From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration 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 Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- scripts/kconfig/util.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 scripts/kconfig/util.c (limited to 'scripts/kconfig/util.c') diff --git a/scripts/kconfig/util.c b/scripts/kconfig/util.c new file mode 100644 index 000000000..0809aa061 --- /dev/null +++ b/scripts/kconfig/util.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2002-2005 Roman Zippel + * Copyright (C) 2002-2005 Sam Ravnborg + */ + +#include +#include +#include + +#include +#include +#include +#include "lkc.h" + +/* hash table of all parsed Kconfig files */ +static HASHTABLE_DEFINE(file_hashtable, 1U << 11); + +struct file { + struct hlist_node node; + struct { + const char *name; + int lineno; + } parent; + char name[]; +}; + +static void die_duplicated_include(struct file *file, + const char *parent, int lineno) +{ + fprintf(stderr, + "%s:%d: error: repeated inclusion of %s\n" + "%s:%d: note: location of first inclusion of %s\n", + parent, lineno, file->name, + file->parent.name, file->parent.lineno, file->name); + exit(1); +} + +/* file already present in list? If not add it */ +const char *file_lookup(const char *name, + const char *parent_name, int parent_lineno) +{ + const char *parent = NULL; + struct file *file; + size_t len; + int hash = hash_str(name); + + if (parent_name) + parent = file_lookup(parent_name, NULL, 0); + + hash_for_each_possible(file_hashtable, file, node, hash) + if (!strcmp(name, file->name)) { + if (!parent_name) + return file->name; + die_duplicated_include(file, parent, parent_lineno); + } + + len = strlen(name); + file = xmalloc(sizeof(*file) + len + 1); + memset(file, 0, sizeof(*file)); + memcpy(file->name, name, len); + file->name[len] = '\0'; + file->parent.name = parent; + file->parent.lineno = parent_lineno; + + hash_add(file_hashtable, &file->node, hash); + + str_printf(&autoconf_cmd, "\t%s \\\n", name); + + return file->name; +} + +/* Allocate initial growable string */ +struct gstr str_new(void) +{ + struct gstr gs; + gs.s = xmalloc(sizeof(char) * 64); + gs.len = 64; + gs.max_width = 0; + strcpy(gs.s, "\0"); + return gs; +} + +/* Free storage for growable string */ +void str_free(struct gstr *gs) +{ + free(gs->s); + gs->s = NULL; + gs->len = 0; +} + +/* Append to growable string */ +void str_append(struct gstr *gs, const char *s) +{ + size_t l; + if (s) { + l = strlen(gs->s) + strlen(s) + 1; + if (l > gs->len) { + gs->s = xrealloc(gs->s, l); + gs->len = l; + } + strcat(gs->s, s); + } +} + +/* Append printf formatted string to growable string */ +void str_printf(struct gstr *gs, const char *fmt, ...) +{ + va_list ap; + char s[10000]; /* big enough... */ + va_start(ap, fmt); + vsnprintf(s, sizeof(s), fmt, ap); + str_append(gs, s); + va_end(ap); +} + +/* Retrieve value of growable string */ +char *str_get(const struct gstr *gs) +{ + return gs->s; +} -- cgit v1.3.1