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, 115 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/Kconfig b/drivers/usb/cdns3/Kconfig
new file mode 100644
index 000000000..39ad23d1a
--- /dev/null
+++ b/drivers/usb/cdns3/Kconfig
@@ -0,0 +1,115 @@
+config USB_CDNS_SUPPORT
+	tristate "Cadence USB Support"
+	depends on USB_SUPPORT && HAS_DMA
+	depends on USB || USB_GADGET
+	depends on USB if !USB_GADGET
+	depends on USB_GADGET if !USB
+	select USB_XHCI_PLATFORM if USB_XHCI_HCD
+	select USB_ROLE_SWITCH
+	help
+	  Say Y here if your system has a Cadence USBSS or USBSSP
+	  dual-role controller.
+	  It supports: dual-role switch, Host-only, and Peripheral-only.
+
+if USB_CDNS_SUPPORT
+
+config USB_CDNS3
+	tristate "Cadence USB dual-role controller (USBSS and USBSSP)"
+	depends on USB_CDNS_SUPPORT
+	help
+	  Say Y or M here if your system has an on-chip Cadence USB
+	  dual-role controller. This covers both USBSS (USB 3.0) and
+	  USBSSP (SuperSpeed Plus) IP; the driver detects the variant at
+	  runtime.
+
+	  The core driver (core, DRD, generic platform binding for the
+	  "cdns,usb3" device tree compatible, optional host and gadget)
+	  builds as one module named cdns.ko when built as a loadable
+	  module.
+
+	  It supports: dual-role switch, Host-only, and Peripheral-only.
+
+if USB_CDNS3
+
+config USB_CDNS3_HOST
+	bool "Cadence USB host controller (xHCI)"
+	depends on USB=y || USB=USB_CDNS3
+	help
+	  Say Y here to enable host controller functionality for Cadence
+	  USBSS and USBSSP dual-role controllers.
+
+	  The host controller is xHCI compliant and uses the standard
+	  xHCI driver.
+
+config USB_CDNS3_GADGET
+	bool "Cadence USB device controller (USBSS and USBSSP)"
+	depends on USB_GADGET=y || USB_GADGET=USB_CDNS3
+	help
+	  Say Y here to include Cadence USB device (gadget) support for
+	  both USBSS (USB 3.0) and USBSSP (SuperSpeed Plus) IP in the
+	  cdns.ko module. The implementation is selected at runtime from
+	  the detected controller version.
+
+	  USBSS gadget supports FF, HS and SS mode (not LS or SSP).
+	  USBSSP gadget supports FF, HS, SS and SSP mode (not LS).
+
+comment "Platform glue driver support"
+
+config USB_CDNS3_PCI_WRAP
+	tristate "Cadence USB3 support on PCIe-based platforms"
+	depends on USB_PCI && ACPI
+	default USB_CDNS3
+	help
+	  If you're using the USBSS Core IP with a PCIe, please say
+	  'Y' or 'M' here.
+
+	  If you choose to build this driver as module it will
+	  be dynamically linked and module will be called cdns3-pci.ko
+
+config USB_CDNSP_PCI
+	tristate "Cadence USBSSP support on PCIe-based platforms"
+	depends on USB_PCI && ACPI
+	default USB_CDNS3
+	help
+	  If you're using the USBSSP Core IP with a PCIe, please say
+	  'Y' or 'M' here.
+
+	  If you choose to build this driver as module it will
+	  be dynamically linked and module will be called cdnsp-pci.ko
+
+config USB_CDNS3_TI
+	tristate "Cadence USB3 support on TI platforms"
+	depends on ARCH_K3 || COMPILE_TEST
+	default USB_CDNS3
+	help
+	  Say 'Y' or 'M' here if you are building for Texas Instruments
+	  platforms that contain Cadence USB3 controller core.
+
+	  e.g. J721e.
+
+config USB_CDNS3_IMX
+	tristate "Cadence USB3 support on NXP i.MX platforms"
+	depends on ARCH_MXC || COMPILE_TEST
+	default USB_CDNS3
+	help
+	  Say 'Y' or 'M' here if you are building for NXP i.MX
+	  platforms that contain Cadence USB3 controller core.
+
+	  For example, imx8qm and imx8qxp.
+
+config USB_CDNS3_STARFIVE
+	tristate "Cadence USB3 support on StarFive SoC platforms"
+	depends on ARCH_STARFIVE || COMPILE_TEST
+	default USB_CDNS3
+	help
+	  Say 'Y' or 'M' here if you are building for StarFive SoCs
+	  platforms that contain Cadence USB3 controller core.
+
+	  e.g. JH7110.
+
+	  If you choose to build this driver as module it will
+	  be dynamically linked and module will be called cdns3-starfive.ko
+
+endif # USB_CDNS3
+
+endif # USB_CDNS_SUPPORT