diff mbox series

[v6,10/14] KVM: s390: Refactor absolute vm mem_op function

Message ID 20230125212608.1860251-11-scgl@linux.ibm.com
State New
Headers
Series KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg |

Commit Message

Janis Schoetterl-Glausch Jan. 25, 2023, 9:26 p.m. UTC 
  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>
---


Cosmetic only, can be dropped.


 arch/s390/kvm/kvm-s390.c | 43 ++++++++++++++++------------------------
 1 file changed, 17 insertions(+), 26 deletions(-)

Comments

Thomas Huth Jan. 26, 2023, 12:18 p.m. UTC | #1 
On 25/01/2023 22.26, 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>
> ---
> 
> 
> Cosmetic only, can be dropped.

I'm torn between unnecessary-code-churn and 
nice-to-get-rid-of-one-indentation-level here ... anyway, patch looks sane 
to me, so:

Reviewed-by: Thomas Huth <thuth@redhat.com>
Janosch Frank Jan. 26, 2023, 1:02 p.m. UTC | #2 
On 1/26/23 13:18, Thomas Huth wrote:
> On 25/01/2023 22.26, 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>
>> ---
>>
>>
>> Cosmetic only, can be dropped.
> 
> I'm torn between unnecessary-code-churn and
> nice-to-get-rid-of-one-indentation-level here ... anyway, patch looks sane
> to me, so:
> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> 

As long as we're not adding to this function in the future then I'm 
okish with leaving it as is.
Janosch Frank Feb. 3, 2023, 2:48 p.m. UTC | #3 
On 1/25/23 22:26, 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>
> ---
> 
> 
> Cosmetic only, can be dropped.
> 
> 
>   arch/s390/kvm/kvm-s390.c | 43 ++++++++++++++++------------------------
>   1 file changed, 17 insertions(+), 26 deletions(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 588cf70dc81e..cfd09cb43ef6 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2794,6 +2794,7 @@ static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
>   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;
>   
> @@ -2813,33 +2814,23 @@ 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;
> -	}
> -	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);
> +	acc_mode = mop->op == KVM_S390_MEMOP_ABSOLUTE_READ ? GACC_FETCH : GACC_STORE;

Would the line be too long if that variable would be initialized where 
it's defined?

> +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
> +		r = check_gpa_range(kvm, mop->gaddr, mop->size, acc_mode, mop->key);

We should early return i.e. goto out_unlock.

IMHO else if, else patterns should either be switches (testing the same 
variable) or kept as short as possible / be avoided.

> +	} else if (acc_mode == GACC_FETCH) {
> +		r = access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf,
> +					      mop->size, GACC_FETCH, mop->key);

I'd guess it's personal taste whether you use GACC_FETCH or access_mode 
but if you don't use it here then we can remove the variable all 
together, no?

> +		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:
Janis Schoetterl-Glausch Feb. 3, 2023, 3:32 p.m. UTC | #4 
On Fri, 2023-02-03 at 15:48 +0100, Janosch Frank wrote:
> On 1/25/23 22:26, 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>
> > ---
> > 
> > 
> > Cosmetic only, can be dropped.
> > 
> > 
> >   arch/s390/kvm/kvm-s390.c | 43 ++++++++++++++++------------------------
> >   1 file changed, 17 insertions(+), 26 deletions(-)
> > 
> > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> > index 588cf70dc81e..cfd09cb43ef6 100644
> > --- a/arch/s390/kvm/kvm-s390.c
> > +++ b/arch/s390/kvm/kvm-s390.c
> > @@ -2794,6 +2794,7 @@ static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
> >   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;
> >   
> > @@ -2813,33 +2814,23 @@ 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;
> > -	}
> > -	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);
> > +	acc_mode = mop->op == KVM_S390_MEMOP_ABSOLUTE_READ ? GACC_FETCH : GACC_STORE;
> 
> Would the line be too long if that variable would be initialized where 
> it's defined?

Just fits at 100 columns. Want me to move it?

> 
> > +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
> > +		r = check_gpa_range(kvm, mop->gaddr, mop->size, acc_mode, mop->key);
> 
> We should early return i.e. goto out_unlock.
> 
> IMHO else if, else patterns should either be switches (testing the same 
> variable) or kept as short as possible / be avoided.
> 
> > +	} else if (acc_mode == GACC_FETCH) {
> > +		r = access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf,
> > +					      mop->size, GACC_FETCH, mop->key);
> 
> I'd guess it's personal taste whether you use GACC_FETCH or access_mode 
> but if you don't use it here then we can remove the variable all 
> together, no?

Yeah, I think I did replace it, but then undid it.
Probably just because it is a bit more explicit.
It's used in check_gpa_range, so no, unless you want to dump the expression
directly in there.
> 
> > +		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:
>
diff mbox series

Patch

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 588cf70dc81e..cfd09cb43ef6 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2794,6 +2794,7 @@  static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
 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;
 
@@ -2813,33 +2814,23 @@  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;
-	}
-	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);
+	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);
+	} else 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: