KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

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 <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 106 insertions, 0 deletions

diff --git a/include/crypto/engine.h b/include/crypto/engine.h
new file mode 100644
index 000000000..2e6034443
--- /dev/null
+++ b/include/crypto/engine.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Crypto engine API
+ *
+ * Copyright (c) 2016 Baolin Wang <baolin.wang@linaro.org>
+ */
+#ifndef _CRYPTO_ENGINE_H
+#define _CRYPTO_ENGINE_H
+
+#include <crypto/aead.h>
+#include <crypto/akcipher.h>
+#include <crypto/hash.h>
+#include <crypto/kpp.h>
+#include <crypto/skcipher.h>
+#include <linux/types.h>
+
+struct crypto_engine;
+struct device;
+
+/*
+ * struct crypto_engine_op - crypto hardware engine operations
+ * @do_one_request: do encryption for current request
+ */
+struct crypto_engine_op {
+	int (*do_one_request)(struct crypto_engine *engine,
+			      void *areq);
+};
+
+struct aead_engine_alg {
+	struct aead_alg base;
+	struct crypto_engine_op op;
+};
+
+struct ahash_engine_alg {
+	struct ahash_alg base;
+	struct crypto_engine_op op;
+};
+
+struct akcipher_engine_alg {
+	struct akcipher_alg base;
+	struct crypto_engine_op op;
+};
+
+struct kpp_engine_alg {
+	struct kpp_alg base;
+	struct crypto_engine_op op;
+};
+
+struct skcipher_engine_alg {
+	struct skcipher_alg base;
+	struct crypto_engine_op op;
+};
+
+int crypto_transfer_aead_request_to_engine(struct crypto_engine *engine,
+					   struct aead_request *req);
+int crypto_transfer_akcipher_request_to_engine(struct crypto_engine *engine,
+					       struct akcipher_request *req);
+int crypto_transfer_hash_request_to_engine(struct crypto_engine *engine,
+					       struct ahash_request *req);
+int crypto_transfer_kpp_request_to_engine(struct crypto_engine *engine,
+					  struct kpp_request *req);
+int crypto_transfer_skcipher_request_to_engine(struct crypto_engine *engine,
+					       struct skcipher_request *req);
+void crypto_finalize_aead_request(struct crypto_engine *engine,
+				  struct aead_request *req, int err);
+void crypto_finalize_akcipher_request(struct crypto_engine *engine,
+				      struct akcipher_request *req, int err);
+void crypto_finalize_hash_request(struct crypto_engine *engine,
+				  struct ahash_request *req, int err);
+void crypto_finalize_kpp_request(struct crypto_engine *engine,
+				 struct kpp_request *req, int err);
+void crypto_finalize_skcipher_request(struct crypto_engine *engine,
+				      struct skcipher_request *req, int err);
+int crypto_engine_start(struct crypto_engine *engine);
+int crypto_engine_stop(struct crypto_engine *engine);
+struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt);
+struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
+						       bool retry_support,
+						       bool rt, int qlen);
+void crypto_engine_exit(struct crypto_engine *engine);
+
+int crypto_engine_register_aead(struct aead_engine_alg *alg);
+void crypto_engine_unregister_aead(struct aead_engine_alg *alg);
+int crypto_engine_register_aeads(struct aead_engine_alg *algs, int count);
+void crypto_engine_unregister_aeads(struct aead_engine_alg *algs, int count);
+
+int crypto_engine_register_ahash(struct ahash_engine_alg *alg);
+void crypto_engine_unregister_ahash(struct ahash_engine_alg *alg);
+int crypto_engine_register_ahashes(struct ahash_engine_alg *algs, int count);
+void crypto_engine_unregister_ahashes(struct ahash_engine_alg *algs,
+				      int count);
+
+int crypto_engine_register_akcipher(struct akcipher_engine_alg *alg);
+void crypto_engine_unregister_akcipher(struct akcipher_engine_alg *alg);
+
+int crypto_engine_register_kpp(struct kpp_engine_alg *alg);
+void crypto_engine_unregister_kpp(struct kpp_engine_alg *alg);
+
+int crypto_engine_register_skcipher(struct skcipher_engine_alg *alg);
+void crypto_engine_unregister_skcipher(struct skcipher_engine_alg *alg);
+int crypto_engine_register_skciphers(struct skcipher_engine_alg *algs,
+				     int count);
+void crypto_engine_unregister_skciphers(struct skcipher_engine_alg *algs,
+					int count);
+
+#endif /* _CRYPTO_ENGINE_H */