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, 68 insertions, 0 deletions

diff --git a/drivers/usb/atm/Kconfig b/drivers/usb/atm/Kconfig
new file mode 100644
index 000000000..3d958a1a1
--- /dev/null
+++ b/drivers/usb/atm/Kconfig
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB/ATM DSL configuration
+#
+
+menuconfig USB_ATM
+	tristate "USB DSL modem support"
+	depends on ATM
+	select CRC32
+	help
+	  Say Y here if you want to connect a USB Digital Subscriber Line (DSL)
+	  modem to your computer's USB port.  You will then need to choose your
+	  modem from the list below.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usbatm.
+
+if USB_ATM
+
+config USB_SPEEDTOUCH
+	tristate "Speedtouch USB support"
+	select FW_LOADER
+	help
+	  Say Y here if you have an SpeedTouch USB or SpeedTouch 330
+	  modem.  In order to use your modem you will need to install the 
+	  two parts of the firmware, extracted by the user space tools; see
+	  <http://www.linux-usb.org/SpeedTouch/> for details.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called speedtch.
+
+config USB_CXACRU
+	tristate "Conexant AccessRunner USB support"
+	select FW_LOADER
+	help
+	  Say Y here if you have an ADSL USB modem based on the Conexant
+	  AccessRunner chipset.  In order to use your modem you will need to
+	  install the firmware, extracted by the user space tools; see
+	  <http://accessrunner.sourceforge.net/> for details.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cxacru.
+
+config USB_UEAGLEATM
+	tristate "ADI 930 and eagle USB DSL modem"
+	select FW_LOADER
+	help
+	  Say Y here if you have an ADSL USB modem based on the ADI 930
+	  or eagle chipset. In order to use your modem you will need to
+	  install firmwares and CMV (Command Management Variables); see
+	  <https://gna.org/projects/ueagleatm/> for details.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ueagle-atm.
+
+config USB_XUSBATM
+	tristate "Other USB DSL modem support"
+	help
+	  Say Y here if you have a DSL USB modem not explicitly supported by
+	  another USB DSL drivers.  In order to use your modem you will need to
+	  pass the vendor ID, product ID, and endpoint numbers for transmission
+	  and reception as module parameters.  You may need to initialize
+	  the modem using a user space utility (a firmware loader for example).
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called xusbatm.
+
+endif # USB_ATM