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/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
new file mode 100644
index 000000000..e7366fcb7
--- /dev/null
+++ b/drivers/acpi/acpi_apd.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD ACPI support for ACPI2platform device.
+ *
+ * Copyright (c) 2014,2015 AMD Corporation.
+ * Authors: Ken Xue <Ken.Xue@amd.com>
+ *	Wu, Jeff <Jeff.Wu@amd.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/platform_data/clk-fch.h>
+#include <linux/platform_device.h>
+#include <linux/units.h>
+
+#include "internal.h"
+
+struct apd_private_data;
+
+/**
+ * struct apd_device_desc - a descriptor for apd device
+ * @fixed_clk_rate: fixed rate input clock source for acpi device;
+ *			0 means no fixed rate input clock source
+ * @properties: build-in properties of the device such as UART
+ * @setup: a hook routine to set device resource during create platform device
+ *
+ * Device description defined as acpi_device_id.driver_data
+ */
+struct apd_device_desc {
+	unsigned int fixed_clk_rate;
+	struct property_entry *properties;
+	int (*setup)(struct apd_private_data *pdata);
+};
+
+struct apd_private_data {
+	struct clk *clk;
+	struct acpi_device *adev;
+	const struct apd_device_desc *dev_desc;
+};
+
+#if defined(CONFIG_X86_AMD_PLATFORM_DEVICE) || defined(CONFIG_ARM64)
+#define APD_ADDR(desc)	((unsigned long)&desc)
+
+static int acpi_apd_setup(struct apd_private_data *pdata)
+{
+	const struct apd_device_desc *dev_desc = pdata->dev_desc;
+	struct clk *clk;
+
+	if (dev_desc->fixed_clk_rate) {
+		clk = clk_register_fixed_rate(&pdata->adev->dev,
+					dev_name(&pdata->adev->dev),
+					NULL, 0, dev_desc->fixed_clk_rate);
+		clk_register_clkdev(clk, NULL, dev_name(&pdata->adev->dev));
+		pdata->clk = clk;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_X86_AMD_PLATFORM_DEVICE
+
+static int fch_misc_setup(struct apd_private_data *pdata)
+{
+	struct acpi_device *adev = pdata->adev;
+	const union acpi_object *obj;
+	struct platform_device *clkdev;
+	struct fch_clk_data *clk_data;
+	struct resource_entry *rentry;
+	struct list_head resource_list;
+	int ret;
+
+	clk_data = devm_kzalloc(&adev->dev, sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_memory_resources(adev, &resource_list);
+	if (ret < 0)
+		return -ENOENT;
+
+	if (!acpi_dev_get_property(adev, "clk-name", ACPI_TYPE_STRING, &obj)) {
+		clk_data->name = devm_kzalloc(&adev->dev, obj->string.length,
+					      GFP_KERNEL);
+		if (!clk_data->name)
+			return -ENOMEM;
+
+		strscpy(clk_data->name, obj->string.pointer, obj->string.length);
+	} else {
+		/* Set default name to mclk if entry missing in firmware */
+		clk_data->name = "mclk";
+	}
+
+	list_for_each_entry(rentry, &resource_list, node) {
+		clk_data->base = devm_ioremap(&adev->dev, rentry->res->start,
+					      resource_size(rentry->res));
+		break;
+	}
+	if (!clk_data->base)
+		return -ENOMEM;
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	clkdev = platform_device_register_data(&adev->dev, "clk-fch",
+					       PLATFORM_DEVID_NONE, clk_data,
+					       sizeof(*clk_data));
+	return PTR_ERR_OR_ZERO(clkdev);
+}
+
+static const struct apd_device_desc cz_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 133 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc wt_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 150 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc wt_i3c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125 * HZ_PER_MHZ,
+};
+
+static struct property_entry uart_properties[] = {
+	PROPERTY_ENTRY_U32("reg-io-width", 4),
+	PROPERTY_ENTRY_U32("reg-shift", 2),
+	PROPERTY_ENTRY_BOOL("snps,uart-16550-compatible"),
+	{ },
+};
+
+static const struct apd_device_desc cz_uart_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 48 * HZ_PER_MHZ,
+	.properties = uart_properties,
+};
+
+static const struct apd_device_desc fch_misc_desc = {
+	.setup = fch_misc_setup,
+};
+#endif /* CONFIG_X86_AMD_PLATFORM_DEVICE */
+
+#ifdef CONFIG_ARM64
+static const struct apd_device_desc xgene_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 100 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc vulcan_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 133 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip07_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 200 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip08_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 250 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip08_lite_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc thunderx2_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc nxp_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 350 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hip08_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 250 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc leca_spi_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 400 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc leca_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 250 * HZ_PER_MHZ,
+};
+
+static const struct apd_device_desc hjmc_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 200 * HZ_PER_MHZ,
+};
+
+#endif /* CONFIG_ARM64 */
+
+#endif
+
+/*
+ * Create platform device during acpi scan attach handle.
+ * Return value > 0 on success of creating device.
+ */
+static int acpi_apd_create_device(struct acpi_device *adev,
+				   const struct acpi_device_id *id)
+{
+	const struct apd_device_desc *dev_desc = (void *)id->driver_data;
+	struct apd_private_data *pdata;
+	struct platform_device *pdev;
+	int ret;
+
+	if (!dev_desc) {
+		pdev = acpi_create_platform_device(adev, NULL);
+		return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
+	}
+
+	pdata = kzalloc_obj(*pdata);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->adev = adev;
+	pdata->dev_desc = dev_desc;
+
+	if (dev_desc->setup) {
+		ret = dev_desc->setup(pdata);
+		if (ret)
+			goto err_out;
+	}
+
+	adev->driver_data = pdata;
+	pdev = acpi_create_platform_device(adev, dev_desc->properties);
+	if (!IS_ERR_OR_NULL(pdev))
+		return 1;
+
+	ret = PTR_ERR(pdev);
+	adev->driver_data = NULL;
+
+ err_out:
+	kfree(pdata);
+	return ret;
+}
+
+static const struct acpi_device_id acpi_apd_device_ids[] = {
+	/* Generic apd devices */
+#ifdef CONFIG_X86_AMD_PLATFORM_DEVICE
+	{ "AMD0010", APD_ADDR(cz_i2c_desc) },
+	{ "AMD0020", APD_ADDR(cz_uart_desc) },
+	{ "AMD0030", },
+	{ "AMD0040", APD_ADDR(fch_misc_desc)},
+	{ "AMDI0010", APD_ADDR(wt_i2c_desc) },
+	{ "AMDI0015", APD_ADDR(wt_i3c_desc) },
+	{ "AMDI0019", APD_ADDR(wt_i2c_desc) },
+	{ "AMDI0020", APD_ADDR(cz_uart_desc) },
+	{ "AMDI0022", APD_ADDR(cz_uart_desc) },
+	{ "HYGO0010", APD_ADDR(wt_i2c_desc) },
+#endif
+#ifdef CONFIG_ARM64
+	{ "APMC0D0F", APD_ADDR(xgene_i2c_desc) },
+	{ "BRCM900D", APD_ADDR(vulcan_spi_desc) },
+	{ "CAV900D",  APD_ADDR(vulcan_spi_desc) },
+	{ "CAV9007",  APD_ADDR(thunderx2_i2c_desc) },
+	{ "HISI02A1", APD_ADDR(hip07_i2c_desc) },
+	{ "HISI02A2", APD_ADDR(hip08_i2c_desc) },
+	{ "HISI02A3", APD_ADDR(hip08_lite_i2c_desc) },
+	{ "HISI0173", APD_ADDR(hip08_spi_desc) },
+	{ "HJMC3001", APD_ADDR(hjmc_i2c_desc) },
+	{ "LECA0002", APD_ADDR(leca_spi_desc) },
+	{ "LECA0003", APD_ADDR(leca_i2c_desc) },
+	{ "NXP0001", APD_ADDR(nxp_i2c_desc) },
+#endif
+	{ }
+};
+
+static struct acpi_scan_handler apd_handler = {
+	.ids = acpi_apd_device_ids,
+	.attach = acpi_apd_create_device,
+};
+
+void __init acpi_apd_init(void)
+{
+	acpi_scan_add_handler(&apd_handler);
+}