Re: [PATCH 0/1] uio_pci_generic: extensions to allow access for non-privileged processes

Avi Kivity
2010-04-01T16:10:57Z

On 04/01/2010 07:06 PM, Tom Lyon wrote:
> On Thursday 01 April 2010 08:54:14 am Avi Kivity wrote:
>
>> On 04/01/2010 06:39 PM, Tom Lyon wrote:
>>
>>>>> - support for MSI and MSI-X interrupts (the intel 82599 VFs support
>>>>> only MSI-X)
>>>>>
>>>> How does a userspace program receive those interrupts?
>>>>
>>> Same as other UIO drivers - by read()ing an event counter.
>>>
>> IIRC the usual event counter is /dev/uioX, what's your event counter now?
>>
> Exact same mechanism.
>

But there are multiple msi-x interrupts, how do you know which one
triggered?

>> kvm really wants the event counter to be an eventfd, that allows hooking
>> it directly to kvm (which can inject an interrupt on an eventfd_signal),
>> can you adapt your patch to do this?
>>
> My patch does not currently go anywhere near the read/fd logic of /dev/uioX.
> I think a separate patch would be appropriate.
>

Sure.

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