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, 48 insertions, 0 deletions

diff --git a/include/crypto/sm4.h b/include/crypto/sm4.h
new file mode 100644
index 000000000..9656a9a40
--- /dev/null
+++ b/include/crypto/sm4.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Common values for the SM4 algorithm
+ * Copyright (C) 2018 ARM Limited or its affiliates.
+ * Copyright (c) 2021 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
+ */
+
+#ifndef _CRYPTO_SM4_H
+#define _CRYPTO_SM4_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+#define SM4_KEY_SIZE	16
+#define SM4_BLOCK_SIZE	16
+#define SM4_RKEY_WORDS	32
+
+struct sm4_ctx {
+	u32 rkey_enc[SM4_RKEY_WORDS];
+	u32 rkey_dec[SM4_RKEY_WORDS];
+};
+
+extern const u32 crypto_sm4_fk[];
+extern const u32 crypto_sm4_ck[];
+extern const u8 crypto_sm4_sbox[];
+
+/**
+ * sm4_expandkey - Expands the SM4 key as described in GB/T 32907-2016
+ * @ctx:	The location where the computed key will be stored.
+ * @in_key:	The supplied key.
+ * @key_len:	The length of the supplied key.
+ *
+ * Returns 0 on success. The function fails only if an invalid key size (or
+ * pointer) is supplied.
+ */
+int sm4_expandkey(struct sm4_ctx *ctx, const u8 *in_key,
+			  unsigned int key_len);
+
+/**
+ * sm4_crypt_block - Encrypt or decrypt a single SM4 block
+ * @rk:		The rkey_enc for encrypt or rkey_dec for decrypt
+ * @out:	Buffer to store output data
+ * @in: 	Buffer containing the input data
+ */
+void sm4_crypt_block(const u32 *rk, u8 *out, const u8 *in);
+
+#endif