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Date: Sun, 28 Mar 2010 10:47:54 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH v3 1/1] Shared memory uio_pci driver
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To: Avi Kivity <avi@redhat.com>
Cc: Cam Macdonell <cam@cs.ualberta.ca>, qemu-devel@nongnu.org, kvm@vger.kernel.org

On Sat, Mar 27, 2010 at 08:48:34PM +0300, Avi Kivity wrote:
> On 03/26/2010 07:14 PM, Cam Macdonell wrote:
>>
>>> I'm not familiar with the uio internals, but for the interface, an ioctl()
>>> on the fd to assign an eventfd to an MSI vector.  Similar to ioeventfd, but
>>> instead of mapping a doorbell to an eventfd, it maps a real MSI to an
>>> eventfd.
>>>      
>> uio will never support ioctls.
>
> Why not?
>
>> Maybe irqcontrol could be extended?
>>    
>
> What's irqcontrol?

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.

> -- 
> Do not meddle in the internals of kernels, for they are subtle and quick to panic.