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, 46 insertions, 0 deletions

diff --git a/drivers/acpi/dptf/Kconfig b/drivers/acpi/dptf/Kconfig
new file mode 100644
index 000000000..4b3fdc03e
--- /dev/null
+++ b/drivers/acpi/dptf/Kconfig
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig ACPI_DPTF
+	bool "Intel DPTF (Dynamic Platform and Thermal Framework) Support"
+	depends on X86
+	help
+	  Intel Dynamic Platform and Thermal Framework (DPTF) is a platform
+	  level hardware/software solution for power and thermal management.
+
+	  As a container for multiple power/thermal technologies, DPTF provides
+	  a coordinated approach for different policies to effect the hardware
+	  state of a system.
+
+if ACPI_DPTF
+
+config DPTF_POWER
+	tristate "Platform Power DPTF Participant"
+	default m
+	help
+	  This driver adds support for Dynamic Platform and Thermal Framework
+	  (DPTF) Platform Power Participant device (INT3407) support.
+	  This participant is responsible for exposing platform telemetry:
+		max_platform_power
+		platform_power_source
+		adapter_rating
+		battery_steady_power
+		charger_type
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called dptf_power.
+
+config DPTF_PCH_FIVR
+	tristate "PCH FIVR DPTF Participant"
+	default m
+	help
+	  This driver adds support for Dynamic Platform and Thermal Framework
+	  (DPTF) PCH FIVR Participant device support. This driver allows to
+	  switch the PCH FIVR (Fully Integrated Voltage Regulator) frequency.
+	  This participant is responsible for exposing:
+		freq_mhz_low_clock
+		freq_mhz_high_clock
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called dptf_pch_fivr.
+
+endif