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, 34 insertions, 0 deletions

diff --git a/include/crypto/authenc.h b/include/crypto/authenc.h
new file mode 100644
index 000000000..15a9caa23
--- /dev/null
+++ b/include/crypto/authenc.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Authenc: Simple AEAD wrapper for IPsec
+ *
+ * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+#ifndef _CRYPTO_AUTHENC_H
+#define _CRYPTO_AUTHENC_H
+
+#include <linux/types.h>
+
+enum {
+	CRYPTO_AUTHENC_KEYA_UNSPEC,
+	CRYPTO_AUTHENC_KEYA_PARAM,
+};
+
+struct crypto_authenc_key_param {
+	__be32 enckeylen;
+};
+
+struct crypto_authenc_keys {
+	const u8 *authkey;
+	const u8 *enckey;
+
+	unsigned int authkeylen;
+	unsigned int enckeylen;
+};
+
+int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
+			       unsigned int keylen);
+int crypto_krb5enc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
+			       unsigned int keylen);
+
+#endif	/* _CRYPTO_AUTHENC_H */