Re: [PATCH V4 1/4] kvm: factor out core eventfd assign/deassign logic

[Jason Wang <jasowang@redhat.com>]

On 09/11/2015 03:39 PM, Cornelia Huck wrote:
> On Fri, 11 Sep 2015 11:17:34 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
>> This patch factors out core eventfd assign/deassign logic and leave
>> the argument checking and bus index selection to callers.
>>
>> Cc: Gleb Natapov <gleb@kernel.org>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  virt/kvm/eventfd.c | 83 ++++++++++++++++++++++++++++++++----------------------
>>  1 file changed, 49 insertions(+), 34 deletions(-)
>>
>> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
>> index 9ff4193..163258d 100644
>> --- a/virt/kvm/eventfd.c
>> +++ b/virt/kvm/eventfd.c
>> @@ -771,40 +771,14 @@ static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
>>  	return KVM_MMIO_BUS;
>>  }
>>
>> -static int
>> -kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
>> +static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
>> +				enum kvm_bus bus_idx,
>> +				struct kvm_ioeventfd *args)
>>  {
>> -	enum kvm_bus              bus_idx;
>> -	struct _ioeventfd        *p;
>> -	struct eventfd_ctx       *eventfd;
>> -	int                       ret;
>> -
>> -	bus_idx = ioeventfd_bus_from_flags(args->flags);
>> -	/* must be natural-word sized, or 0 to ignore length */
>> -	switch (args->len) {
>> -	case 0:
>> -	case 1:
>> -	case 2:
>> -	case 4:
>> -	case 8:
>> -		break;
>> -	default:
>> -		return -EINVAL;
>> -	}
>>
>> -	/* check for range overflow */
>> -	if (args->addr + args->len < args->addr)
>> -		return -EINVAL;
>> -
>> -	/* check for extra flags that we don't understand */
>> -	if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
>> -		return -EINVAL;
>> -
>> -	/* ioeventfd with no length can't be combined with DATAMATCH */
>> -	if (!args->len &&
>> -	    args->flags & (KVM_IOEVENTFD_FLAG_PIO |
>> -			   KVM_IOEVENTFD_FLAG_DATAMATCH))
>> -		return -EINVAL;
>> +	struct eventfd_ctx *eventfd;
>> +	struct _ioeventfd *p;
>> +	int ret;
>>
>>  	eventfd = eventfd_ctx_fdget(args->fd);
>>  	if (IS_ERR(eventfd))
>> @@ -873,14 +847,48 @@ fail:
>>  }
>>
>>  static int
>> -kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
>> +kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
> You'll move this function to below the deassign function in patch 2.
> Maybe do it already here?
>

Yes, this can reduce the changes for patch2.