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, 29 insertions, 0 deletions

diff --git a/drivers/usb/image/Kconfig b/drivers/usb/image/Kconfig
new file mode 100644
index 000000000..a65c638e7
--- /dev/null
+++ b/drivers/usb/image/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB Imaging devices configuration
+#
+comment "USB Imaging devices"
+
+config USB_MDC800
+	tristate "USB Mustek MDC800 Digital Camera support"
+	help
+	  Say Y here if you want to connect this type of still camera to
+	  your computer's USB port. This driver can be used with gphoto 0.4.3
+	  and higher (look at <http://www.gphoto.org/>).
+	  To use it create a device node with "mknod /dev/mustek c 180 32" and
+	  configure it in your software.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mdc800.
+
+config USB_MICROTEK
+	tristate "Microtek X6USB scanner support"
+	depends on SCSI
+	help
+	  Say Y here if you want support for the Microtek X6USB and
+	  possibly the Phantom 336CX, Phantom C6 and ScanMaker V6U(S)L.
+	  Support for anything but the X6 is experimental.
+	  Please report failures and successes.
+	  The scanner will appear as a scsi generic device to the rest
+	  of the system. Scsi support is required.
+	  This driver can be compiled as a module, called microtek.