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, 26 insertions, 0 deletions

diff --git a/Documentation/crypto/api-aead.rst b/Documentation/crypto/api-aead.rst
new file mode 100644
index 000000000..78d073319
--- /dev/null
+++ b/Documentation/crypto/api-aead.rst
@@ -0,0 +1,26 @@
+Authenticated Encryption With Associated Data (AEAD)
+====================================================
+
+Authenticated Encryption With Associated Data (AEAD) Algorithm Definitions
+--------------------------------------------------------------------------
+
+.. kernel-doc:: include/crypto/aead.h
+   :doc: Authenticated Encryption With Associated Data (AEAD) Cipher API
+
+.. kernel-doc:: include/crypto/aead.h
+   :functions: aead_request aead_alg
+
+Authenticated Encryption With Associated Data (AEAD) Cipher API
+---------------------------------------------------------------
+
+.. kernel-doc:: include/crypto/aead.h
+   :functions: crypto_alloc_aead crypto_free_aead crypto_aead_ivsize crypto_aead_authsize crypto_aead_blocksize crypto_aead_setkey crypto_aead_setauthsize crypto_aead_encrypt crypto_aead_decrypt
+
+Asynchronous AEAD Request Handle
+--------------------------------
+
+.. kernel-doc:: include/crypto/aead.h
+   :doc: Asynchronous AEAD Request Handle
+
+.. kernel-doc:: include/crypto/aead.h
+   :functions: crypto_aead_reqsize aead_request_set_tfm aead_request_alloc aead_request_free aead_request_set_callback aead_request_set_crypt aead_request_set_ad