[PATCH v6 06/28] KVM: s390: Introduce import_lock

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

Introduce import_lock to avoid future races when converting pages to
secure.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 arch/s390/include/asm/kvm_host.h | 2 ++
 arch/s390/kvm/kvm-s390.c         | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index ae1223264d3c..3dbddb7c60a9 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -630,6 +630,8 @@ struct kvm_s390_pv {
 	void *set_aside;
 	struct list_head need_cleanup;
 	struct mmu_notifier mmu_notifier;
+	/* Protects against concurrent import-like operations */
+	struct mutex import_lock;
 };
 
 struct kvm_arch {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 56a50524b3ee..cd39b2f099ca 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3330,6 +3330,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	char debug_name[16];
 	int i, rc;
 
+	mutex_init(&kvm->arch.pv.import_lock);
+
 	rc = -EINVAL;
 #ifdef CONFIG_KVM_S390_UCONTROL
 	if (type & ~KVM_VM_S390_UCONTROL)
-- 
2.52.0