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, 97 insertions, 0 deletions

diff --git a/drivers/usb/dwc2/Kconfig b/drivers/usb/dwc2/Kconfig
new file mode 100644
index 000000000..d7af55a8e
--- /dev/null
+++ b/drivers/usb/dwc2/Kconfig
@@ -0,0 +1,97 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_DWC2
+	tristate "DesignWare USB2 DRD Core Support"
+	depends on HAS_DMA
+	depends on USB || USB_GADGET
+	depends on HAS_IOMEM
+	select USB_ROLE_SWITCH
+	help
+	  Say Y here if your system has a Dual Role Hi-Speed USB
+	  controller based on the DesignWare HSOTG IP Core.
+
+	  For host mode, if you choose to build the driver as dynamically
+	  linked modules, the core module will be called dwc2.ko, the PCI
+	  bus interface module (if you have a PCI bus system) will be
+	  called dwc2_pci.ko, and the platform interface module (for
+	  controllers directly connected to the CPU) will be called
+	  dwc2_platform.ko. For all modes(host, gadget and dual-role), there
+	  will be an additional module named dwc2.ko.
+
+if USB_DWC2
+
+choice
+	prompt "DWC2 Mode Selection"
+	default USB_DWC2_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_DWC2_HOST if (USB && !USB_GADGET)
+	default USB_DWC2_PERIPHERAL if (!USB && USB_GADGET)
+
+config USB_DWC2_HOST
+	bool "Host only mode"
+	depends on USB=y || (USB_DWC2=m && USB)
+	help
+	  The Designware USB2.0 high-speed host controller
+	  integrated into many SoCs. Select this option if you want the
+	  driver to operate in Host-only mode.
+
+comment "Gadget/Dual-role mode requires USB Gadget support to be enabled"
+
+config USB_DWC2_PERIPHERAL
+	bool "Gadget only mode"
+	depends on USB_GADGET=y || USB_GADGET=USB_DWC2
+	help
+	  The Designware USB2.0 high-speed gadget controller
+	  integrated into many SoCs. Select this option if you want the
+	  driver to operate in Peripheral-only mode. This option requires
+	  USB_GADGET to be enabled.
+
+config USB_DWC2_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on (USB=y && USB_GADGET=y) || (USB_DWC2=m && USB && USB_GADGET)
+	help
+	  Select this option if you want the driver to work in a dual-role
+	  mode. In this mode both host and gadget features are enabled, and
+	  the role will be determined by the cable that gets plugged-in. This
+	  option requires USB_GADGET to be enabled.
+endchoice
+
+config USB_DWC2_PCI
+	tristate "DWC2 PCI"
+	depends on USB_PCI
+	depends on USB_GADGET || !USB_GADGET
+	select NOP_USB_XCEIV
+	help
+	  The Designware USB2.0 PCI interface module for controllers
+	  connected to a PCI bus.
+
+config USB_DWC2_DEBUG
+	bool "Enable Debugging Messages"
+	help
+	  Say Y here to enable debugging messages in the DWC2 Driver.
+
+config USB_DWC2_VERBOSE
+	bool "Enable Verbose Debugging Messages"
+	depends on USB_DWC2_DEBUG
+	help
+	  Say Y here to enable verbose debugging messages in the DWC2 Driver.
+	  WARNING: Enabling this will quickly fill your message log.
+	  If in doubt, say N.
+
+config USB_DWC2_TRACK_MISSED_SOFS
+	bool "Enable Missed SOF Tracking"
+	help
+	  Say Y here to enable logging of missed SOF events to the dmesg log.
+	  WARNING: This feature is still experimental.
+	  If in doubt, say N.
+
+config USB_DWC2_DEBUG_PERIODIC
+	bool "Enable Debugging Messages For Periodic Transfers"
+	depends on USB_DWC2_DEBUG || USB_DWC2_VERBOSE
+	default y
+	help
+	  Say N here to disable (verbose) debugging messages to be
+	  logged for periodic transfers. This allows better debugging of
+	  non-periodic transfers, but of course the debug logs will be
+	  incomplete. Note that this also disables some debug messages
+	  for which the transfer type cannot be deduced.
+endif