Re: [PATCH v7 10/14] KVM: s390: Refactor absolute vm mem_op function

From: Janosch Frank <frankja@linux.ibm.com>
To: Janis Schoetterl-Glausch <scgl@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	kvm@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-s390@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Shuah Khan <shuah@kernel.org>,
	Sven Schnelle <svens@linux.ibm.com>,
	Thomas Huth <thuth@redhat.com>
Subject: Re: [PATCH v7 10/14] KVM: s390: Refactor absolute vm mem_op function
Date: Tue, 7 Feb 2023 14:22:42 +0100	[thread overview]
Message-ID: <30435adc-e86f-c96c-3795-bea6bca65c16@linux.ibm.com> (raw)
In-Reply-To: <20230206164602.138068-11-scgl@linux.ibm.com>

On 2/6/23 17:45, Janis Schoetterl-Glausch wrote:
> Remove code duplication with regards to the CHECK_ONLY flag.
> Decrease the number of indents.
> No functional change indented.
> 
> Suggested-by: Janosch Frank <frankja@linux.ibm.com>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
> 

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

> 
> Cosmetic only, can be dropped
> 
> 
>   arch/s390/kvm/kvm-s390.c | 43 +++++++++++++++++-----------------------
>   1 file changed, 18 insertions(+), 25 deletions(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 707967a296f1..1f94b18f1cb5 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2782,6 +2782,7 @@ static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_fla
>   static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op *mop)
>   {
>   	void __user *uaddr = (void __user *)mop->buf;
> +	enum gacc_mode acc_mode;
>   	void *tmpbuf = NULL;
>   	int r, srcu_idx;
>   
> @@ -2803,33 +2804,25 @@ static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op *mop)
>   		goto out_unlock;
>   	}
>   
> -	switch (mop->op) {
> -	case KVM_S390_MEMOP_ABSOLUTE_READ: {
> -		if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
> -			r = check_gpa_range(kvm, mop->gaddr, mop->size, GACC_FETCH, mop->key);
> -		} else {
> -			r = access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf,
> -						      mop->size, GACC_FETCH, mop->key);
> -			if (r == 0) {
> -				if (copy_to_user(uaddr, tmpbuf, mop->size))
> -					r = -EFAULT;
> -			}
> -		}
> -		break;
> +	acc_mode = mop->op == KVM_S390_MEMOP_ABSOLUTE_READ ? GACC_FETCH : GACC_STORE;
> +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
> +		r = check_gpa_range(kvm, mop->gaddr, mop->size, acc_mode, mop->key);
> +		goto out_unlock;
>   	}
> -	case KVM_S390_MEMOP_ABSOLUTE_WRITE: {
> -		if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
> -			r = check_gpa_range(kvm, mop->gaddr, mop->size, GACC_STORE, mop->key);
> -		} else {
> -			if (copy_from_user(tmpbuf, uaddr, mop->size)) {
> -				r = -EFAULT;
> -				break;
> -			}
> -			r = access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf,
> -						      mop->size, GACC_STORE, mop->key);
> +	if (acc_mode == GACC_FETCH) {
> +		r = access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf,
> +					      mop->size, GACC_FETCH, mop->key);
> +		if (r)
> +			goto out_unlock;
> +		if (copy_to_user(uaddr, tmpbuf, mop->size))
> +			r = -EFAULT;
> +	} else {
> +		if (copy_from_user(tmpbuf, uaddr, mop->size)) {
> +			r = -EFAULT;
> +			goto out_unlock;
>   		}
> -		break;
> -	}
> +		r = access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf,
> +					      mop->size, GACC_STORE, mop->key);
>   	}
>   
>   out_unlock: