KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
new file mode 100644
index 000000000..a6c2897bc
--- /dev/null
+++ b/include/keys/system_keyring.h
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* System keyring containing trusted public keys.
+ *
+ * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _KEYS_SYSTEM_KEYRING_H
+#define _KEYS_SYSTEM_KEYRING_H
+
+#include <linux/key.h>
+
+enum blacklist_hash_type {
+	/* TBSCertificate hash */
+	BLACKLIST_HASH_X509_TBS = 1,
+	/* Raw data hash */
+	BLACKLIST_HASH_BINARY = 2,
+};
+
+#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING
+
+extern int restrict_link_by_builtin_trusted(struct key *keyring,
+					    const struct key_type *type,
+					    const union key_payload *payload,
+					    struct key *restriction_key);
+int restrict_link_by_digsig_builtin(struct key *dest_keyring,
+				    const struct key_type *type,
+				    const union key_payload *payload,
+				    struct key *restriction_key);
+extern __init int load_module_cert(struct key *keyring);
+
+#else
+#define restrict_link_by_builtin_trusted restrict_link_reject
+#define restrict_link_by_digsig_builtin restrict_link_reject
+
+static inline __init int load_module_cert(struct key *keyring)
+{
+	return 0;
+}
+
+#endif
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+extern int restrict_link_by_builtin_and_secondary_trusted(
+	struct key *keyring,
+	const struct key_type *type,
+	const union key_payload *payload,
+	struct key *restriction_key);
+int restrict_link_by_digsig_builtin_and_secondary(struct key *keyring,
+						  const struct key_type *type,
+						  const union key_payload *payload,
+						  struct key *restriction_key);
+void __init add_to_secondary_keyring(const char *source, const void *data, size_t len);
+#else
+#define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted
+#define restrict_link_by_digsig_builtin_and_secondary restrict_link_by_digsig_builtin
+static inline void __init add_to_secondary_keyring(const char *source, const void *data, size_t len)
+{
+}
+#endif
+
+#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
+extern int restrict_link_by_builtin_secondary_and_machine(
+	struct key *dest_keyring,
+	const struct key_type *type,
+	const union key_payload *payload,
+	struct key *restrict_key);
+extern void __init set_machine_trusted_keys(struct key *keyring);
+#else
+#define restrict_link_by_builtin_secondary_and_machine restrict_link_by_builtin_trusted
+static inline void __init set_machine_trusted_keys(struct key *keyring)
+{
+}
+#endif
+
+#ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING
+extern int mark_hash_blacklisted(const u8 *hash, size_t hash_len,
+			       enum blacklist_hash_type hash_type);
+extern int is_hash_blacklisted(const u8 *hash, size_t hash_len,
+			       enum blacklist_hash_type hash_type);
+extern int is_binary_blacklisted(const u8 *hash, size_t hash_len);
+#else
+static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len,
+				      enum blacklist_hash_type hash_type)
+{
+	return 0;
+}
+
+static inline int is_binary_blacklisted(const u8 *hash, size_t hash_len)
+{
+	return 0;
+}
+#endif
+
+struct pkcs7_message;
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+extern int add_key_to_revocation_list(const char *data, size_t size);
+extern int is_key_on_revocation_list(struct pkcs7_message *pkcs7);
+#else
+static inline int add_key_to_revocation_list(const char *data, size_t size)
+{
+	return 0;
+}
+static inline int is_key_on_revocation_list(struct pkcs7_message *pkcs7)
+{
+	return -ENOKEY;
+}
+#endif
+
+#ifdef CONFIG_IMA_BLACKLIST_KEYRING
+extern struct key *ima_blacklist_keyring;
+
+static inline struct key *get_ima_blacklist_keyring(void)
+{
+	return ima_blacklist_keyring;
+}
+#else
+static inline struct key *get_ima_blacklist_keyring(void)
+{
+	return NULL;
+}
+#endif /* CONFIG_IMA_BLACKLIST_KEYRING */
+
+#if defined(CONFIG_INTEGRITY_PLATFORM_KEYRING) && \
+	defined(CONFIG_SYSTEM_TRUSTED_KEYRING)
+extern void __init set_platform_trusted_keys(struct key *keyring);
+#else
+static inline void set_platform_trusted_keys(struct key *keyring)
+{
+}
+#endif
+
+#endif /* _KEYS_SYSTEM_KEYRING_H */