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, 155 insertions, 0 deletions

diff --git a/include/crypto/internal/akcipher.h b/include/crypto/internal/akcipher.h
new file mode 100644
index 000000000..14ee62bc5
--- /dev/null
+++ b/include/crypto/internal/akcipher.h
@@ -0,0 +1,155 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Public Key Encryption
+ *
+ * Copyright (c) 2015, Intel Corporation
+ * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
+ */
+#ifndef _CRYPTO_AKCIPHER_INT_H
+#define _CRYPTO_AKCIPHER_INT_H
+#include <crypto/akcipher.h>
+#include <crypto/algapi.h>
+
+struct akcipher_instance {
+	void (*free)(struct akcipher_instance *inst);
+	union {
+		struct {
+			char head[offsetof(struct akcipher_alg, base)];
+			struct crypto_instance base;
+		} s;
+		struct akcipher_alg alg;
+	};
+};
+
+struct crypto_akcipher_spawn {
+	struct crypto_spawn base;
+};
+
+/*
+ * Transform internal helpers.
+ */
+static inline void *akcipher_request_ctx(struct akcipher_request *req)
+{
+	return req->__ctx;
+}
+
+static inline void *akcipher_request_ctx_dma(struct akcipher_request *req)
+{
+	unsigned int align = crypto_dma_align();
+
+	if (align <= crypto_tfm_ctx_alignment())
+		align = 1;
+
+	return PTR_ALIGN(akcipher_request_ctx(req), align);
+}
+
+static inline void akcipher_set_reqsize(struct crypto_akcipher *akcipher,
+					unsigned int reqsize)
+{
+	akcipher->reqsize = reqsize;
+}
+
+static inline void akcipher_set_reqsize_dma(struct crypto_akcipher *akcipher,
+					    unsigned int reqsize)
+{
+	reqsize += crypto_dma_align() & ~(crypto_tfm_ctx_alignment() - 1);
+	akcipher->reqsize = reqsize;
+}
+
+static inline void *akcipher_tfm_ctx(struct crypto_akcipher *tfm)
+{
+	return crypto_tfm_ctx(&tfm->base);
+}
+
+static inline void *akcipher_tfm_ctx_dma(struct crypto_akcipher *tfm)
+{
+	return crypto_tfm_ctx_dma(&tfm->base);
+}
+
+static inline void akcipher_request_complete(struct akcipher_request *req,
+					     int err)
+{
+	crypto_request_complete(&req->base, err);
+}
+
+static inline const char *akcipher_alg_name(struct crypto_akcipher *tfm)
+{
+	return crypto_akcipher_tfm(tfm)->__crt_alg->cra_name;
+}
+
+static inline struct crypto_instance *akcipher_crypto_instance(
+		struct akcipher_instance *inst)
+{
+	return container_of(&inst->alg.base, struct crypto_instance, alg);
+}
+
+static inline struct akcipher_instance *akcipher_instance(
+		struct crypto_instance *inst)
+{
+	return container_of(&inst->alg, struct akcipher_instance, alg.base);
+}
+
+static inline struct akcipher_instance *akcipher_alg_instance(
+		struct crypto_akcipher *akcipher)
+{
+	return akcipher_instance(crypto_tfm_alg_instance(&akcipher->base));
+}
+
+static inline void *akcipher_instance_ctx(struct akcipher_instance *inst)
+{
+	return crypto_instance_ctx(akcipher_crypto_instance(inst));
+}
+
+int crypto_grab_akcipher(struct crypto_akcipher_spawn *spawn,
+			 struct crypto_instance *inst,
+			 const char *name, u32 type, u32 mask);
+
+static inline struct crypto_akcipher *crypto_spawn_akcipher(
+		struct crypto_akcipher_spawn *spawn)
+{
+	return crypto_spawn_tfm2(&spawn->base);
+}
+
+static inline void crypto_drop_akcipher(struct crypto_akcipher_spawn *spawn)
+{
+	crypto_drop_spawn(&spawn->base);
+}
+
+static inline struct akcipher_alg *crypto_spawn_akcipher_alg(
+		struct crypto_akcipher_spawn *spawn)
+{
+	return container_of(spawn->base.alg, struct akcipher_alg, base);
+}
+
+/**
+ * crypto_register_akcipher() -- Register public key algorithm
+ *
+ * Function registers an implementation of a public key cipher algorithm
+ *
+ * @alg:	algorithm definition
+ *
+ * Return: zero on success; error code in case of error
+ */
+int crypto_register_akcipher(struct akcipher_alg *alg);
+
+/**
+ * crypto_unregister_akcipher() -- Unregister public key algorithm
+ *
+ * Function unregisters an implementation of a public key cipher algorithm
+ *
+ * @alg:	algorithm definition
+ */
+void crypto_unregister_akcipher(struct akcipher_alg *alg);
+
+/**
+ * akcipher_register_instance() -- Unregister public key template instance
+ *
+ * Function registers an implementation of an asymmetric key algorithm
+ * created from a template
+ *
+ * @tmpl:	the template from which the algorithm was created
+ * @inst:	the template instance
+ */
+int akcipher_register_instance(struct crypto_template *tmpl,
+		struct akcipher_instance *inst);
+#endif