From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Auger Subject: Re: Coupling between KVM_IRQFD and KVM_SET_GSI_ROUTING? Date: Thu, 19 Jun 2014 16:02:46 +0200 Message-ID: <53A2ED86.5040507@linaro.org> References: <53A0290B.8040301@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Alexander Graf , Antonios Motakis , "kvmarm@lists.cs.columbia.edu" , Marc Zyngier , "kvm@vger.kernel.org" , Christoffer Dall Return-path: Received: from mail-wi0-f172.google.com ([209.85.212.172]:49131 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754756AbaFSODK (ORCPT ); Thu, 19 Jun 2014 10:03:10 -0400 Received: by mail-wi0-f172.google.com with SMTP id hi2so9419315wib.5 for ; Thu, 19 Jun 2014 07:03:02 -0700 (PDT) In-Reply-To: <53A0290B.8040301@linaro.org> Sender: kvm-owner@vger.kernel.org List-ID: Hi, If I am not wrong I did not get any reply to this question. Can anyone share his/her experience/knowledge on this gsi routing/irqfd use case? Thank you in advance Best Regards Eric On 06/17/2014 01:39 PM, Eric Auger wrote: > Hello, > > I have a question related to KVM_IRQFD and KVM_SET_GSI_ROUTING ioctl > relationship. > > When reading the KVM API documentation I do not understand there is any > dependency between KVM_IRQFD and KVM_SET_GSI_ROUTING. According to the > text it seems only the gsi field is used and interpreted as the irqchip pin. > > However irqchip.c kvm_set_irq code relies on an existing and not dummy > routing table. > > My question is: does anyone agree on the fact the user-side must set a > consistent routing table using KVM_SET_GSI_ROUTING before using > KVM_IRQFD? The other alternative would have been to build a default > identity GSI routing table in the kernel (gsi = irqchip.pin). > > In the positive, shouldn't we clarify the KVM API documentation? > > Thank you in advance > > Best Regards > > Eric >