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, 162 insertions, 0 deletions

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
new file mode 100644
index 000000000..abf8c6cde
--- /dev/null
+++ b/drivers/usb/Kconfig
@@ -0,0 +1,162 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB device configuration
+#
+
+config USB_OHCI_BIG_ENDIAN_DESC
+	bool
+
+config USB_OHCI_BIG_ENDIAN_MMIO
+	bool
+
+config USB_OHCI_LITTLE_ENDIAN
+	bool
+	default n if PPC_MPC52xx
+	default y
+
+config USB_EHCI_BIG_ENDIAN_MMIO
+	bool
+
+config USB_EHCI_BIG_ENDIAN_DESC
+	bool
+
+config USB_UHCI_BIG_ENDIAN_MMIO
+	bool
+
+config USB_UHCI_BIG_ENDIAN_DESC
+	bool
+
+menuconfig USB_SUPPORT
+	bool "USB support"
+	depends on HAS_IOMEM
+	default y
+	help
+	  This option adds core support for Universal Serial Bus (USB).
+	  You will also need drivers from the following menu to make use of it.
+
+if USB_SUPPORT
+
+source "drivers/usb/common/Kconfig"
+
+config USB_ARCH_HAS_HCD
+	def_bool y
+
+config USB
+	tristate "Support for Host-side USB"
+	depends on USB_ARCH_HAS_HCD
+	select GENERIC_ALLOCATOR
+	select USB_COMMON
+	select NLS  # for UTF-8 strings
+	help
+	  Universal Serial Bus (USB) is a specification for a serial bus
+	  subsystem which offers higher speeds and more features than the
+	  traditional PC serial port.  The bus supplies power to peripherals
+	  and allows for hot swapping.  Up to 127 USB peripherals can be
+	  connected to a single USB host in a tree structure.
+	  
+	  The USB host is the root of the tree, the peripherals are the
+	  leaves and the inner nodes are special USB devices called hubs.
+	  Most PCs now have USB host ports, used to connect peripherals
+	  such as scanners, keyboards, mice, modems, cameras, disks,
+	  flash memory, network links, and printers to the PC.
+
+	  Say Y here if your computer has a host-side USB port and you want
+	  to use USB devices.  You then need to say Y to at least one of the
+	  Host Controller Driver (HCD) options below.  Choose a USB 1.1
+	  controller, such as "UHCI HCD support" or "OHCI HCD support",
+	  and "EHCI HCD (USB 2.0) support" except for older systems that
+	  do not have USB 2.0 support.  It doesn't normally hurt to select
+	  them all if you are not certain.
+
+	  If your system has a device-side USB port, used in the peripheral
+	  side of the USB protocol, see the "USB Gadget" framework instead.
+
+	  After choosing your HCD, then select drivers for the USB peripherals
+	  you'll be using.  You may want to check out the information provided
+	  in <file:Documentation/usb/> and especially the links given in
+	  <file:Documentation/usb/usb-help.rst>.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usbcore.
+
+config USB_PCI
+	bool "PCI based USB host interface"
+	depends on PCI
+	default y
+	help
+	  Many embedded system SOCs (e.g. freescale T2080) have both
+	  PCI and USB modules with the USB module directly controlled by
+	  registers and having no relationship to the PCI module.
+
+	  If you have such a device you may say N here and PCI related code
+	  will not be built in the USB driver.
+
+config USB_PCI_AMD
+	bool "AMD PCI USB host support"
+	depends on USB_PCI && HAS_IOPORT
+	default X86 || MACH_LOONGSON64 || PPC_PASEMI
+	help
+	  Enable workarounds for USB implementation quirks in SB600/SB700/SB800
+	  and later south bridge implementations. These are common on x86 PCs
+	  with AMD CPUs but rarely used elsewhere, with the exception of a few
+	  powerpc and mips desktop machines.
+
+if USB
+
+source "drivers/usb/core/Kconfig"
+
+source "drivers/usb/mon/Kconfig"
+
+source "drivers/usb/host/Kconfig"
+
+source "drivers/usb/renesas_usbhs/Kconfig"
+
+source "drivers/usb/class/Kconfig"
+
+source "drivers/usb/storage/Kconfig"
+
+source "drivers/usb/image/Kconfig"
+
+source "drivers/usb/usbip/Kconfig"
+
+endif
+
+comment "USB dual-mode controller drivers"
+
+source "drivers/usb/cdns3/Kconfig"
+
+source "drivers/usb/fotg210/Kconfig"
+
+source "drivers/usb/mtu3/Kconfig"
+
+source "drivers/usb/musb/Kconfig"
+
+source "drivers/usb/dwc3/Kconfig"
+
+source "drivers/usb/dwc2/Kconfig"
+
+source "drivers/usb/chipidea/Kconfig"
+
+source "drivers/usb/isp1760/Kconfig"
+
+comment "USB port drivers"
+
+if USB
+
+source "drivers/usb/serial/Kconfig"
+
+source "drivers/usb/misc/Kconfig"
+
+source "drivers/usb/atm/Kconfig"
+
+endif # USB
+
+source "drivers/usb/phy/Kconfig"
+
+source "drivers/usb/gadget/Kconfig"
+
+source "drivers/usb/typec/Kconfig"
+
+source "drivers/usb/roles/Kconfig"
+
+endif # USB_SUPPORT