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, 18 insertions, 0 deletions

diff --git a/Documentation/crypto/api-sig.rst b/Documentation/crypto/api-sig.rst
new file mode 100644
index 000000000..4d8aba8ae
--- /dev/null
+++ b/Documentation/crypto/api-sig.rst
@@ -0,0 +1,18 @@
+Asymmetric Signature
+====================
+
+Asymmetric Signature Algorithm Definitions
+------------------------------------------
+
+.. kernel-doc:: include/crypto/sig.h
+   :functions: sig_alg
+
+Asymmetric Signature API
+------------------------
+
+.. kernel-doc:: include/crypto/sig.h
+   :doc: Generic Public Key Signature API
+
+.. kernel-doc:: include/crypto/sig.h
+   :functions: crypto_alloc_sig crypto_free_sig crypto_sig_set_pubkey crypto_sig_set_privkey crypto_sig_keysize crypto_sig_maxsize crypto_sig_digestsize crypto_sig_sign crypto_sig_verify
+