linux-kernel - [PATCH v9 08/18] KVM: s390: pv: clear the state without memset

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Date:   Wed, 30 Mar 2022 14:25:55 +0200
From:   Claudio Imbrenda <imbrenda@...ux.ibm.com>
To:     kvm@...r.kernel.org
Cc:     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, scgl@...ux.ibm.com,
        mimu@...ux.ibm.com, nrb@...ux.ibm.com
Subject: [PATCH v9 08/18] KVM: s390: pv: clear the state without memset

Do not use memset to clean the whole struct kvm_s390_pv; instead,
explicitly clear the fields that need to be cleared.

Upcoming patches will introduce new fields in the struct kvm_s390_pv
that will not need to be cleared.

Signed-off-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
Reviewed-by: Janosch Frank <frankja@...ux.ibm.com>
---
 arch/s390/kvm/pv.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index 9e900ce7387d..76ef33a277d3 100644
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -16,6 +16,14 @@
 #include <linux/sched/mm.h>
 #include "kvm-s390.h"
 
+static void kvm_s390_clear_pv_state(struct kvm *kvm)
+{
+	kvm->arch.pv.handle = 0;
+	kvm->arch.pv.guest_len = 0;
+	kvm->arch.pv.stor_base = 0;
+	kvm->arch.pv.stor_var = NULL;
+}
+
 int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc)
 {
 	int cc;
@@ -110,7 +118,7 @@ static void kvm_s390_pv_dealloc_vm(struct kvm *kvm)
 	vfree(kvm->arch.pv.stor_var);
 	free_pages(kvm->arch.pv.stor_base,
 		   get_order(uv_info.guest_base_stor_len));
-	memset(&kvm->arch.pv, 0, sizeof(kvm->arch.pv));
+	kvm_s390_clear_pv_state(kvm);
 }
 
 static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
-- 
2.34.1