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, 287 insertions, 0 deletions

diff --git a/drivers/phy/qualcomm/phy-qcom-usb-hs.c b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
new file mode 100644
index 000000000..928a982a8
--- /dev/null
+++ b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Linaro Ltd
+ */
+#include <linux/module.h>
+#include <linux/ulpi/driver.h>
+#include <linux/ulpi/regs.h>
+#include <linux/clk.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/reset.h>
+#include <linux/extcon.h>
+#include <linux/notifier.h>
+
+#define ULPI_PWR_CLK_MNG_REG		0x88
+# define ULPI_PWR_OTG_COMP_DISABLE	BIT(0)
+
+#define ULPI_MISC_A			0x96
+# define ULPI_MISC_A_VBUSVLDEXTSEL	BIT(1)
+# define ULPI_MISC_A_VBUSVLDEXT		BIT(0)
+
+
+struct ulpi_seq {
+	u8 addr;
+	u8 val;
+};
+
+struct qcom_usb_hs_phy {
+	struct ulpi *ulpi;
+	struct phy *phy;
+	struct clk *ref_clk;
+	struct clk *sleep_clk;
+	struct regulator *v1p8;
+	struct regulator *v3p3;
+	struct reset_control *reset;
+	struct extcon_dev *vbus_edev;
+	struct notifier_block vbus_notify;
+	struct ulpi_seq init_seq[];
+};
+
+static int qcom_usb_hs_phy_set_mode(struct phy *phy,
+				    enum phy_mode mode, int submode)
+{
+	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+	u8 addr;
+	int ret;
+
+	if (!uphy->vbus_edev) {
+		u8 val = 0;
+
+		switch (mode) {
+		case PHY_MODE_USB_OTG:
+		case PHY_MODE_USB_HOST:
+			val |= ULPI_INT_IDGRD;
+			fallthrough;
+		case PHY_MODE_USB_DEVICE:
+			val |= ULPI_INT_SESS_VALID;
+			break;
+		default:
+			break;
+		}
+
+		ret = ulpi_write(uphy->ulpi, ULPI_USB_INT_EN_RISE, val);
+		if (ret)
+			return ret;
+		ret = ulpi_write(uphy->ulpi, ULPI_USB_INT_EN_FALL, val);
+	} else {
+		switch (mode) {
+		case PHY_MODE_USB_OTG:
+		case PHY_MODE_USB_DEVICE:
+			addr = ULPI_SET(ULPI_MISC_A);
+			break;
+		case PHY_MODE_USB_HOST:
+			addr = ULPI_CLR(ULPI_MISC_A);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		ret = ulpi_write(uphy->ulpi, ULPI_SET(ULPI_PWR_CLK_MNG_REG),
+				 ULPI_PWR_OTG_COMP_DISABLE);
+		if (ret)
+			return ret;
+		ret = ulpi_write(uphy->ulpi, addr, ULPI_MISC_A_VBUSVLDEXTSEL);
+	}
+
+	return ret;
+}
+
+static int
+qcom_usb_hs_phy_vbus_notifier(struct notifier_block *nb, unsigned long event,
+			      void *ptr)
+{
+	struct qcom_usb_hs_phy *uphy;
+	u8 addr;
+
+	uphy = container_of(nb, struct qcom_usb_hs_phy, vbus_notify);
+
+	if (event)
+		addr = ULPI_SET(ULPI_MISC_A);
+	else
+		addr = ULPI_CLR(ULPI_MISC_A);
+
+	return ulpi_write(uphy->ulpi, addr, ULPI_MISC_A_VBUSVLDEXT);
+}
+
+static int qcom_usb_hs_phy_power_on(struct phy *phy)
+{
+	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+	struct ulpi *ulpi = uphy->ulpi;
+	const struct ulpi_seq *seq;
+	int ret, state;
+
+	ret = clk_prepare_enable(uphy->ref_clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(uphy->sleep_clk);
+	if (ret)
+		goto err_sleep;
+
+	ret = regulator_set_load(uphy->v1p8, 50000);
+	if (ret < 0)
+		goto err_1p8;
+
+	ret = regulator_enable(uphy->v1p8);
+	if (ret)
+		goto err_1p8;
+
+	ret = regulator_set_voltage_triplet(uphy->v3p3, 3050000, 3300000,
+					    3300000);
+	if (ret)
+		goto err_3p3;
+
+	ret = regulator_set_load(uphy->v3p3, 50000);
+	if (ret < 0)
+		goto err_3p3;
+
+	ret = regulator_enable(uphy->v3p3);
+	if (ret)
+		goto err_3p3;
+
+	for (seq = uphy->init_seq; seq->addr; seq++) {
+		ret = ulpi_write(ulpi, ULPI_EXT_VENDOR_SPECIFIC + seq->addr,
+				 seq->val);
+		if (ret)
+			goto err_ulpi;
+	}
+
+	if (uphy->reset) {
+		ret = reset_control_reset(uphy->reset);
+		if (ret)
+			goto err_ulpi;
+	}
+
+	if (uphy->vbus_edev) {
+		state = extcon_get_state(uphy->vbus_edev, EXTCON_USB);
+		/* setup initial state */
+		qcom_usb_hs_phy_vbus_notifier(&uphy->vbus_notify, state,
+					      uphy->vbus_edev);
+		ret = extcon_register_notifier(uphy->vbus_edev, EXTCON_USB,
+					       &uphy->vbus_notify);
+		if (ret)
+			goto err_ulpi;
+	}
+
+	return 0;
+err_ulpi:
+	regulator_disable(uphy->v3p3);
+err_3p3:
+	regulator_disable(uphy->v1p8);
+err_1p8:
+	clk_disable_unprepare(uphy->sleep_clk);
+err_sleep:
+	clk_disable_unprepare(uphy->ref_clk);
+	return ret;
+}
+
+static int qcom_usb_hs_phy_power_off(struct phy *phy)
+{
+	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+
+	if (uphy->vbus_edev)
+		extcon_unregister_notifier(uphy->vbus_edev, EXTCON_USB,
+					   &uphy->vbus_notify);
+	regulator_disable(uphy->v3p3);
+	regulator_disable(uphy->v1p8);
+	clk_disable_unprepare(uphy->sleep_clk);
+	clk_disable_unprepare(uphy->ref_clk);
+
+	return 0;
+}
+
+static const struct phy_ops qcom_usb_hs_phy_ops = {
+	.power_on = qcom_usb_hs_phy_power_on,
+	.power_off = qcom_usb_hs_phy_power_off,
+	.set_mode = qcom_usb_hs_phy_set_mode,
+	.owner = THIS_MODULE,
+};
+
+static int qcom_usb_hs_phy_probe(struct ulpi *ulpi)
+{
+	struct qcom_usb_hs_phy *uphy;
+	struct phy_provider *p;
+	struct clk *clk;
+	struct regulator *reg;
+	struct reset_control *reset;
+	int size;
+	int ret;
+
+	size = of_property_count_u8_elems(ulpi->dev.of_node, "qcom,init-seq");
+	if (size < 0)
+		size = 0;
+
+	uphy = devm_kzalloc(&ulpi->dev, struct_size(uphy, init_seq, (size / 2) + 1), GFP_KERNEL);
+	if (!uphy)
+		return -ENOMEM;
+	ulpi_set_drvdata(ulpi, uphy);
+	uphy->ulpi = ulpi;
+
+	ret = of_property_read_u8_array(ulpi->dev.of_node, "qcom,init-seq",
+					(u8 *)uphy->init_seq, size);
+	if (ret && size)
+		return ret;
+	/* NUL terminate */
+	uphy->init_seq[size / 2].addr = uphy->init_seq[size / 2].val = 0;
+
+	uphy->ref_clk = clk = devm_clk_get(&ulpi->dev, "ref");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->sleep_clk = clk = devm_clk_get(&ulpi->dev, "sleep");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->v1p8 = reg = devm_regulator_get(&ulpi->dev, "v1p8");
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	uphy->v3p3 = reg = devm_regulator_get(&ulpi->dev, "v3p3");
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	uphy->reset = reset = devm_reset_control_get(&ulpi->dev, "por");
+	if (IS_ERR(reset)) {
+		if (PTR_ERR(reset) == -EPROBE_DEFER)
+			return PTR_ERR(reset);
+		uphy->reset = NULL;
+	}
+
+	uphy->phy = devm_phy_create(&ulpi->dev, ulpi->dev.of_node,
+				    &qcom_usb_hs_phy_ops);
+	if (IS_ERR(uphy->phy))
+		return PTR_ERR(uphy->phy);
+
+	uphy->vbus_edev = extcon_get_edev_by_phandle(&ulpi->dev, 0);
+	if (IS_ERR(uphy->vbus_edev)) {
+		if (PTR_ERR(uphy->vbus_edev) != -ENODEV)
+			return PTR_ERR(uphy->vbus_edev);
+		uphy->vbus_edev = NULL;
+	}
+
+	uphy->vbus_notify.notifier_call = qcom_usb_hs_phy_vbus_notifier;
+	phy_set_drvdata(uphy->phy, uphy);
+
+	p = devm_of_phy_provider_register(&ulpi->dev, of_phy_simple_xlate);
+	return PTR_ERR_OR_ZERO(p);
+}
+
+static const struct of_device_id qcom_usb_hs_phy_match[] = {
+	{ .compatible = "qcom,usb-hs-phy", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_usb_hs_phy_match);
+
+static struct ulpi_driver qcom_usb_hs_phy_driver = {
+	.probe = qcom_usb_hs_phy_probe,
+	.driver = {
+		.name = "qcom_usb_hs_phy",
+		.of_match_table = qcom_usb_hs_phy_match,
+	},
+};
+module_ulpi_driver(qcom_usb_hs_phy_driver);
+
+MODULE_DESCRIPTION("Qualcomm USB HS phy");
+MODULE_LICENSE("GPL v2");