
+	if (!pwrrdy)
+		return 0;
+
+	/* The initialization path guarantees that the mask is 1 bit long. */
+	return regmap_field_update_bits(pwrrdy, 1, val);
+}
+
+static void rzg2l_usbphy_ctrl_pwrrdy_off(void *data)
+{
+	rzg2l_usbphy_ctrl_set_pwrrdy(data, false);
+}
+
+static int rzg2l_usbphy_ctrl_pwrrdy_init(struct device *dev,
+					 struct rzg2l_usbphy_ctrl_priv *priv)
+{
+	struct reg_field field;
+	struct regmap *regmap;
+	const int *data;
+	u32 args[2];
+	int ret;
+
+	data = device_get_match_data(dev);
+	if ((uintptr_t)data != RZG2L_USBPHY_CTRL_PWRRDY)
+		return 0;
+
+	regmap = syscon_regmap_lookup_by_phandle_args(dev->of_node,
+						      "renesas,sysc-pwrrdy",
+						      ARRAY_SIZE(args), args);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	/* Don't allow more than one bit in mask. */
+	if (hweight32(args[1]) != 1)
+		return -EINVAL;
+
+	field.reg = args[0];
+	field.lsb = __ffs(args[1]);
+	field.msb = __fls(args[1]);
+
+	priv->pwrrdy = devm_regmap_field_alloc(dev, regmap, field);
+	if (IS_ERR(priv->pwrrdy))
+		return PTR_ERR(priv->pwrrdy);
+
+	ret = rzg2l_usbphy_ctrl_set_pwrrdy(priv->pwrrdy, true);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, rzg2l_usbphy_ctrl_pwrrdy_off, priv->pwrrdy);
+}
+
+static int rzg2l_usbphy_ctrl_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rzg2l_usbphy_ctrl_priv *priv;
+	struct platform_device *vdev;
+	struct regmap *regmap;
+	int error;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	regmap = devm_regmap_init_mmio(dev, priv->base + VBENCTL, &rzg2l_usb_regconf);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	error = rzg2l_usbphy_ctrl_pwrrdy_init(dev, priv);
+	if (error)
+		return error;
+
+	priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(priv->rstc))
+		return dev_err_probe(dev, PTR_ERR(priv->rstc),
+				     "failed to get reset\n");
+
+	error = reset_control_deassert(priv->rstc);
+	if (error)
+		return error;
+
+	spin_lock_init(&priv->lock);
+	dev_set_drvdata(dev, priv);
+
+	pm_runtime_enable(&pdev->dev);
+	error = pm_runtime_resume_and_get(&pdev->dev);
+	if (error < 0) {
+		dev_err_probe(&pdev->dev, error, "pm_runtime_resume_and_get failed");
+		goto err_pm_disable_reset_deassert;
+	}
+
+	rzg2l_usbphy_ctrl_init(priv);
+
+	priv->rcdev.ops = &rzg2l_usbphy_ctrl_reset_ops;
+	priv->rcdev.of_reset_n_cells = 1;
+	priv->rcdev.nr_resets = NUM_PORTS;
+	priv->rcdev.of_node = dev->of_node;
+	priv->rcdev.dev = dev;
+
+	error = devm_reset_controller_register(dev, &priv->rcdev);
+	if (error)
+		goto err_pm_runtime_put;
+
+	vdev = platform_device_alloc("rzg2l-usb-vbus-regulator", pdev->id);
+	if (!vdev) {
+		error = -ENOMEM;
+		goto err_pm_runtime_put;
+	}
+	vdev->dev.parent = dev;
+	priv->vdev = vdev;
+
+	platform_device_set_of_node_from_dev(vdev, dev);
+	error = platform_device_add(vdev);
+	if (error)
+		goto err_device_put;
+
+	return 0;
+
+err_device_put:
+	platform_device_put(vdev);
+err_pm_runtime_put:
+	pm_runtime_put(&pdev->dev);
+err_pm_disable_reset_deassert:
+	pm_runtime_disable(&pdev->dev);
+	reset_control_assert(priv->rstc);
+	return error;
+}
+
+static void rzg2l_usbphy_ctrl_remove(struct platform_device *pdev)
+{
+	struct rzg2l_usbphy_ctrl_priv *priv = dev_get_drvdata(&pdev->dev);
+
+	platform_device_unregister(priv->vdev);
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	reset_control_assert(priv->rstc);
+}
+
+static int rzg2l_usbphy_ctrl_suspend(struct device *dev)
+{
+	struct rzg2l_usbphy_ctrl_priv *priv = dev_get_drvdata(dev);
+	u32 val;
+	int ret;
+
+	val = readl(priv->base + RESET);
+	if (!(val & PHY_RESET_PORT2) || !(val & PHY_RESET_PORT1))
+		WARN(1, "Suspend with resets de-asserted\n");
+
+	pm_runtime_put_sync(dev);
+
+	ret = reset_control_assert(priv->rstc);
+	if (ret)
+		goto rpm_resume;
+
+	ret = rzg2l_usbphy_ctrl_set_pwrrdy(priv->pwrrdy, false);
+	if (ret)
+		goto reset_deassert;
+
+	return 0;
+
+reset_deassert:
+	reset_control_deassert(priv->rstc);
+rpm_resume:
+	pm_runtime_resume_and_get(dev);
+	return ret;
+}
+
+static int rzg2l_usbphy_ctrl_resume(struct device *dev)
+{
+	struct rzg2l_usbphy_ctrl_priv *priv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = rzg2l_usbphy_ctrl_set_pwrrdy(priv->pwrrdy, true);
+	if (ret)
+		return ret;
+
+	ret = reset_control_deassert(priv->rstc);
+	if (ret)
+		goto pwrrdy_off;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret)
+		goto reset_assert;
+
+	rzg2l_usbphy_ctrl_init(priv);
+
+	return 0;
+
+reset_assert:
+	reset_control_assert(priv->rstc);
+pwrrdy_off:
+	rzg2l_usbphy_ctrl_set_pwrrdy(priv->pwrrdy, false);
+	return ret;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(rzg2l_usbphy_ctrl_pm_ops,
+				rzg2l_usbphy_ctrl_suspend,
+				rzg2l_usbphy_ctrl_resume);
+
+static struct platform_driver rzg2l_usbphy_ctrl_driver = {
+	.driver = {
+		.name		= "rzg2l_usbphy_ctrl",
+		.of_match_table	= rzg2l_usbphy_ctrl_match_table,
+		.pm		= pm_ptr(&rzg2l_usbphy_ctrl_pm_ops),
+	},
+	.probe	= rzg2l_usbphy_ctrl_probe,
+	.remove = rzg2l_usbphy_ctrl_remove,
+};
+module_platform_driver(rzg2l_usbphy_ctrl_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Renesas RZ/G2L USBPHY Control");
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");