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, 30 insertions, 0 deletions

diff --git a/drivers/acpi/sleep.h b/drivers/acpi/sleep.h
new file mode 100644
index 000000000..9c3cb109c
--- /dev/null
+++ b/drivers/acpi/sleep.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+extern void acpi_enable_wakeup_devices(u8 sleep_state);
+extern void acpi_disable_wakeup_devices(u8 sleep_state);
+extern bool acpi_check_wakeup_handlers(void);
+
+extern struct list_head acpi_wakeup_device_list;
+extern struct mutex acpi_device_lock;
+
+extern void acpi_resume_power_resources(void);
+
+static inline acpi_status acpi_set_waking_vector(u32 wakeup_address)
+{
+	return acpi_set_firmware_waking_vector(
+				(acpi_physical_address)wakeup_address, 0);
+}
+
+extern int acpi_s2idle_begin(void);
+extern int acpi_s2idle_prepare(void);
+extern bool acpi_s2idle_wake(void);
+extern void acpi_s2idle_restore(void);
+extern void acpi_s2idle_end(void);
+
+extern void acpi_s2idle_setup(void);
+
+#ifdef CONFIG_ACPI_SLEEP
+extern bool acpi_sleep_default_s3;
+#else
+#define acpi_sleep_default_s3	(1)
+#endif