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, 62 insertions, 0 deletions

diff --git a/drivers/usb/isp1760/Kconfig b/drivers/usb/isp1760/Kconfig
new file mode 100644
index 000000000..e19178f3c
--- /dev/null
+++ b/drivers/usb/isp1760/Kconfig
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_ISP1760
+	tristate "NXP ISP 1760/1761/1763 support"
+	depends on USB || USB_GADGET
+	select REGMAP_MMIO
+	help
+	  Say Y or M here if your system as an ISP1760/1763 USB host controller
+	  or an ISP1761 USB dual-role controller.
+
+	  This driver does not support isochronous transfers or OTG.
+	  This USB controller is usually attached to a non-DMA-Master
+	  capable bus. NXP's eval kit brings this chip on PCI card
+	  where the chip itself is behind a PLB to simulate such
+	  a bus.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called isp1760.
+
+config USB_ISP1760_HCD
+	bool
+
+config USB_ISP1761_UDC
+	bool
+
+if USB_ISP1760
+
+choice
+	prompt "ISP1760 Mode Selection"
+	default USB_ISP1760_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_ISP1760_HOST_ROLE if (USB && !USB_GADGET)
+	default USB_ISP1760_GADGET_ROLE if (!USB && USB_GADGET)
+
+config USB_ISP1760_HOST_ROLE
+	bool "Host only mode"
+	depends on USB=y || USB=USB_ISP1760
+	select USB_ISP1760_HCD
+	help
+	  Select this if you want to use the ISP1760 in host mode only. The
+	  gadget function will be disabled.
+
+config USB_ISP1760_GADGET_ROLE
+	bool "Gadget only mode"
+	depends on USB_GADGET=y || USB_GADGET=USB_ISP1760
+	select USB_ISP1761_UDC
+	help
+	  Select this if you want to use the ISP1760 in peripheral mode only.
+	  The host function will be disabled.
+
+config USB_ISP1760_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on USB=y || USB=USB_ISP1760
+	depends on USB_GADGET=y || USB_GADGET=USB_ISP1760
+	select USB_ISP1760_HCD
+	select USB_ISP1761_UDC
+	help
+	  Select this if you want to use the ISP1760 in both host and
+	  peripheral modes.
+
+endchoice
+
+endif