diff mbox series

[v6,08/14] KVM: s390: Move common code of mem_op functions into functions

Message ID 20230125212608.1860251-9-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 
  The vcpu and vm mem_op ioctl implementations share some functionality.
Move argument checking and buffer allocation into functions and call
them from both implementations.
This allows code reuse in case of additional future mem_op operations.

Suggested-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
 arch/s390/kvm/kvm-s390.c | 80 +++++++++++++++++++++-------------------
 1 file changed, 42 insertions(+), 38 deletions(-)

Comments

Thomas Huth Jan. 26, 2023, 6:48 a.m. UTC | #1 
On 25/01/2023 22.26, Janis Schoetterl-Glausch wrote:
> The vcpu and vm mem_op ioctl implementations share some functionality.
> Move argument checking and buffer allocation into functions and call
> them from both implementations.
> This allows code reuse in case of additional future mem_op operations.
> 
> Suggested-by: Janosch Frank <frankja@linux.ibm.com>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
>   arch/s390/kvm/kvm-s390.c | 80 +++++++++++++++++++++-------------------
>   1 file changed, 42 insertions(+), 38 deletions(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index e4890e04b210..e0dfaa195949 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2764,24 +2764,44 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
>   	return r;
>   }
>   
> -static bool access_key_invalid(u8 access_key)
> +static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_flags)
>   {
> -	return access_key > 0xf;
> +	if (mop->flags & ~supported_flags || !mop->size)
> +		return -EINVAL;
> +	if (mop->size > MEM_OP_MAX_SIZE)
> +		return -E2BIG;
> +	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> +		if (mop->key > 0xf)
> +			return -EINVAL;
> +	} else {
> +		mop->key = 0;
> +	}
> +	return 0;
> +}
> +
> +static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
> +{
> +	void *buf;
> +
> +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)
> +		return NULL;
> +	buf = vmalloc(mop->size);
> +	if (!buf)
> +		return ERR_PTR(-ENOMEM);
> +	return buf;
>   }
>   
>   static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
>   {
>   	void __user *uaddr = (void __user *)mop->buf;
> -	u64 supported_flags;
>   	void *tmpbuf = NULL;

You likely can now remove the "= NULL" here, I guess?

>   	int r, srcu_idx;
>   
> -	supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION
> -			  | KVM_S390_MEMOP_F_CHECK_ONLY;
> -	if (mop->flags & ~supported_flags || !mop->size)
> -		return -EINVAL;
> -	if (mop->size > MEM_OP_MAX_SIZE)
> -		return -E2BIG;
> +	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION |
> +					KVM_S390_MEMOP_F_CHECK_ONLY);
> +	if (r)
> +		return r;
> +
>   	/*
>   	 * This is technically a heuristic only, if the kvm->lock is not
>   	 * taken, it is not guaranteed that the vm is/remains non-protected.
> @@ -2793,17 +2813,9 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
>   	 */
>   	if (kvm_s390_pv_get_handle(kvm))
>   		return -EINVAL;
> -	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> -		if (access_key_invalid(mop->key))
> -			return -EINVAL;
> -	} else {
> -		mop->key = 0;
> -	}
> -	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
> -		tmpbuf = vmalloc(mop->size);
> -		if (!tmpbuf)
> -			return -ENOMEM;
> -	}
> +	tmpbuf = mem_op_alloc_buf(mop);
> +	if (IS_ERR(tmpbuf))
> +		return PTR_ERR(tmpbuf);
>   
>   	srcu_idx = srcu_read_lock(&kvm->srcu);
>   
> @@ -5250,28 +5262,20 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu,
>   {
>   	void __user *uaddr = (void __user *)mop->buf;
>   	void *tmpbuf = NULL;

... and here, too.

But I have to admit that I'm also not sure whether I like the 
mem_op_alloc_buf() part or not (the mem_op_validate_common() part looks fine 
to me) : mem_op_alloc_buf() is a new function with 11 lines of code, and the 
old spots that allocate memory were only 5 lines of code each, so you now 
increased the LoC count and additionally have to fiddly with IS_ERR and 
PTR_ERR which is always a little bit ugly in my eyes ... IMHO I'd rather 
keep the old code here. But that's just my 0.02 €, if you think it's nicer 
with mem_op_alloc_buf(), I won't insist on keeping the old code.

  Thomas


> -	int r = 0;
> -	const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
> -				    | KVM_S390_MEMOP_F_CHECK_ONLY
> -				    | KVM_S390_MEMOP_F_SKEY_PROTECTION;
> +	int r;
>   
> -	if (mop->flags & ~supported_flags || mop->ar >= NUM_ACRS || !mop->size)
> +	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_INJECT_EXCEPTION |
> +					KVM_S390_MEMOP_F_CHECK_ONLY |
> +					KVM_S390_MEMOP_F_SKEY_PROTECTION);
> +	if (r)
> +		return r;
> +	if (mop->ar >= NUM_ACRS)
>   		return -EINVAL;
> -	if (mop->size > MEM_OP_MAX_SIZE)
> -		return -E2BIG;
>   	if (kvm_s390_pv_cpu_is_protected(vcpu))
>   		return -EINVAL;
> -	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> -		if (access_key_invalid(mop->key))
> -			return -EINVAL;
> -	} else {
> -		mop->key = 0;
> -	}
> -	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
> -		tmpbuf = vmalloc(mop->size);
> -		if (!tmpbuf)
> -			return -ENOMEM;
> -	}
> +	tmpbuf = mem_op_alloc_buf(mop);
> +	if (IS_ERR(tmpbuf))
> +		return PTR_ERR(tmpbuf);
>   
>   	switch (mop->op) {
>   	case KVM_S390_MEMOP_LOGICAL_READ:
Janosch Frank Jan. 26, 2023, 1:02 p.m. UTC | #2 
On 1/26/23 07:48, Thomas Huth wrote:
> On 25/01/2023 22.26, Janis Schoetterl-Glausch wrote:
>> The vcpu and vm mem_op ioctl implementations share some functionality.
>> Move argument checking and buffer allocation into functions and call
>> them from both implementations.
>> This allows code reuse in case of additional future mem_op operations.
>>
>> Suggested-by: Janosch Frank <frankja@linux.ibm.com>
>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
>> ---
>>    arch/s390/kvm/kvm-s390.c | 80 +++++++++++++++++++++-------------------
>>    1 file changed, 42 insertions(+), 38 deletions(-)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index e4890e04b210..e0dfaa195949 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -2764,24 +2764,44 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
>>    	return r;
>>    }
>>    
>> -static bool access_key_invalid(u8 access_key)
>> +static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_flags)
>>    {
>> -	return access_key > 0xf;
>> +	if (mop->flags & ~supported_flags || !mop->size)
>> +		return -EINVAL;
>> +	if (mop->size > MEM_OP_MAX_SIZE)
>> +		return -E2BIG;
>> +	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
>> +		if (mop->key > 0xf)
>> +			return -EINVAL;
>> +	} else {
>> +		mop->key = 0;
>> +	}
>> +	return 0;
>> +}
>> +
>> +static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
>> +{
>> +	void *buf;
>> +
>> +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)
>> +		return NULL;
>> +	buf = vmalloc(mop->size);
>> +	if (!buf)
>> +		return ERR_PTR(-ENOMEM);
>> +	return buf;
>>    }
>>    
>>    static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
>>    {
>>    	void __user *uaddr = (void __user *)mop->buf;
>> -	u64 supported_flags;
>>    	void *tmpbuf = NULL;
> 
> You likely can now remove the "= NULL" here, I guess?
> 
>>    	int r, srcu_idx;
>>    
>> -	supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION
>> -			  | KVM_S390_MEMOP_F_CHECK_ONLY;
>> -	if (mop->flags & ~supported_flags || !mop->size)
>> -		return -EINVAL;
>> -	if (mop->size > MEM_OP_MAX_SIZE)
>> -		return -E2BIG;
>> +	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION |
>> +					KVM_S390_MEMOP_F_CHECK_ONLY);
>> +	if (r)
>> +		return r;
>> +
>>    	/*
>>    	 * This is technically a heuristic only, if the kvm->lock is not
>>    	 * taken, it is not guaranteed that the vm is/remains non-protected.
>> @@ -2793,17 +2813,9 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
>>    	 */
>>    	if (kvm_s390_pv_get_handle(kvm))
>>    		return -EINVAL;
>> -	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
>> -		if (access_key_invalid(mop->key))
>> -			return -EINVAL;
>> -	} else {
>> -		mop->key = 0;
>> -	}
>> -	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
>> -		tmpbuf = vmalloc(mop->size);
>> -		if (!tmpbuf)
>> -			return -ENOMEM;
>> -	}
>> +	tmpbuf = mem_op_alloc_buf(mop);
>> +	if (IS_ERR(tmpbuf))
>> +		return PTR_ERR(tmpbuf);
>>    
>>    	srcu_idx = srcu_read_lock(&kvm->srcu);
>>    
>> @@ -5250,28 +5262,20 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu,
>>    {
>>    	void __user *uaddr = (void __user *)mop->buf;
>>    	void *tmpbuf = NULL;
> 
> ... and here, too.
> 
> But I have to admit that I'm also not sure whether I like the
> mem_op_alloc_buf() part or not (the mem_op_validate_common() part looks fine
> to me) : mem_op_alloc_buf() is a new function with 11 lines of code, and the
> old spots that allocate memory were only 5 lines of code each, so you now
> increased the LoC count and additionally have to fiddly with IS_ERR and
> PTR_ERR which is always a little bit ugly in my eyes ... IMHO I'd rather
> keep the old code here. But that's just my 0.02 €, if you think it's nicer
> with mem_op_alloc_buf(), I won't insist on keeping the old code.
> 
>    Thomas
> 

I've done a PoC that has a **buff argument and combines the check with 
the alloc.

@Nina: Any reason why this was split up?
Janis Schoetterl-Glausch Jan. 26, 2023, 4:47 p.m. UTC | #3 
On Thu, 2023-01-26 at 14:02 +0100, Janosch Frank wrote:
> On 1/26/23 07:48, Thomas Huth wrote:
> > On 25/01/2023 22.26, Janis Schoetterl-Glausch wrote:
> > > The vcpu and vm mem_op ioctl implementations share some functionality.
> > > Move argument checking and buffer allocation into functions and call
> > > them from both implementations.
> > > This allows code reuse in case of additional future mem_op operations.
> > > 
> > > Suggested-by: Janosch Frank <frankja@linux.ibm.com>
> > > Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> > > ---
> > >    arch/s390/kvm/kvm-s390.c | 80 +++++++++++++++++++++-------------------
> > >    1 file changed, 42 insertions(+), 38 deletions(-)
> > > 
> > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> > > index e4890e04b210..e0dfaa195949 100644
> > > --- a/arch/s390/kvm/kvm-s390.c
> > > +++ b/arch/s390/kvm/kvm-s390.c
> > > @@ -2764,24 +2764,44 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
> > >    	return r;
> > >    }
> > >    
> > > -static bool access_key_invalid(u8 access_key)
> > > +static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_flags)
> > >    {
> > > -	return access_key > 0xf;
> > > +	if (mop->flags & ~supported_flags || !mop->size)
> > > +		return -EINVAL;
> > > +	if (mop->size > MEM_OP_MAX_SIZE)
> > > +		return -E2BIG;
> > > +	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> > > +		if (mop->key > 0xf)
> > > +			return -EINVAL;
> > > +	} else {
> > > +		mop->key = 0;
> > > +	}
> > > +	return 0;
> > > +}
> > > +
> > > +static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
> > > +{
> > > +	void *buf;
> > > +
> > > +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)
> > > +		return NULL;
> > > +	buf = vmalloc(mop->size);
> > > +	if (!buf)
> > > +		return ERR_PTR(-ENOMEM);
> > > +	return buf;
> > >    }
> > >    
> > >    static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
> > >    {
> > >    	void __user *uaddr = (void __user *)mop->buf;
> > > -	u64 supported_flags;
> > >    	void *tmpbuf = NULL;
> > 
> > You likely can now remove the "= NULL" here, I guess?
> > 
> > >    	int r, srcu_idx;
> > >    
> > > -	supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION
> > > -			  | KVM_S390_MEMOP_F_CHECK_ONLY;
> > > -	if (mop->flags & ~supported_flags || !mop->size)
> > > -		return -EINVAL;
> > > -	if (mop->size > MEM_OP_MAX_SIZE)
> > > -		return -E2BIG;
> > > +	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION |
> > > +					KVM_S390_MEMOP_F_CHECK_ONLY);
> > > +	if (r)
> > > +		return r;
> > > +
> > >    	/*
> > >    	 * This is technically a heuristic only, if the kvm->lock is not
> > >    	 * taken, it is not guaranteed that the vm is/remains non-protected.
> > > @@ -2793,17 +2813,9 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
> > >    	 */
> > >    	if (kvm_s390_pv_get_handle(kvm))
> > >    		return -EINVAL;
> > > -	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> > > -		if (access_key_invalid(mop->key))
> > > -			return -EINVAL;
> > > -	} else {
> > > -		mop->key = 0;
> > > -	}
> > > -	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
> > > -		tmpbuf = vmalloc(mop->size);
> > > -		if (!tmpbuf)
> > > -			return -ENOMEM;
> > > -	}
> > > +	tmpbuf = mem_op_alloc_buf(mop);
> > > +	if (IS_ERR(tmpbuf))
> > > +		return PTR_ERR(tmpbuf);
> > >    
> > >    	srcu_idx = srcu_read_lock(&kvm->srcu);
> > >    
> > > @@ -5250,28 +5262,20 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu,
> > >    {
> > >    	void __user *uaddr = (void __user *)mop->buf;
> > >    	void *tmpbuf = NULL;
> > 
> > ... and here, too.
> > 
> > But I have to admit that I'm also not sure whether I like the
> > mem_op_alloc_buf() part or not (the mem_op_validate_common() part looks fine
> > to me) : mem_op_alloc_buf() is a new function with 11 lines of code, and the
> > old spots that allocate memory were only 5 lines of code each, so you now
> > increased the LoC count and additionally have to fiddly with IS_ERR and
> > PTR_ERR which is always a little bit ugly in my eyes ... IMHO I'd rather
> > keep the old code here. But that's just my 0.02 €, if you think it's nicer
> > with mem_op_alloc_buf(), I won't insist on keeping the old code.
> > 
> >    Thomas
> > 
> 
> I've done a PoC that has a **buff argument and combines the check with 
> the alloc.

I just didn't like that much because it felt like an unspecific memop_do_things function.
Janis Schoetterl-Glausch Jan. 26, 2023, 5:01 p.m. UTC | #4 
On Thu, 2023-01-26 at 07:48 +0100, Thomas Huth wrote:
> On 25/01/2023 22.26, Janis Schoetterl-Glausch wrote:
> > The vcpu and vm mem_op ioctl implementations share some functionality.
> > Move argument checking and buffer allocation into functions and call
> > them from both implementations.
> > This allows code reuse in case of additional future mem_op operations.
> > 
> > Suggested-by: Janosch Frank <frankja@linux.ibm.com>
> > Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> > ---
> >   arch/s390/kvm/kvm-s390.c | 80 +++++++++++++++++++++-------------------
> >   1 file changed, 42 insertions(+), 38 deletions(-)
> > 
> > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> > index e4890e04b210..e0dfaa195949 100644
> > --- a/arch/s390/kvm/kvm-s390.c
> > +++ b/arch/s390/kvm/kvm-s390.c
> > @@ -2764,24 +2764,44 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
> >   	return r;
> >   }
> >   
> > -static bool access_key_invalid(u8 access_key)
> > +static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_flags)
> >   {
> > -	return access_key > 0xf;
> > +	if (mop->flags & ~supported_flags || !mop->size)
> > +		return -EINVAL;
> > +	if (mop->size > MEM_OP_MAX_SIZE)
> > +		return -E2BIG;
> > +	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> > +		if (mop->key > 0xf)
> > +			return -EINVAL;
> > +	} else {
> > +		mop->key = 0;
> > +	}
> > +	return 0;
> > +}
> > +
> > +static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
> > +{
> > +	void *buf;
> > +
> > +	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)
> > +		return NULL;
> > +	buf = vmalloc(mop->size);
> > +	if (!buf)
> > +		return ERR_PTR(-ENOMEM);
> > +	return buf;
> >   }
> >   
> >   static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
> >   {
> >   	void __user *uaddr = (void __user *)mop->buf;
> > -	u64 supported_flags;
> >   	void *tmpbuf = NULL;
> 
> You likely can now remove the "= NULL" here, I guess?

Yeah, I thought about it, but wasn't sure if I like moving the line down because of
some people's insistence on reverse christmas tree.
It's entirely arbitrary in a different way, but I like the return value being the last
thing declared.
In the end I forgot to make a decision on it.

> 
> >   	int r, srcu_idx;
> >   
> > -	supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION
> > -			  | KVM_S390_MEMOP_F_CHECK_ONLY;
> > -	if (mop->flags & ~supported_flags || !mop->size)
> > -		return -EINVAL;
> > -	if (mop->size > MEM_OP_MAX_SIZE)
> > -		return -E2BIG;
> > +	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION |
> > +					KVM_S390_MEMOP_F_CHECK_ONLY);
> > +	if (r)
> > +		return r;
> > +
> >   	/*
> >   	 * This is technically a heuristic only, if the kvm->lock is not
> >   	 * taken, it is not guaranteed that the vm is/remains non-protected.
> > @@ -2793,17 +2813,9 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
> >   	 */
> >   	if (kvm_s390_pv_get_handle(kvm))
> >   		return -EINVAL;
> > -	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> > -		if (access_key_invalid(mop->key))
> > -			return -EINVAL;
> > -	} else {
> > -		mop->key = 0;
> > -	}
> > -	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
> > -		tmpbuf = vmalloc(mop->size);
> > -		if (!tmpbuf)
> > -			return -ENOMEM;
> > -	}
> > +	tmpbuf = mem_op_alloc_buf(mop);
> > +	if (IS_ERR(tmpbuf))
> > +		return PTR_ERR(tmpbuf);
> >   
> >   	srcu_idx = srcu_read_lock(&kvm->srcu);
> >   
> > @@ -5250,28 +5262,20 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu,
> >   {
> >   	void __user *uaddr = (void __user *)mop->buf;
> >   	void *tmpbuf = NULL;
> 
> ... and here, too.
> 
> But I have to admit that I'm also not sure whether I like the 
> mem_op_alloc_buf() part or not (the mem_op_validate_common() part looks fine 
> to me) : mem_op_alloc_buf() is a new function with 11 lines of code, and the 
> old spots that allocate memory were only 5 lines of code each, so you now 
> increased the LoC count and additionally have to fiddly with IS_ERR and 
> PTR_ERR which is always a little bit ugly in my eyes ... IMHO I'd rather 
> keep the old code here. But that's just my 0.02 €, if you think it's nicer 
> with mem_op_alloc_buf(), I won't insist on keeping the old code.

Yeah, that's fair.

> 
>   Thomas
> 
> 
> > -	int r = 0;
> > -	const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
> > -				    | KVM_S390_MEMOP_F_CHECK_ONLY
> > -				    | KVM_S390_MEMOP_F_SKEY_PROTECTION;
> > +	int r;
> >   
> > -	if (mop->flags & ~supported_flags || mop->ar >= NUM_ACRS || !mop->size)
> > +	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_INJECT_EXCEPTION |
> > +					KVM_S390_MEMOP_F_CHECK_ONLY |
> > +					KVM_S390_MEMOP_F_SKEY_PROTECTION);
> > +	if (r)
> > +		return r;
> > +	if (mop->ar >= NUM_ACRS)
> >   		return -EINVAL;
> > -	if (mop->size > MEM_OP_MAX_SIZE)
> > -		return -E2BIG;
> >   	if (kvm_s390_pv_cpu_is_protected(vcpu))
> >   		return -EINVAL;
> > -	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
> > -		if (access_key_invalid(mop->key))
> > -			return -EINVAL;
> > -	} else {
> > -		mop->key = 0;
> > -	}
> > -	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
> > -		tmpbuf = vmalloc(mop->size);
> > -		if (!tmpbuf)
> > -			return -ENOMEM;
> > -	}
> > +	tmpbuf = mem_op_alloc_buf(mop);
> > +	if (IS_ERR(tmpbuf))
> > +		return PTR_ERR(tmpbuf);
> >   
> >   	switch (mop->op) {
> >   	case KVM_S390_MEMOP_LOGICAL_READ:
>
diff mbox series

Patch

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index e4890e04b210..e0dfaa195949 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2764,24 +2764,44 @@  static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 	return r;
 }
 
-static bool access_key_invalid(u8 access_key)
+static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_flags)
 {
-	return access_key > 0xf;
+	if (mop->flags & ~supported_flags || !mop->size)
+		return -EINVAL;
+	if (mop->size > MEM_OP_MAX_SIZE)
+		return -E2BIG;
+	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
+		if (mop->key > 0xf)
+			return -EINVAL;
+	} else {
+		mop->key = 0;
+	}
+	return 0;
+}
+
+static void *mem_op_alloc_buf(struct kvm_s390_mem_op *mop)
+{
+	void *buf;
+
+	if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)
+		return NULL;
+	buf = vmalloc(mop->size);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+	return buf;
 }
 
 static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
 {
 	void __user *uaddr = (void __user *)mop->buf;
-	u64 supported_flags;
 	void *tmpbuf = NULL;
 	int r, srcu_idx;
 
-	supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION
-			  | KVM_S390_MEMOP_F_CHECK_ONLY;
-	if (mop->flags & ~supported_flags || !mop->size)
-		return -EINVAL;
-	if (mop->size > MEM_OP_MAX_SIZE)
-		return -E2BIG;
+	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION |
+					KVM_S390_MEMOP_F_CHECK_ONLY);
+	if (r)
+		return r;
+
 	/*
 	 * This is technically a heuristic only, if the kvm->lock is not
 	 * taken, it is not guaranteed that the vm is/remains non-protected.
@@ -2793,17 +2813,9 @@  static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
 	 */
 	if (kvm_s390_pv_get_handle(kvm))
 		return -EINVAL;
-	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
-		if (access_key_invalid(mop->key))
-			return -EINVAL;
-	} else {
-		mop->key = 0;
-	}
-	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
-		tmpbuf = vmalloc(mop->size);
-		if (!tmpbuf)
-			return -ENOMEM;
-	}
+	tmpbuf = mem_op_alloc_buf(mop);
+	if (IS_ERR(tmpbuf))
+		return PTR_ERR(tmpbuf);
 
 	srcu_idx = srcu_read_lock(&kvm->srcu);
 
@@ -5250,28 +5262,20 @@  static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu,
 {
 	void __user *uaddr = (void __user *)mop->buf;
 	void *tmpbuf = NULL;
-	int r = 0;
-	const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
-				    | KVM_S390_MEMOP_F_CHECK_ONLY
-				    | KVM_S390_MEMOP_F_SKEY_PROTECTION;
+	int r;
 
-	if (mop->flags & ~supported_flags || mop->ar >= NUM_ACRS || !mop->size)
+	r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_INJECT_EXCEPTION |
+					KVM_S390_MEMOP_F_CHECK_ONLY |
+					KVM_S390_MEMOP_F_SKEY_PROTECTION);
+	if (r)
+		return r;
+	if (mop->ar >= NUM_ACRS)
 		return -EINVAL;
-	if (mop->size > MEM_OP_MAX_SIZE)
-		return -E2BIG;
 	if (kvm_s390_pv_cpu_is_protected(vcpu))
 		return -EINVAL;
-	if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
-		if (access_key_invalid(mop->key))
-			return -EINVAL;
-	} else {
-		mop->key = 0;
-	}
-	if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
-		tmpbuf = vmalloc(mop->size);
-		if (!tmpbuf)
-			return -ENOMEM;
-	}
+	tmpbuf = mem_op_alloc_buf(mop);
+	if (IS_ERR(tmpbuf))
+		return PTR_ERR(tmpbuf);
 
 	switch (mop->op) {
 	case KVM_S390_MEMOP_LOGICAL_READ: