[Qemu-devel] Re: [PATCH v3 1/1] Shared memory uio_pci driver

["Michael S. Tsirkin" <mst@redhat.com>]

On Sun, Mar 28, 2010 at 12:45:02PM +0300, Avi Kivity wrote:
> On 03/28/2010 12:40 PM, Michael S. Tsirkin wrote:
>>>> uio accepts 32 bit writes to the char device file. We can encode
>>>> the fd number there, and use the high bit to signal assign/deassign.
>>>>
>>>>        
>>> Ugh.  Very unexpandable.
>>>      
>> It currently fails on any non-4 byte write.
>> So if we need more bits in the future we can always teach it
>> about e.g. 8 byte writes.
>>
>> Do you think it's worth it doing it now already, and using
>> 8 byte writes for msi mapping?
>>    
>
> Aren't ioctls a lot simpler?
>
> Multiplexing multiple functions on write()s is just ioctls done uglier.

I don't have an opinion here.

Writes do have an advantage that strace can show the buffer
content without being patched.

Further, something along the lines proposed above means that
we do not need to depend in a system header to get
the functionality.

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