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, 365 insertions, 0 deletions

diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
new file mode 100644
index 000000000..1c2fe3f91
--- /dev/null
+++ b/drivers/mfd/tqmx86.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * TQ-Systems PLD MFD core driver, based on vendor driver by
+ * Vadim V.Vlasov <vvlasov@dev.rtsoft.ru>
+ *
+ * Copyright (c) 2015 TQ-Systems GmbH
+ * Copyright (c) 2019 Andrew Lunn <andrew@lunn.ch>
+ */
+
+#include <linux/delay.h>
+#include <linux/dmi.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/platform_data/i2c-ocores.h>
+#include <linux/platform_device.h>
+
+#define TQMX86_IOBASE	0x180
+#define TQMX86_IOSIZE	0x20
+#define TQMX86_IOBASE_I2C	0x1a0
+#define TQMX86_IOSIZE_I2C	0xa
+#define TQMX86_IOBASE_WATCHDOG	0x18b
+#define TQMX86_IOSIZE_WATCHDOG	0x2
+#define TQMX86_IOBASE_GPIO	0x18d
+#define TQMX86_IOSIZE_GPIO	0x4
+
+#define TQMX86_REG_BOARD_ID	0x00
+#define TQMX86_REG_BOARD_ID_E38M	1
+#define TQMX86_REG_BOARD_ID_50UC	2
+#define TQMX86_REG_BOARD_ID_E38C	3
+#define TQMX86_REG_BOARD_ID_60EB	4
+#define TQMX86_REG_BOARD_ID_E39MS	5
+#define TQMX86_REG_BOARD_ID_E39C1	6
+#define TQMX86_REG_BOARD_ID_E39C2	7
+#define TQMX86_REG_BOARD_ID_70EB	8
+#define TQMX86_REG_BOARD_ID_80UC	9
+#define TQMX86_REG_BOARD_ID_120UC	10
+#define TQMX86_REG_BOARD_ID_110EB	11
+#define TQMX86_REG_BOARD_ID_E40M	12
+#define TQMX86_REG_BOARD_ID_E40S	13
+#define TQMX86_REG_BOARD_ID_E40C1	14
+#define TQMX86_REG_BOARD_ID_E40C2	15
+#define TQMX86_REG_BOARD_ID_130UC	16
+#define TQMX86_REG_BOARD_ID_E41S	19
+#define TQMX86_REG_BOARD_ID_CU1_HPCM	24
+#define TQMX86_REG_BOARD_ID_CU2_HPCM	25
+#define TQMX86_REG_BOARD_REV	0x01
+#define TQMX86_REG_IO_EXT_INT	0x06
+#define TQMX86_REG_IO_EXT_INT_NONE		0
+#define TQMX86_REG_IO_EXT_INT_7			1
+#define TQMX86_REG_IO_EXT_INT_9			2
+#define TQMX86_REG_IO_EXT_INT_12		3
+#define TQMX86_REG_IO_EXT_INT_MASK		0x3
+#define TQMX86_REG_IO_EXT_INT_I2C1_SHIFT	0
+#define TQMX86_REG_IO_EXT_INT_GPIO_SHIFT	4
+#define TQMX86_REG_SAUC		0x17
+
+#define TQMX86_REG_I2C_DETECT	0x1a7
+#define TQMX86_REG_I2C_DETECT_SOFT		0xa5
+
+static uint gpio_irq;
+module_param(gpio_irq, uint, 0);
+MODULE_PARM_DESC(gpio_irq, "GPIO IRQ number (valid parameters: 7, 9, 12)");
+
+static uint i2c1_irq;
+module_param(i2c1_irq, uint, 0);
+MODULE_PARM_DESC(i2c1_irq, "I2C1 IRQ number (valid parameters: 7, 9, 12)");
+
+enum tqmx86_i2c1_resource_type {
+	TQMX86_I2C1_IO,
+	TQMX86_I2C1_IRQ,
+};
+
+static struct resource tqmx_i2c_soft_resources[] = {
+	[TQMX86_I2C1_IO] = DEFINE_RES_IO(TQMX86_IOBASE_I2C, TQMX86_IOSIZE_I2C),
+	/* Placeholder for IRQ resource */
+	[TQMX86_I2C1_IRQ] = {},
+};
+
+static const struct resource tqmx_watchdog_resources[] = {
+	DEFINE_RES_IO(TQMX86_IOBASE_WATCHDOG, TQMX86_IOSIZE_WATCHDOG),
+};
+
+enum tqmx86_gpio_resource_type {
+	TQMX86_GPIO_IO,
+	TQMX86_GPIO_IRQ,
+};
+
+static struct resource tqmx_gpio_resources[] = {
+	[TQMX86_GPIO_IO] = DEFINE_RES_IO(TQMX86_IOBASE_GPIO, TQMX86_IOSIZE_GPIO),
+	/* Placeholder for IRQ resource */
+	[TQMX86_GPIO_IRQ] = {},
+};
+
+static struct i2c_board_info tqmx86_i2c_devices[] = {
+	{
+		/* 4K EEPROM at 0x50 */
+		I2C_BOARD_INFO("24c32", 0x50),
+	},
+};
+
+static struct ocores_i2c_platform_data ocores_platform_data = {
+	.num_devices = ARRAY_SIZE(tqmx86_i2c_devices),
+	.devices = tqmx86_i2c_devices,
+};
+
+static const struct mfd_cell tqmx86_i2c_soft_dev[] = {
+	{
+		.name = "ocores-i2c",
+		.platform_data = &ocores_platform_data,
+		.pdata_size = sizeof(ocores_platform_data),
+		.resources = tqmx_i2c_soft_resources,
+		.num_resources = ARRAY_SIZE(tqmx_i2c_soft_resources),
+	},
+};
+
+static const struct mfd_cell tqmx86_devs[] = {
+	{
+		.name = "tqmx86-wdt",
+		.resources = tqmx_watchdog_resources,
+		.num_resources = ARRAY_SIZE(tqmx_watchdog_resources),
+		.ignore_resource_conflicts = true,
+	},
+	{
+		.name = "tqmx86-gpio",
+		.resources = tqmx_gpio_resources,
+		.num_resources = ARRAY_SIZE(tqmx_gpio_resources),
+		.ignore_resource_conflicts = true,
+	},
+};
+
+static const char *tqmx86_board_id_to_name(u8 board_id, u8 sauc)
+{
+	switch (board_id) {
+	case TQMX86_REG_BOARD_ID_E38M:
+		return "TQMxE38M";
+	case TQMX86_REG_BOARD_ID_50UC:
+		return "TQMx50UC";
+	case TQMX86_REG_BOARD_ID_E38C:
+		return "TQMxE38C";
+	case TQMX86_REG_BOARD_ID_60EB:
+		return "TQMx60EB";
+	case TQMX86_REG_BOARD_ID_E39MS:
+		return (sauc == 0xff) ? "TQMxE39M" : "TQMxE39S";
+	case TQMX86_REG_BOARD_ID_E39C1:
+		return "TQMxE39C1";
+	case TQMX86_REG_BOARD_ID_E39C2:
+		return "TQMxE39C2";
+	case TQMX86_REG_BOARD_ID_70EB:
+		return "TQMx70EB";
+	case TQMX86_REG_BOARD_ID_80UC:
+		return "TQMx80UC";
+	case TQMX86_REG_BOARD_ID_120UC:
+		return "TQMx120UC";
+	case TQMX86_REG_BOARD_ID_110EB:
+		return "TQMx110EB";
+	case TQMX86_REG_BOARD_ID_E40M:
+		return "TQMxE40M";
+	case TQMX86_REG_BOARD_ID_E40S:
+		return "TQMxE40S";
+	case TQMX86_REG_BOARD_ID_E40C1:
+		return "TQMxE40C1";
+	case TQMX86_REG_BOARD_ID_E40C2:
+		return "TQMxE40C2";
+	case TQMX86_REG_BOARD_ID_130UC:
+		return "TQMx130UC";
+	case TQMX86_REG_BOARD_ID_E41S:
+		return "TQMxE41S";
+	case TQMX86_REG_BOARD_ID_CU1_HPCM:
+		return "TQMxCU1-HPCM";
+	case TQMX86_REG_BOARD_ID_CU2_HPCM:
+		return "TQMxCU2-HPCM";
+	default:
+		return "Unknown";
+	}
+}
+
+static int tqmx86_board_id_to_clk_rate(struct device *dev, u8 board_id)
+{
+	switch (board_id) {
+	case TQMX86_REG_BOARD_ID_50UC:
+	case TQMX86_REG_BOARD_ID_60EB:
+	case TQMX86_REG_BOARD_ID_70EB:
+	case TQMX86_REG_BOARD_ID_80UC:
+	case TQMX86_REG_BOARD_ID_120UC:
+	case TQMX86_REG_BOARD_ID_110EB:
+	case TQMX86_REG_BOARD_ID_E40M:
+	case TQMX86_REG_BOARD_ID_E40S:
+	case TQMX86_REG_BOARD_ID_E40C1:
+	case TQMX86_REG_BOARD_ID_E40C2:
+	case TQMX86_REG_BOARD_ID_130UC:
+	case TQMX86_REG_BOARD_ID_E41S:
+	case TQMX86_REG_BOARD_ID_CU1_HPCM:
+	case TQMX86_REG_BOARD_ID_CU2_HPCM:
+		return 24000;
+	case TQMX86_REG_BOARD_ID_E39MS:
+	case TQMX86_REG_BOARD_ID_E39C1:
+	case TQMX86_REG_BOARD_ID_E39C2:
+		return 25000;
+	case TQMX86_REG_BOARD_ID_E38M:
+	case TQMX86_REG_BOARD_ID_E38C:
+		return 33000;
+	default:
+		dev_warn(dev, "unknown board %d, assuming 24MHz LPC clock\n",
+			 board_id);
+		return 24000;
+	}
+}
+
+static int tqmx86_setup_irq(struct device *dev, const char *label, u8 irq,
+			    void __iomem *io_base, u8 reg_shift)
+{
+	u8 val, readback;
+	int irq_cfg;
+
+	switch (irq) {
+	case 0:
+		irq_cfg = TQMX86_REG_IO_EXT_INT_NONE;
+		break;
+	case 7:
+		irq_cfg = TQMX86_REG_IO_EXT_INT_7;
+		break;
+	case 9:
+		irq_cfg = TQMX86_REG_IO_EXT_INT_9;
+		break;
+	case 12:
+		irq_cfg = TQMX86_REG_IO_EXT_INT_12;
+		break;
+	default:
+		dev_err(dev, "invalid %s IRQ (%d)\n", label, irq);
+		return -EINVAL;
+	}
+
+	val = ioread8(io_base + TQMX86_REG_IO_EXT_INT);
+	val &= ~(TQMX86_REG_IO_EXT_INT_MASK << reg_shift);
+	val |= (irq_cfg & TQMX86_REG_IO_EXT_INT_MASK) << reg_shift;
+
+	iowrite8(val, io_base + TQMX86_REG_IO_EXT_INT);
+	readback = ioread8(io_base + TQMX86_REG_IO_EXT_INT);
+	if (readback != val) {
+		dev_warn(dev, "%s interrupts not supported\n", label);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int tqmx86_probe(struct platform_device *pdev)
+{
+	u8 board_id, sauc, rev, i2c_det;
+	struct device *dev = &pdev->dev;
+	const char *board_name;
+	void __iomem *io_base;
+	int err;
+
+	io_base = devm_ioport_map(dev, TQMX86_IOBASE, TQMX86_IOSIZE);
+	if (!io_base)
+		return -ENOMEM;
+
+	board_id = ioread8(io_base + TQMX86_REG_BOARD_ID);
+	sauc = ioread8(io_base + TQMX86_REG_SAUC);
+	board_name = tqmx86_board_id_to_name(board_id, sauc);
+	rev = ioread8(io_base + TQMX86_REG_BOARD_REV);
+
+	dev_info(dev,
+		 "Found %s - Board ID %d, PCB Revision %d, PLD Revision %d\n",
+		 board_name, board_id, rev >> 4, rev & 0xf);
+
+	/*
+	 * The I2C_DETECT register is in the range assigned to the I2C driver
+	 * later, so we don't extend TQMX86_IOSIZE. Use inb() for this one-off
+	 * access instead of ioport_map + unmap.
+	 */
+	i2c_det = inb(TQMX86_REG_I2C_DETECT);
+
+	if (gpio_irq) {
+		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
+				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
+		if (!err)
+			tqmx_gpio_resources[TQMX86_GPIO_IRQ] = DEFINE_RES_IRQ(gpio_irq);
+	}
+
+	ocores_platform_data.clock_khz = tqmx86_board_id_to_clk_rate(dev, board_id);
+
+	if (i2c_det == TQMX86_REG_I2C_DETECT_SOFT) {
+		if (i2c1_irq) {
+			err = tqmx86_setup_irq(dev, "I2C1", i2c1_irq, io_base,
+					       TQMX86_REG_IO_EXT_INT_I2C1_SHIFT);
+			if (!err)
+				tqmx_i2c_soft_resources[TQMX86_I2C1_IRQ] = DEFINE_RES_IRQ(i2c1_irq);
+		}
+
+		err = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+					   tqmx86_i2c_soft_dev,
+					   ARRAY_SIZE(tqmx86_i2c_soft_dev),
+					   NULL, 0, NULL);
+		if (err)
+			return err;
+	}
+
+	return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				    tqmx86_devs,
+				    ARRAY_SIZE(tqmx86_devs),
+				    NULL, 0, NULL);
+}
+
+static int tqmx86_create_platform_device(const struct dmi_system_id *id)
+{
+	struct platform_device *pdev;
+	int err;
+
+	pdev = platform_device_alloc("tqmx86", -1);
+	if (!pdev)
+		return -ENOMEM;
+
+	err = platform_device_add(pdev);
+	if (err)
+		platform_device_put(pdev);
+
+	return err;
+}
+
+static const struct dmi_system_id tqmx86_dmi_table[] __initconst = {
+	{
+		.ident = "TQMX86",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "TQ-Group"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "TQMx"),
+		},
+		.callback = tqmx86_create_platform_device,
+	},
+	{
+		.ident = "TQMX86",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "TQ-Systems"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "TQMx"),
+		},
+		.callback = tqmx86_create_platform_device,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, tqmx86_dmi_table);
+
+static struct platform_driver tqmx86_driver = {
+	.driver		= {
+		.name	= "tqmx86",
+	},
+	.probe		= tqmx86_probe,
+};
+
+static int __init tqmx86_init(void)
+{
+	if (!dmi_check_system(tqmx86_dmi_table))
+		return -ENODEV;
+
+	return platform_driver_register(&tqmx86_driver);
+}
+
+module_init(tqmx86_init);
+
+MODULE_DESCRIPTION("TQMx86 PLD Core Driver");
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:tqmx86");