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, 36 insertions, 0 deletions

diff --git a/drivers/reset/spacemit/Kconfig b/drivers/reset/spacemit/Kconfig
new file mode 100644
index 000000000..545d6b41c
--- /dev/null
+++ b/drivers/reset/spacemit/Kconfig
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menu "Reset support for SpacemiT platforms"
+	depends on ARCH_SPACEMIT || COMPILE_TEST
+
+config RESET_SPACEMIT_COMMON
+	tristate
+	select AUXILIARY_BUS
+	help
+	  Common reset controller infrastructure for SpacemiT SoCs.
+	  This provides shared code and helper functions used by
+	  reset drivers for various SpacemiT SoC families.
+
+config RESET_SPACEMIT_K1
+	tristate "Support for SpacemiT K1 SoC"
+	depends on SPACEMIT_K1_CCU
+	select RESET_SPACEMIT_COMMON
+	default SPACEMIT_K1_CCU
+	help
+	  Support for reset controller in SpacemiT K1 SoC.
+	  This driver works with the SpacemiT K1 clock controller
+	  unit (CCU) driver to provide reset control functionality
+	  for various peripherals and subsystems in the SoC.
+
+config RESET_SPACEMIT_K3
+	tristate "Support for SpacemiT K3 SoC"
+	depends on SPACEMIT_K3_CCU
+	select RESET_SPACEMIT_COMMON
+	default SPACEMIT_K3_CCU
+	help
+	  Support for reset controller in SpacemiT K3 SoC.
+	  This driver works with the SpacemiT K3 clock controller
+	  unit (CCU) driver to provide reset control functionality
+	  for various peripherals and subsystems in the SoC.
+
+endmenu