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, 244 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/cdns3-starfive.c b/drivers/usb/cdns3/cdns3-starfive.c
new file mode 100644
index 000000000..2ff7f2b48
--- /dev/null
+++ b/drivers/usb/cdns3/cdns3-starfive.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * cdns3-starfive.c - StarFive specific Glue layer for Cadence USB Controller
+ *
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ *
+ * Author:	Minda Chen <minda.chen@starfivetech.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/of_platform.h>
+#include <linux/reset.h>
+#include <linux/regmap.h>
+#include <linux/usb/otg.h>
+#include "core.h"
+
+#define USB_STRAP_HOST			BIT(17)
+#define USB_STRAP_DEVICE		BIT(18)
+#define USB_STRAP_MASK			GENMASK(18, 16)
+
+#define USB_SUSPENDM_HOST		BIT(19)
+#define USB_SUSPENDM_MASK		BIT(19)
+
+#define USB_MISC_CFG_MASK		GENMASK(23, 20)
+#define USB_SUSPENDM_BYPS		BIT(20)
+#define USB_PLL_EN			BIT(22)
+#define USB_REFCLK_MODE			BIT(23)
+
+struct cdns_starfive {
+	struct device *dev;
+	struct regmap *stg_syscon;
+	struct reset_control *resets;
+	struct clk_bulk_data *clks;
+	int num_clks;
+	u32 stg_usb_mode;
+};
+
+static void cdns_mode_init(struct platform_device *pdev,
+			   struct cdns_starfive *data)
+{
+	enum usb_dr_mode mode;
+
+	regmap_update_bits(data->stg_syscon, data->stg_usb_mode,
+			   USB_MISC_CFG_MASK,
+			   USB_SUSPENDM_BYPS | USB_PLL_EN | USB_REFCLK_MODE);
+
+	/* dr mode setting */
+	mode = usb_get_dr_mode(&pdev->dev);
+
+	switch (mode) {
+	case USB_DR_MODE_HOST:
+		regmap_update_bits(data->stg_syscon,
+				   data->stg_usb_mode,
+				   USB_STRAP_MASK,
+				   USB_STRAP_HOST);
+		regmap_update_bits(data->stg_syscon,
+				   data->stg_usb_mode,
+				   USB_SUSPENDM_MASK,
+				   USB_SUSPENDM_HOST);
+		break;
+
+	case USB_DR_MODE_PERIPHERAL:
+		regmap_update_bits(data->stg_syscon, data->stg_usb_mode,
+				   USB_STRAP_MASK, USB_STRAP_DEVICE);
+		regmap_update_bits(data->stg_syscon, data->stg_usb_mode,
+				   USB_SUSPENDM_MASK, 0);
+		break;
+	default:
+		break;
+	}
+}
+
+static int cdns_clk_rst_init(struct cdns_starfive *data)
+{
+	int ret;
+
+	ret = clk_bulk_prepare_enable(data->num_clks, data->clks);
+	if (ret)
+		return dev_err_probe(data->dev, ret,
+				     "failed to enable clocks\n");
+
+	ret = reset_control_deassert(data->resets);
+	if (ret) {
+		dev_err(data->dev, "failed to reset clocks\n");
+		goto err_clk_init;
+	}
+
+	return ret;
+
+err_clk_init:
+	clk_bulk_disable_unprepare(data->num_clks, data->clks);
+	return ret;
+}
+
+static void cdns_clk_rst_deinit(struct cdns_starfive *data)
+{
+	reset_control_assert(data->resets);
+	clk_bulk_disable_unprepare(data->num_clks, data->clks);
+}
+
+static int cdns_starfive_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cdns_starfive *data;
+	unsigned int args;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->dev = dev;
+
+	data->stg_syscon =
+		syscon_regmap_lookup_by_phandle_args(pdev->dev.of_node,
+						     "starfive,stg-syscon", 1, &args);
+
+	if (IS_ERR(data->stg_syscon))
+		return dev_err_probe(dev, PTR_ERR(data->stg_syscon),
+				     "Failed to parse starfive,stg-syscon\n");
+
+	data->stg_usb_mode = args;
+
+	data->num_clks = devm_clk_bulk_get_all(data->dev, &data->clks);
+	if (data->num_clks < 0)
+		return dev_err_probe(data->dev, -ENODEV,
+				     "Failed to get clocks\n");
+
+	data->resets = devm_reset_control_array_get_exclusive(data->dev);
+	if (IS_ERR(data->resets))
+		return dev_err_probe(data->dev, PTR_ERR(data->resets),
+				     "Failed to get resets");
+
+	cdns_mode_init(pdev, data);
+	ret = cdns_clk_rst_init(data);
+	if (ret)
+		return ret;
+
+	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "Failed to create children\n");
+		cdns_clk_rst_deinit(data);
+		return ret;
+	}
+
+	device_set_wakeup_capable(dev, true);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static int cdns_starfive_remove_core(struct device *dev, void *c)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	platform_device_unregister(pdev);
+
+	return 0;
+}
+
+static void cdns_starfive_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cdns_starfive *data = dev_get_drvdata(dev);
+
+	pm_runtime_get_sync(dev);
+	device_for_each_child(dev, NULL, cdns_starfive_remove_core);
+
+	pm_runtime_disable(dev);
+	pm_runtime_put_noidle(dev);
+	cdns_clk_rst_deinit(data);
+	platform_set_drvdata(pdev, NULL);
+}
+
+#ifdef CONFIG_PM
+static int cdns_starfive_runtime_resume(struct device *dev)
+{
+	struct cdns_starfive *data = dev_get_drvdata(dev);
+
+	return clk_bulk_prepare_enable(data->num_clks, data->clks);
+}
+
+static int cdns_starfive_runtime_suspend(struct device *dev)
+{
+	struct cdns_starfive *data = dev_get_drvdata(dev);
+
+	clk_bulk_disable_unprepare(data->num_clks, data->clks);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int cdns_starfive_resume(struct device *dev)
+{
+	struct cdns_starfive *data = dev_get_drvdata(dev);
+
+	return cdns_clk_rst_init(data);
+}
+
+static int cdns_starfive_suspend(struct device *dev)
+{
+	struct cdns_starfive *data = dev_get_drvdata(dev);
+
+	cdns_clk_rst_deinit(data);
+
+	return 0;
+}
+#endif
+#endif
+
+static const struct dev_pm_ops cdns_starfive_pm_ops = {
+	SET_RUNTIME_PM_OPS(cdns_starfive_runtime_suspend,
+			   cdns_starfive_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(cdns_starfive_suspend, cdns_starfive_resume)
+};
+
+static const struct of_device_id cdns_starfive_of_match[] = {
+	{ .compatible = "starfive,jh7110-usb", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, cdns_starfive_of_match);
+
+static struct platform_driver cdns_starfive_driver = {
+	.probe		= cdns_starfive_probe,
+	.remove		= cdns_starfive_remove,
+	.driver		= {
+		.name	= "cdns3-starfive",
+		.of_match_table	= cdns_starfive_of_match,
+		.pm	= &cdns_starfive_pm_ops,
+	},
+};
+module_platform_driver(cdns_starfive_driver);
+
+MODULE_ALIAS("platform:cdns3-starfive");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Cadence USB3 StarFive Glue Layer");