Re: [KVM PATCH v7 3/3] kvm: add iofd support

[Avi Kivity <avi@redhat.com>]

Gregory Haskins wrote:
>>> +#define KVM_IOFD_FLAG_PIO       (1 << 1)
>>> +
>>> +struct kvm_iofd {
>>> +    __u64 addr;
>>> +    __u32 len;
>>> +    __u32 fd;
>>> +    __u32 flags;
>>> +    __u8  pad[12];
>>> +};
>>> +
>>>   
>>>       
>> Please add a data match capability.  virtio uses a write with the data
>> containing the queue ID, and we want a separate event for each queue.
>>     
>
> How about "u64 cookie" ?
>   

Sure, and a bit in flags to enable it.

>>>   * kvm trace categories
>>> @@ -508,6 +519,7 @@ struct kvm_irqfd {
>>>  #define KVM_DEASSIGN_DEV_IRQ       _IOW(KVMIO, 0x75, struct
>>> kvm_assigned_irq)
>>>  #define KVM_ASSIGN_IRQFD           _IOW(KVMIO, 0x76, struct kvm_irqfd)
>>>  #define KVM_DEASSIGN_IRQFD         _IOW(KVMIO, 0x77, __u32)
>>> +#define KVM_IOFD                   _IOW(KVMIO, 0x78, struct kvm_iofd)
>>>   
>>>       
>> Too general a name.  It's not doing IO, just sending out notifications.
>>     
>
> Hmm...good point.  I was trying to reflect "[MM/P]IO-FD".  How about
> "IOSIGNALFD"
>   

Okay.

>> Why have assign/deassign for irqfd and a single ioctl for iofd?
>>     
> Heh..  irqfd "liked" two because the deassign only needed a u32.  iofd
> needed more or less the same structure for both so I guess I thought I
> would be "slick" and condense the vectors.  Will fix so they are
> symmetrical.
>   

Yeah.  You could have both use just one, or both use two.  Not sure 
which is better.

-- 
error compiling committee.c: too many arguments to function