On Thursday 01 April 2010 09:10:57 am Avi Kivity wrote: > 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? You don't. This would suck for KVM, I guess, but we'd need major rework of the generic UIO stuff to have a separate event channel for each MSI-X. For my purposes, collapsing all the MSI-Xs into one MSI-look-alike is fine, because I'd be using MSI anyways if I could. The weird Intel 82599 VF only supports MSI-X. So one big question is - do we expand the whole UIO framework for KVM requirements, or do we split off either KVM or non-VM into a separate driver? Hans or Greg - care to opine? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
