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, 56 insertions, 0 deletions

diff --git a/Documentation/input/devices/pxrc.rst b/Documentation/input/devices/pxrc.rst
new file mode 100644
index 000000000..5a86df4ad
--- /dev/null
+++ b/Documentation/input/devices/pxrc.rst
@@ -0,0 +1,56 @@
+=======================================================
+pxrc - PhoenixRC Flight Controller Adapter
+=======================================================
+
+:Author: Marcus Folkesson <marcus.folkesson@gmail.com>
+
+This driver let you use your own RC controller plugged into the
+adapter that comes with PhoenixRC or other compatible adapters.
+
+The adapter supports 7 analog channels and 1 digital input switch.
+
+Notes
+=====
+
+Many RC controllers is able to configure which stick goes to which channel.
+This is also configurable in most simulators, so a matching is not necessary.
+
+The driver is generating the following input event for analog channels:
+
++---------+----------------+
+| Channel |      Event     |
++=========+================+
+|     1   |  ABS_X         |
++---------+----------------+
+|     2   |  ABS_Y         |
++---------+----------------+
+|     3   |  ABS_RX        |
++---------+----------------+
+|     4   |  ABS_RY        |
++---------+----------------+
+|     5   |  ABS_RUDDER    |
++---------+----------------+
+|     6   |  ABS_THROTTLE  |
++---------+----------------+
+|     7   |  ABS_MISC      |
++---------+----------------+
+
+The digital input switch is generated as an `BTN_A` event.
+
+Manual Testing
+==============
+
+To test this driver's functionality you may use `input-event` which is part of
+the `input layer utilities` suite [1]_.
+
+For example::
+
+    > modprobe pxrc
+    > input-events <devnr>
+
+To print all input events from input `devnr`.
+
+References
+==========
+
+.. [1] https://www.kraxel.org/cgit/input/