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, 412 insertions, 0 deletions

diff --git a/drivers/firmware/xilinx/zynqmp-debug.c b/drivers/firmware/xilinx/zynqmp-debug.c
new file mode 100644
index 000000000..36efb827f
--- /dev/null
+++ b/drivers/firmware/xilinx/zynqmp-debug.c
@@ -0,0 +1,412 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Zynq MPSoC Firmware layer for debugfs APIs
+ *
+ *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *  Copyright (C) 2022 - 2025 Advanced Micro Devices, Inc.
+ *
+ *  Michal Simek <michal.simek@amd.com>
+ *  Davorin Mista <davorin.mista@aggios.com>
+ *  Jolly Shah <jollys@xilinx.com>
+ *  Rajan Vaja <rajanv@xilinx.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+#include <linux/firmware/xlnx-zynqmp.h>
+#include "zynqmp-debug.h"
+
+#define PM_API_NAME_LEN			50
+
+struct pm_api_info {
+	u32 api_id;
+	char api_name[PM_API_NAME_LEN];
+	char api_name_len;
+};
+
+static char debugfs_buf[PAGE_SIZE];
+
+#define PM_API(id)		 {id, #id, strlen(#id)}
+static struct pm_api_info pm_api_list[] = {
+	PM_API(PM_FORCE_POWERDOWN),
+	PM_API(PM_REQUEST_WAKEUP),
+	PM_API(PM_SYSTEM_SHUTDOWN),
+	PM_API(PM_REQUEST_NODE),
+	PM_API(PM_RELEASE_NODE),
+	PM_API(PM_SET_REQUIREMENT),
+	PM_API(PM_GET_API_VERSION),
+	PM_API(PM_GET_NODE_STATUS),
+	PM_API(PM_REGISTER_NOTIFIER),
+	PM_API(PM_RESET_ASSERT),
+	PM_API(PM_RESET_GET_STATUS),
+	PM_API(PM_GET_CHIPID),
+	PM_API(PM_PINCTRL_SET_FUNCTION),
+	PM_API(PM_PINCTRL_CONFIG_PARAM_GET),
+	PM_API(PM_PINCTRL_CONFIG_PARAM_SET),
+	PM_API(PM_IOCTL),
+	PM_API(PM_CLOCK_ENABLE),
+	PM_API(PM_CLOCK_DISABLE),
+	PM_API(PM_CLOCK_GETSTATE),
+	PM_API(PM_CLOCK_SETDIVIDER),
+	PM_API(PM_CLOCK_GETDIVIDER),
+	PM_API(PM_CLOCK_SETPARENT),
+	PM_API(PM_CLOCK_GETPARENT),
+	PM_API(PM_QUERY_DATA),
+};
+
+static struct dentry *firmware_debugfs_root;
+
+/**
+ * zynqmp_pm_ioctl - PM IOCTL for device control and configs
+ * @node:	Node ID of the device
+ * @ioctl:	ID of the requested IOCTL
+ * @arg1:	Argument 1 of requested IOCTL call
+ * @arg2:	Argument 2 of requested IOCTL call
+ * @arg3:	Argument 3 of requested IOCTL call
+ * @out:	Returned output value
+ *
+ * Return:	Returns status, either success or error+reason
+ */
+static int zynqmp_pm_ioctl(const u32 node, const u32 ioctl, const u32 arg1,
+			   const u32 arg2, const u32 arg3, u32 *out)
+{
+	return zynqmp_pm_invoke_fn(PM_IOCTL, out, 5, node, ioctl, arg1, arg2, arg3);
+}
+
+/**
+ * zynqmp_pm_argument_value() - Extract argument value from a PM-API request
+ * @arg:	Entered PM-API argument in string format
+ *
+ * Return: Argument value in unsigned integer format on success
+ *	   0 otherwise
+ */
+static u64 zynqmp_pm_argument_value(char *arg)
+{
+	u64 value;
+
+	if (!arg)
+		return 0;
+
+	if (!kstrtou64(arg, 0, &value))
+		return value;
+
+	return 0;
+}
+
+/**
+ * get_pm_api_id() - Extract API-ID from a PM-API request
+ * @pm_api_req:		Entered PM-API argument in string format
+ * @pm_id:		API-ID
+ *
+ * Return: 0 on success else error code
+ */
+static int get_pm_api_id(char *pm_api_req, u32 *pm_id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pm_api_list) ; i++) {
+		if (!strncasecmp(pm_api_req, pm_api_list[i].api_name,
+				 pm_api_list[i].api_name_len)) {
+			*pm_id = pm_api_list[i].api_id;
+			break;
+		}
+	}
+
+	/* If no name was entered look for PM-API ID instead */
+	if (i == ARRAY_SIZE(pm_api_list) && kstrtouint(pm_api_req, 10, pm_id))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int process_api_request(u32 pm_id, u64 *pm_api_arg, u32 *pm_api_ret)
+{
+	u32 pm_api_version;
+	int ret;
+	struct zynqmp_pm_query_data qdata = {0};
+
+	switch (pm_id) {
+	case PM_GET_API_VERSION:
+		ret = zynqmp_pm_get_api_version(&pm_api_version);
+		sprintf(debugfs_buf, "PM-API Version = %d.%d\n",
+			pm_api_version >> 16, pm_api_version & 0xffff);
+		break;
+	case PM_FORCE_POWERDOWN:
+		ret = zynqmp_pm_force_pwrdwn(pm_api_arg[0],
+					     pm_api_arg[1] ? pm_api_arg[1] :
+					     ZYNQMP_PM_REQUEST_ACK_NO);
+		break;
+	case PM_REQUEST_WAKEUP:
+		ret = zynqmp_pm_request_wake(pm_api_arg[0],
+					     pm_api_arg[1], pm_api_arg[2],
+					     pm_api_arg[3] ? pm_api_arg[3] :
+					     ZYNQMP_PM_REQUEST_ACK_NO);
+		break;
+	case PM_SYSTEM_SHUTDOWN:
+		ret = zynqmp_pm_system_shutdown(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_REQUEST_NODE:
+		ret = zynqmp_pm_request_node(pm_api_arg[0],
+					     pm_api_arg[1] ? pm_api_arg[1] :
+					     ZYNQMP_PM_CAPABILITY_ACCESS,
+					     pm_api_arg[2] ? pm_api_arg[2] : 0,
+					     pm_api_arg[3] ? pm_api_arg[3] :
+					     ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		break;
+	case PM_RELEASE_NODE:
+		ret = zynqmp_pm_release_node(pm_api_arg[0]);
+		break;
+	case PM_SET_REQUIREMENT:
+		ret = zynqmp_pm_set_requirement(pm_api_arg[0],
+						pm_api_arg[1] ? pm_api_arg[1] :
+						ZYNQMP_PM_CAPABILITY_CONTEXT,
+						pm_api_arg[2] ?
+						pm_api_arg[2] : 0,
+						pm_api_arg[3] ? pm_api_arg[3] :
+						ZYNQMP_PM_REQUEST_ACK_BLOCKING);
+		break;
+	case PM_GET_NODE_STATUS:
+		ret = zynqmp_pm_get_node_status(pm_api_arg[0],
+						&pm_api_ret[0],
+						&pm_api_ret[1],
+						&pm_api_ret[2]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"GET_NODE_STATUS:\n\tNodeId: %llu\n\tStatus: %u\n\tRequirements: %u\n\tUsage: %u\n",
+				pm_api_arg[0], pm_api_ret[0],
+				pm_api_ret[1], pm_api_ret[2]);
+		break;
+	case PM_REGISTER_NOTIFIER:
+		ret = zynqmp_pm_register_notifier(pm_api_arg[0],
+						  pm_api_arg[1] ?
+						  pm_api_arg[1] : 0,
+						  pm_api_arg[2] ?
+						  pm_api_arg[2] : 0,
+						  pm_api_arg[3] ?
+						  pm_api_arg[3] : 0);
+		break;
+	case PM_RESET_ASSERT:
+		ret = zynqmp_pm_reset_assert(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_RESET_GET_STATUS:
+		ret = zynqmp_pm_reset_get_status(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf, "Reset status: %u\n",
+				pm_api_ret[0]);
+		break;
+	case PM_GET_CHIPID:
+		ret = zynqmp_pm_get_chipid(&pm_api_ret[0], &pm_api_ret[1]);
+		if (!ret)
+			sprintf(debugfs_buf, "Idcode: %#x, Version:%#x\n",
+				pm_api_ret[0], pm_api_ret[1]);
+		break;
+	case PM_PINCTRL_SET_FUNCTION:
+		ret = zynqmp_pm_pinctrl_set_function(pm_api_arg[0],
+						     pm_api_arg[1]);
+		break;
+	case PM_PINCTRL_CONFIG_PARAM_GET:
+		ret = zynqmp_pm_pinctrl_get_config(pm_api_arg[0], pm_api_arg[1],
+						   &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"Pin: %llu, Param: %llu, Value: %u\n",
+				pm_api_arg[0], pm_api_arg[1],
+				pm_api_ret[0]);
+		break;
+	case PM_PINCTRL_CONFIG_PARAM_SET:
+		ret = zynqmp_pm_pinctrl_set_config(pm_api_arg[0],
+						   pm_api_arg[1],
+						   pm_api_arg[2]);
+		break;
+	case PM_IOCTL:
+		ret = zynqmp_pm_ioctl(pm_api_arg[0], pm_api_arg[1],
+				      pm_api_arg[2], pm_api_arg[3],
+				      pm_api_arg[4], &pm_api_ret[0]);
+		if (!ret && (pm_api_arg[1] == IOCTL_GET_RPU_OPER_MODE ||
+			     pm_api_arg[1] == IOCTL_GET_PLL_FRAC_MODE ||
+			     pm_api_arg[1] == IOCTL_GET_PLL_FRAC_DATA ||
+			     pm_api_arg[1] == IOCTL_READ_GGS ||
+			     pm_api_arg[1] == IOCTL_READ_PGGS ||
+			     pm_api_arg[1] == IOCTL_READ_REG))
+			sprintf(debugfs_buf, "IOCTL return value: %u\n",
+				pm_api_ret[1]);
+		if (!ret && pm_api_arg[1] == IOCTL_GET_QOS)
+			sprintf(debugfs_buf, "Default QoS: %u\nCurrent QoS: %u\n",
+				pm_api_ret[1], pm_api_ret[2]);
+		break;
+	case PM_CLOCK_ENABLE:
+		ret = zynqmp_pm_clock_enable(pm_api_arg[0]);
+		break;
+	case PM_CLOCK_DISABLE:
+		ret = zynqmp_pm_clock_disable(pm_api_arg[0]);
+		break;
+	case PM_CLOCK_GETSTATE:
+		ret = zynqmp_pm_clock_getstate(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf, "Clock state: %u\n",
+				pm_api_ret[0]);
+		break;
+	case PM_CLOCK_SETDIVIDER:
+		ret = zynqmp_pm_clock_setdivider(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_CLOCK_GETDIVIDER:
+		ret = zynqmp_pm_clock_getdivider(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf, "Divider Value: %d\n",
+				pm_api_ret[0]);
+		break;
+	case PM_CLOCK_SETPARENT:
+		ret = zynqmp_pm_clock_setparent(pm_api_arg[0], pm_api_arg[1]);
+		break;
+	case PM_CLOCK_GETPARENT:
+		ret = zynqmp_pm_clock_getparent(pm_api_arg[0], &pm_api_ret[0]);
+		if (!ret)
+			sprintf(debugfs_buf,
+				"Clock parent Index: %u\n", pm_api_ret[0]);
+		break;
+	case PM_QUERY_DATA:
+		qdata.qid = pm_api_arg[0];
+		qdata.arg1 = pm_api_arg[1];
+		qdata.arg2 = pm_api_arg[2];
+		qdata.arg3 = pm_api_arg[3];
+
+		ret = zynqmp_pm_query_data(qdata, pm_api_ret);
+		if (ret)
+			break;
+
+		switch (qdata.qid) {
+		case PM_QID_CLOCK_GET_NAME:
+			sprintf(debugfs_buf, "Clock name = %s\n",
+				(char *)pm_api_ret);
+			break;
+		case PM_QID_CLOCK_GET_FIXEDFACTOR_PARAMS:
+			sprintf(debugfs_buf, "Multiplier = %d, Divider = %d\n",
+				pm_api_ret[1], pm_api_ret[2]);
+			break;
+		default:
+			sprintf(debugfs_buf,
+				"data[0] = 0x%08x\ndata[1] = 0x%08x\n data[2] = 0x%08x\ndata[3] = 0x%08x\n",
+				pm_api_ret[0], pm_api_ret[1],
+				pm_api_ret[2], pm_api_ret[3]);
+		}
+		break;
+	default:
+		sprintf(debugfs_buf, "Unsupported PM-API request\n");
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * zynqmp_pm_debugfs_api_write() - debugfs write function
+ * @file:	User file
+ * @ptr:	User entered PM-API string
+ * @len:	Length of the userspace buffer
+ * @off:	Offset within the file
+ *
+ * Used for triggering pm api functions by writing
+ * echo <pm_api_id>	> /sys/kernel/debug/zynqmp_pm/power or
+ * echo <pm_api_name>	> /sys/kernel/debug/zynqmp_pm/power
+ *
+ * Return: Number of bytes copied if PM-API request succeeds,
+ *	   the corresponding error code otherwise
+ */
+static ssize_t zynqmp_pm_debugfs_api_write(struct file *file,
+					   const char __user *ptr, size_t len,
+					   loff_t *off)
+{
+	char *kern_buff, *tmp_buff;
+	char *pm_api_req;
+	u32 pm_id = 0;
+	u64 pm_api_arg[5] = {0, 0, 0, 0, 0};
+	/* Return values from PM APIs calls */
+	u32 pm_api_ret[4] = {0, 0, 0, 0};
+
+	int ret;
+	int i = 0;
+
+	strcpy(debugfs_buf, "");
+
+	if (*off != 0 || len <= 1 || len > PAGE_SIZE - 1)
+		return -EINVAL;
+
+	kern_buff = memdup_user_nul(ptr, len);
+	if (IS_ERR(kern_buff))
+		return PTR_ERR(kern_buff);
+	tmp_buff = kern_buff;
+
+	/* Read the API name from a user request */
+	pm_api_req = strsep(&kern_buff, " ");
+
+	ret = get_pm_api_id(pm_api_req, &pm_id);
+	if (ret < 0)
+		goto err;
+
+	/* Read node_id and arguments from the PM-API request */
+	pm_api_req = strsep(&kern_buff, " ");
+	while ((i < ARRAY_SIZE(pm_api_arg)) && pm_api_req) {
+		pm_api_arg[i++] = zynqmp_pm_argument_value(pm_api_req);
+		pm_api_req = strsep(&kern_buff, " ");
+	}
+
+	ret = process_api_request(pm_id, pm_api_arg, pm_api_ret);
+
+err:
+	kfree(tmp_buff);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+/**
+ * zynqmp_pm_debugfs_api_read() - debugfs read function
+ * @file:	User file
+ * @ptr:	Requested pm_api_version string
+ * @len:	Length of the userspace buffer
+ * @off:	Offset within the file
+ *
+ * Return: Length of the version string on success
+ *	   else error code
+ */
+static ssize_t zynqmp_pm_debugfs_api_read(struct file *file, char __user *ptr,
+					  size_t len, loff_t *off)
+{
+	return simple_read_from_buffer(ptr, len, off, debugfs_buf,
+				       strlen(debugfs_buf));
+}
+
+/* Setup debugfs fops */
+static const struct file_operations fops_zynqmp_pm_dbgfs = {
+	.owner = THIS_MODULE,
+	.write = zynqmp_pm_debugfs_api_write,
+	.read = zynqmp_pm_debugfs_api_read,
+};
+
+/**
+ * zynqmp_pm_api_debugfs_init - Initialize debugfs interface
+ *
+ * Return:	None
+ */
+void zynqmp_pm_api_debugfs_init(void)
+{
+	/* Initialize debugfs interface */
+	firmware_debugfs_root = debugfs_create_dir("zynqmp-firmware", NULL);
+	debugfs_create_file("pm", 0660, firmware_debugfs_root, NULL,
+			    &fops_zynqmp_pm_dbgfs);
+}
+
+/**
+ * zynqmp_pm_api_debugfs_exit - Remove debugfs interface
+ *
+ * Return:	None
+ */
+void zynqmp_pm_api_debugfs_exit(void)
+{
+	debugfs_remove_recursive(firmware_debugfs_root);
+}