linux-kernel - [PATCH v2 07/13] KVM: s390: pv: usage counter instead of flag

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Date:   Wed, 28 Jul 2021 16:26:25 +0200
From:   Claudio Imbrenda <imbrenda@...ux.ibm.com>
To:     kvm@...r.kernel.org
Cc:     cohuck@...hat.com, borntraeger@...ibm.com, frankja@...ux.ibm.com,
        thuth@...hat.com, pasic@...ux.ibm.com, david@...hat.com,
        linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 07/13] KVM: s390: pv: usage counter instead of flag

Use the is_protected field as a counter instead of a flag. This will
be used in upcoming patches.

Increment the counter when a secure configuration is created, and
decrement it when it is destroyed. Previously the flag was set when the
set secure parameters UVC was performed.

Signed-off-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
Acked-by: Janosch Frank <frankja@...ux.ibm.com>
---
 arch/s390/kvm/pv.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index ebb1c8d7bcb3..52e7d15a6dc7 100644
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -223,7 +223,8 @@ int kvm_s390_pv_deinit_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 	cc = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
 			   UVC_CMD_DESTROY_SEC_CONF, rc, rrc);
 	WRITE_ONCE(kvm->arch.gmap->guest_handle, 0);
-	atomic_set(&kvm->mm->context.is_protected, 0);
+	if (!cc)
+		atomic_dec(&kvm->mm->context.is_protected);
 	KVM_UV_EVENT(kvm, 3, "PROTVIRT DESTROY VM: rc %x rrc %x", *rc, *rrc);
 	WARN_ONCE(cc, "protvirt destroy vm failed rc %x rrc %x", *rc, *rrc);
 	/* Intended memory leak on "impossible" error */
@@ -264,11 +265,14 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc)
 	/* Outputs */
 	kvm->arch.pv.handle = uvcb.guest_handle;
 
+	atomic_inc(&kvm->mm->context.is_protected);
 	if (cc) {
-		if (uvcb.header.rc & UVC_RC_NEED_DESTROY)
+		if (uvcb.header.rc & UVC_RC_NEED_DESTROY) {
 			kvm_s390_pv_deinit_vm(kvm, &dummy, &dummy);
-		else
+		} else {
+			atomic_dec(&kvm->mm->context.is_protected);
 			kvm_s390_pv_dealloc_vm(kvm);
+		}
 		return -EIO;
 	}
 	kvm->arch.gmap->guest_handle = uvcb.guest_handle;
@@ -291,8 +295,6 @@ int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
 	*rrc = uvcb.header.rrc;
 	KVM_UV_EVENT(kvm, 3, "PROTVIRT VM SET PARMS: rc %x rrc %x",
 		     *rc, *rrc);
-	if (!cc)
-		atomic_set(&kvm->mm->context.is_protected, 1);
 	return cc ? -EINVAL : 0;
 }
 
-- 
2.31.1