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, 83 insertions, 0 deletions

diff --git a/arch/mips/bmips/Kconfig b/arch/mips/bmips/Kconfig
new file mode 100644
index 000000000..63dfc6950
--- /dev/null
+++ b/arch/mips/bmips/Kconfig
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: GPL-2.0
+if BMIPS_GENERIC
+
+choice
+	prompt "Built-in device tree"
+	help
+	  Legacy bootloaders do not pass a DTB pointer to the kernel, so
+	  if a "wrapper" is not being used, the kernel will need to include
+	  a device tree that matches the target board.
+
+	  The builtin DTB will only be used if the firmware does not supply
+	  a valid DTB.
+
+config DT_NONE
+	bool "None"
+
+config DT_BCM93384WVG
+	bool "BCM93384WVG Zephyr CPU"
+	select BUILTIN_DTB
+
+config DT_BCM93384WVG_VIPER
+	bool "BCM93384WVG Viper CPU (EXPERIMENTAL)"
+	select BUILTIN_DTB
+
+config DT_BCM96368MVWG
+	bool "BCM96368MVWG"
+	select BUILTIN_DTB
+
+config DT_BCM9EJTAGPRB
+	bool "BCM9EJTAGPRB"
+	select BUILTIN_DTB
+
+config DT_BCM97125CBMB
+	bool "BCM97125CBMB"
+	select BUILTIN_DTB
+
+config DT_BCM97346DBSMB
+	bool "BCM97346DBSMB"
+	select BUILTIN_DTB
+
+config DT_BCM97358SVMB
+	bool "BCM97358SVMB"
+	select BUILTIN_DTB
+
+config DT_BCM97360SVMB
+	bool "BCM97360SVMB"
+	select BUILTIN_DTB
+
+config DT_BCM97362SVMB
+	bool "BCM97362SVMB"
+	select BUILTIN_DTB
+
+config DT_BCM97420C
+	bool "BCM97420C"
+	select BUILTIN_DTB
+
+config DT_BCM97425SVMB
+	bool "BCM97425SVMB"
+	select BUILTIN_DTB
+
+config DT_BCM97435SVMB
+	bool "BCM97435SVMB"
+	select BUILTIN_DTB
+
+config DT_COMTREND_VR3032U
+	bool "Comtrend VR-3032u"
+	select BUILTIN_DTB
+
+config DT_NETGEAR_CVG834G
+	bool "NETGEAR CVG834G"
+	select BUILTIN_DTB
+
+config DT_SFR_NEUFBOX4_SERCOMM
+	bool "SFR Neufbox 4 (Sercomm)"
+	select BUILTIN_DTB
+
+config DT_SFR_NEUFBOX6_SERCOMM
+	bool "SFR Neufbox 6 (Sercomm)"
+	select BUILTIN_DTB
+
+endchoice
+
+endif