From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH 0/1] uio_pci_generic: extensions to allow access for non-privileged processes Date: Fri, 2 Apr 2010 10:05:15 -0700 Message-ID: <20100402170515.GA32579@suse.de> References: <201003311708.38961.pugs@lyon-about.com> <201004010906.47321.pugs@lyon-about.com> <4BB4C591.8000102@redhat.com> <201004011224.45336.pugs@lyon-about.com> <4BB59217.90102@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Tom Lyon , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "Hans J. Koch" To: Avi Kivity Return-path: Received: from cantor.suse.de ([195.135.220.2]:59032 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755690Ab0DBRFS (ORCPT ); Fri, 2 Apr 2010 13:05:18 -0400 Content-Disposition: inline In-Reply-To: <4BB59217.90102@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Apr 02, 2010 at 09:43:35AM +0300, Avi Kivity wrote: > On 04/01/2010 10:24 PM, Tom Lyon wrote: >> >>> 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. >> > > Doesn't it suck for non-kvm in the same way? Multiple vectors are there > for a reason. For example, if you have a multiqueue NIC, you'd have to > process all queues instead of just the one that triggered. > >> 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? >> > > Currently kvm does device assignment with its own code, I'd like to unify > it with uio, not split it off. > > Separate notifications for msi-x interrupts are just as useful for uio as > they are for kvm. I agree, there should not be a difference here for KVM vs. the "normal" version. thanks, greg k-h