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, 621 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/utdebug.c b/drivers/acpi/acpica/utdebug.c
new file mode 100644
index 000000000..a31e07400
--- /dev/null
+++ b/drivers/acpi/acpica/utdebug.c
@@ -0,0 +1,621 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: utdebug - Debug print/trace routines
+ *
+ * Copyright (C) 2000 - 2026, Intel Corp.
+ *
+ *****************************************************************************/
+
+#define EXPORT_ACPI_INTERFACES
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acinterp.h"
+
+#define _COMPONENT          ACPI_UTILITIES
+ACPI_MODULE_NAME("utdebug")
+
+#ifdef ACPI_DEBUG_OUTPUT
+static acpi_thread_id acpi_gbl_previous_thread_id = (acpi_thread_id) 0xFFFFFFFF;
+static const char *acpi_gbl_function_entry_prefix = "----Entry";
+static const char *acpi_gbl_function_exit_prefix = "----Exit-";
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_init_stack_ptr_trace
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Save the current CPU stack pointer at subsystem startup
+ *
+ ******************************************************************************/
+
+void acpi_ut_init_stack_ptr_trace(void)
+{
+	acpi_size current_sp;
+
+#pragma GCC diagnostic push
+#if defined(__GNUC__) && __GNUC__ >= 12
+#pragma GCC diagnostic ignored "-Wdangling-pointer="
+#endif
+	acpi_gbl_entry_stack_pointer = &current_sp;
+#pragma GCC diagnostic pop
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_track_stack_ptr
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Save the current CPU stack pointer
+ *
+ ******************************************************************************/
+
+void acpi_ut_track_stack_ptr(void)
+{
+	acpi_size current_sp;
+
+	if (&current_sp < acpi_gbl_lowest_stack_pointer) {
+#pragma GCC diagnostic push
+#if defined(__GNUC__) && __GNUC__ >= 12
+#pragma GCC diagnostic ignored "-Wdangling-pointer="
+#endif
+		acpi_gbl_lowest_stack_pointer = &current_sp;
+#pragma GCC diagnostic pop
+	}
+
+	if (acpi_gbl_nesting_level > acpi_gbl_deepest_nesting) {
+		acpi_gbl_deepest_nesting = acpi_gbl_nesting_level;
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_trim_function_name
+ *
+ * PARAMETERS:  function_name       - Ascii string containing a procedure name
+ *
+ * RETURN:      Updated pointer to the function name
+ *
+ * DESCRIPTION: Remove the "Acpi" prefix from the function name, if present.
+ *              This allows compiler macros such as __func__ to be used
+ *              with no change to the debug output.
+ *
+ ******************************************************************************/
+
+static const char *acpi_ut_trim_function_name(const char *function_name)
+{
+
+	/* All Function names are longer than 4 chars, check is safe */
+
+	if (*(ACPI_CAST_PTR(u32, function_name)) == ACPI_PREFIX_MIXED) {
+
+		/* This is the case where the original source has not been modified */
+
+		return (function_name + 4);
+	}
+
+	if (*(ACPI_CAST_PTR(u32, function_name)) == ACPI_PREFIX_LOWER) {
+
+		/* This is the case where the source has been 'linuxized' */
+
+		return (function_name + 5);
+	}
+
+	return (function_name);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_debug_print
+ *
+ * PARAMETERS:  requested_debug_level - Requested debug print level
+ *              line_number         - Caller's line number (for error output)
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              format              - Printf format field
+ *              ...                 - Optional printf arguments
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Print error message with prefix consisting of the module name,
+ *              line number, and component ID.
+ *
+ ******************************************************************************/
+
+void ACPI_INTERNAL_VAR_XFACE
+acpi_debug_print(u32 requested_debug_level,
+		 u32 line_number,
+		 const char *function_name,
+		 const char *module_name,
+		 u32 component_id, const char *format, ...)
+{
+	acpi_thread_id thread_id;
+	va_list args;
+#ifdef ACPI_APPLICATION
+	int fill_count;
+#endif
+
+	/* Check if debug output enabled */
+
+	if (!ACPI_IS_DEBUG_ENABLED(requested_debug_level, component_id)) {
+		return;
+	}
+
+	/*
+	 * Thread tracking and context switch notification
+	 */
+	thread_id = acpi_os_get_thread_id();
+	if (thread_id != acpi_gbl_previous_thread_id) {
+		if (ACPI_LV_THREADS & acpi_dbg_level) {
+			acpi_os_printf
+			    ("\n**** Context Switch from TID %u to TID %u ****\n\n",
+			     (u32)acpi_gbl_previous_thread_id, (u32)thread_id);
+		}
+
+		acpi_gbl_previous_thread_id = thread_id;
+		acpi_gbl_nesting_level = 0;
+	}
+
+	/*
+	 * Display the module name, current line number, thread ID (if requested),
+	 * current procedure nesting level, and the current procedure name
+	 */
+	acpi_os_printf("%9s-%04d ", module_name, line_number);
+
+#ifdef ACPI_APPLICATION
+	/*
+	 * For acpi_exec/iASL only, emit the thread ID and nesting level.
+	 * Note: nesting level is really only useful during a single-thread
+	 * execution. Otherwise, multiple threads will keep resetting the
+	 * level.
+	 */
+	if (ACPI_LV_THREADS & acpi_dbg_level) {
+		acpi_os_printf("[%u] ", (u32)thread_id);
+	}
+
+	fill_count = 48 - acpi_gbl_nesting_level -
+	    strlen(acpi_ut_trim_function_name(function_name));
+	if (fill_count < 0) {
+		fill_count = 0;
+	}
+
+	acpi_os_printf("[%02d] %*s",
+		       acpi_gbl_nesting_level, acpi_gbl_nesting_level + 1, " ");
+	acpi_os_printf("%s%*s: ",
+		       acpi_ut_trim_function_name(function_name), fill_count,
+		       " ");
+
+#else
+	acpi_os_printf("%-22.22s: ", acpi_ut_trim_function_name(function_name));
+#endif
+
+	va_start(args, format);
+	acpi_os_vprintf(format, args);
+	va_end(args);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_debug_print)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_debug_print_raw
+ *
+ * PARAMETERS:  requested_debug_level - Requested debug print level
+ *              line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              format              - Printf format field
+ *              ...                 - Optional printf arguments
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Print message with no headers. Has same interface as
+ *              debug_print so that the same macros can be used.
+ *
+ ******************************************************************************/
+void ACPI_INTERNAL_VAR_XFACE
+acpi_debug_print_raw(u32 requested_debug_level,
+		     u32 line_number,
+		     const char *function_name,
+		     const char *module_name,
+		     u32 component_id, const char *format, ...)
+{
+	va_list args;
+
+	/* Check if debug output enabled */
+
+	if (!ACPI_IS_DEBUG_ENABLED(requested_debug_level, component_id)) {
+		return;
+	}
+
+	va_start(args, format);
+	acpi_os_vprintf(format, args);
+	va_end(args);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_debug_print_raw)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_trace
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function entry trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level
+ *
+ ******************************************************************************/
+void
+acpi_ut_trace(u32 line_number,
+	      const char *function_name,
+	      const char *module_name, u32 component_id)
+{
+
+	acpi_gbl_nesting_level++;
+	acpi_ut_track_stack_ptr();
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s\n",
+				 acpi_gbl_function_entry_prefix);
+	}
+}
+
+ACPI_EXPORT_SYMBOL(acpi_ut_trace)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_trace_ptr
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              pointer             - Pointer to display
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function entry trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level
+ *
+ ******************************************************************************/
+void
+acpi_ut_trace_ptr(u32 line_number,
+		  const char *function_name,
+		  const char *module_name,
+		  u32 component_id, const void *pointer)
+{
+
+	acpi_gbl_nesting_level++;
+	acpi_ut_track_stack_ptr();
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s %p\n",
+				 acpi_gbl_function_entry_prefix, pointer);
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_trace_str
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              string              - Additional string to display
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function entry trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level
+ *
+ ******************************************************************************/
+
+void
+acpi_ut_trace_str(u32 line_number,
+		  const char *function_name,
+		  const char *module_name, u32 component_id, const char *string)
+{
+
+	acpi_gbl_nesting_level++;
+	acpi_ut_track_stack_ptr();
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s %s\n",
+				 acpi_gbl_function_entry_prefix, string);
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_trace_u32
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              integer             - Integer to display
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function entry trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level
+ *
+ ******************************************************************************/
+
+void
+acpi_ut_trace_u32(u32 line_number,
+		  const char *function_name,
+		  const char *module_name, u32 component_id, u32 integer)
+{
+
+	acpi_gbl_nesting_level++;
+	acpi_ut_track_stack_ptr();
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s %08X\n",
+				 acpi_gbl_function_entry_prefix, integer);
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_exit
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function exit trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level
+ *
+ ******************************************************************************/
+
+void
+acpi_ut_exit(u32 line_number,
+	     const char *function_name,
+	     const char *module_name, u32 component_id)
+{
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s\n",
+				 acpi_gbl_function_exit_prefix);
+	}
+
+	if (acpi_gbl_nesting_level) {
+		acpi_gbl_nesting_level--;
+	}
+}
+
+ACPI_EXPORT_SYMBOL(acpi_ut_exit)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_status_exit
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              status              - Exit status code
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function exit trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level. Prints exit status also.
+ *
+ ******************************************************************************/
+void
+acpi_ut_status_exit(u32 line_number,
+		    const char *function_name,
+		    const char *module_name,
+		    u32 component_id, acpi_status status)
+{
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		if (ACPI_SUCCESS(status)) {
+			acpi_debug_print(ACPI_LV_FUNCTIONS,
+					 line_number, function_name,
+					 module_name, component_id, "%s %s\n",
+					 acpi_gbl_function_exit_prefix,
+					 acpi_format_exception(status));
+		} else {
+			acpi_debug_print(ACPI_LV_FUNCTIONS,
+					 line_number, function_name,
+					 module_name, component_id,
+					 "%s ****Exception****: %s\n",
+					 acpi_gbl_function_exit_prefix,
+					 acpi_format_exception(status));
+		}
+	}
+
+	if (acpi_gbl_nesting_level) {
+		acpi_gbl_nesting_level--;
+	}
+}
+
+ACPI_EXPORT_SYMBOL(acpi_ut_status_exit)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_value_exit
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              value               - Value to be printed with exit msg
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function exit trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level. Prints exit value also.
+ *
+ ******************************************************************************/
+void
+acpi_ut_value_exit(u32 line_number,
+		   const char *function_name,
+		   const char *module_name, u32 component_id, u64 value)
+{
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s %8.8X%8.8X\n",
+				 acpi_gbl_function_exit_prefix,
+				 ACPI_FORMAT_UINT64(value));
+	}
+
+	if (acpi_gbl_nesting_level) {
+		acpi_gbl_nesting_level--;
+	}
+}
+
+ACPI_EXPORT_SYMBOL(acpi_ut_value_exit)
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_ptr_exit
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              ptr                 - Pointer to display
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function exit trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level. Prints exit value also.
+ *
+ ******************************************************************************/
+void
+acpi_ut_ptr_exit(u32 line_number,
+		 const char *function_name,
+		 const char *module_name, u32 component_id, u8 *ptr)
+{
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s %p\n",
+				 acpi_gbl_function_exit_prefix, ptr);
+	}
+
+	if (acpi_gbl_nesting_level) {
+		acpi_gbl_nesting_level--;
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_str_exit
+ *
+ * PARAMETERS:  line_number         - Caller's line number
+ *              function_name       - Caller's procedure name
+ *              module_name         - Caller's module name
+ *              component_id        - Caller's component ID
+ *              string              - String to display
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Function exit trace. Prints only if TRACE_FUNCTIONS bit is
+ *              set in debug_level. Prints exit value also.
+ *
+ ******************************************************************************/
+
+void
+acpi_ut_str_exit(u32 line_number,
+		 const char *function_name,
+		 const char *module_name, u32 component_id, const char *string)
+{
+
+	/* Check if enabled up-front for performance */
+
+	if (ACPI_IS_DEBUG_ENABLED(ACPI_LV_FUNCTIONS, component_id)) {
+		acpi_debug_print(ACPI_LV_FUNCTIONS,
+				 line_number, function_name, module_name,
+				 component_id, "%s %s\n",
+				 acpi_gbl_function_exit_prefix, string);
+	}
+
+	if (acpi_gbl_nesting_level) {
+		acpi_gbl_nesting_level--;
+	}
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_trace_point
+ *
+ * PARAMETERS:  type                - Trace event type
+ *              begin               - TRUE if before execution
+ *              aml                 - Executed AML address
+ *              pathname            - Object path
+ *              pointer             - Pointer to the related object
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Interpreter execution trace.
+ *
+ ******************************************************************************/
+
+void
+acpi_trace_point(acpi_trace_event_type type, u8 begin, u8 *aml, char *pathname)
+{
+
+	ACPI_FUNCTION_ENTRY();
+
+	acpi_ex_trace_point(type, begin, aml, pathname);
+
+#ifdef ACPI_USE_SYSTEM_TRACER
+	acpi_os_trace_point(type, begin, aml, pathname);
+#endif
+}
+
+ACPI_EXPORT_SYMBOL(acpi_trace_point)
+
+#endif