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, 57 insertions, 0 deletions

diff --git a/drivers/soc/apple/Kconfig b/drivers/soc/apple/Kconfig
new file mode 100644
index 000000000..db30c0ade
--- /dev/null
+++ b/drivers/soc/apple/Kconfig
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+if ARCH_APPLE || COMPILE_TEST
+
+menu "Apple SoC drivers"
+
+config APPLE_MAILBOX
+	tristate "Apple SoC mailboxes"
+	depends on PM
+	depends on ARCH_APPLE || (64BIT && COMPILE_TEST)
+	help
+	  Apple SoCs have various co-processors required for certain
+	  peripherals to work (NVMe, display controller, etc.). This
+	  driver adds support for the mailbox controller used to
+	  communicate with those.
+
+	  Say Y here if you have an Apple SoC.
+
+config APPLE_PMGR_MISC
+	tristate "Apple SoC PMGR miscellaneous support"
+	depends on PM
+	help
+	  The PMGR block in Apple SoCs provides high-level power state
+	  controls for SoC devices. This driver manages miscellaneous
+	  power controls.
+
+	  Say 'y' here if you have a Pro/Max/Ultra Apple SoC.
+
+config APPLE_RTKIT
+	tristate "Apple RTKit co-processor IPC protocol"
+	depends on APPLE_MAILBOX
+	depends on ARCH_APPLE || COMPILE_TEST
+	help
+	  Apple SoCs such as the M1 come with various co-processors running
+	  their proprietary RTKit operating system. This option enables support
+	  for the protocol library used to communicate with those. It is used
+	  by various client drivers.
+
+	  Say 'y' here if you have an Apple SoC.
+
+config APPLE_SART
+	tristate "Apple SART DMA address filter"
+	depends on ARCH_APPLE || COMPILE_TEST
+	help
+	  Apple SART is a simple DMA address filter used on Apple SoCs such
+	  as the M1. It is usually required for the NVMe coprocessor which does
+	  not use a proper IOMMU.
+
+	  Say 'y' here if you have an Apple SoC.
+
+config APPLE_TUNABLE
+	tristate
+	depends on ARCH_APPLE || COMPILE_TEST
+
+endmenu
+
+endif