[PATCH v1 8/8] KVM: s390: Improve kvm_s390_vm_stop_migration()
From: Claudio Imbrenda
Date: Thu Jul 02 2026 - 11:30:48 EST
There is no need to clear cmma-dirty state if the VM is not using CMMA.
Skip the CMMA-related code if CMMA is not in use.
Fixes: 6cfd47f91f6a ("KVM: s390: Fix cmma dirty tracking")
Fixes: 190df4a212a7 ("KVM: s390: CMMA tracking, ESSA emulation, migration mode")
Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
arch/s390/kvm/kvm-s390.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2ac3a9ac4698..deec673a9206 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1280,8 +1280,10 @@ static int kvm_s390_vm_stop_migration(struct kvm *kvm)
* PGSTEs might have cmma_d set.
*/
WRITE_ONCE(kvm->arch.migration_mode, 0);
- if (kvm->arch.use_cmma)
- kvm_s390_sync_request_broadcast(kvm, KVM_REQ_STOP_MIGRATION);
+ if (!kvm->arch.use_cmma)
+ return 0;
+
+ kvm_s390_sync_request_broadcast(kvm, KVM_REQ_STOP_MIGRATION);
/* Clear cmma_d on all existing PGSTEs and set cmma_dirty_pages to 0. */
gmap_set_cmma_all_clean(kvm->arch.gmap);
atomic64_set(&kvm->arch.cmma_dirty_pages, 0);
--
2.55.0