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, 30 insertions, 0 deletions

diff --git a/Documentation/maintainer/configure-git.rst b/Documentation/maintainer/configure-git.rst
new file mode 100644
index 000000000..0c21f203c
--- /dev/null
+++ b/Documentation/maintainer/configure-git.rst
@@ -0,0 +1,30 @@
+Configuring Git
+===============
+
+This chapter describes maintainer level git configuration.
+
+Tagged branches used in pull requests (see
+Documentation/maintainer/pull-requests.rst) should be signed with the
+developers public GPG key. Signed tags can be created by passing
+``-u <key-id>`` to ``git tag``. However, since you would *usually* use the same
+key for the project, you can set it in the configuration and use the ``-s``
+flag. To set the default ``key-id`` use::
+
+	git config user.signingkey "keyname"
+
+Alternatively, edit your ``.git/config`` or ``~/.gitconfig`` file by hand::
+
+	[user]
+		name = Jane Developer
+		email = jd@domain.org
+		signingkey = jd@domain.org
+
+You may need to tell ``git`` to use ``gpg2``::
+
+	[gpg]
+		program = /path/to/gpg2
+
+You may also like to tell ``gpg`` which ``tty`` to use (add to your shell
+rc file)::
+
+	export GPG_TTY=$(tty)