Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754573AbbGFQJF (ORCPT ); Mon, 6 Jul 2015 12:09:05 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:52653 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751934AbbGFQJD (ORCPT ); Mon, 6 Jul 2015 12:09:03 -0400 Subject: Re: [PATCH 1/7] KVM: api: add kvm_irq_routing_extended_msi To: Paolo Bonzini , Pavel Fedin , "'Christoffer Dall'" References: <1435592237-17924-1-git-send-email-eric.auger@linaro.org> <1435592237-17924-2-git-send-email-eric.auger@linaro.org> <011f01d0b498$6a17aeb0$3e470c10$@samsung.com> <5596503E.6040902@arm.com> <00fd01d0b7b6$f6cf3550$e46d9ff0$@samsung.com> <559A3C9C.6050302@arm.com> <20150706093026.GA11590@cbox> <559A52E6.5050402@arm.com> <20150706103755.GC11590@cbox> <559A6164.1000401@redhat.com> <559A6527.1040107@arm.com> <559A6BBC.2040901@redhat.com> <024301d0b7f0$2b13b410$813b1c30$@samsung.com> <559AA0D6.7070703@arm.com> <559AA4CF.7060300@redhat.com> Cc: "'Eric Auger'" , "eric.auger@st.com" , "linux-arm-kernel@lists.infradead.org" , Marc Zyngier , "kvmarm@lists.cs.columbia.edu" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" From: Andre Przywara X-Enigmail-Draft-Status: N1110 Organization: ARM Ltd. Message-ID: <559AA7FA.5010804@arm.com> Date: Mon, 6 Jul 2015 17:08:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: <559AA4CF.7060300@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1067 Lines: 29 On 06/07/15 16:54, Paolo Bonzini wrote: > > > On 06/07/2015 17:37, Andre Przywara wrote: >> Wouldn't: >> if (kvm_vm_check_extension(s, KVM_CAP_MSI_DEVID)) { >> kroute.flags = KVM_MSI_VALID_DEVID; >> kroute.u.msi.devid = (pci_bus_num(dev->bus) << 8) | dev->devfn; >> } >> >> be saner (without a global variable)? >> That would make the interface more consistent, with a new flag being >> protected by a new capability. > > I agree that your version is niceer, but you still need to cache the > kvm_vm_check_extension result... in a global variable. :) I used a static variable in a wrapper function in kvmtool ;-) TBH my argument wasn't so much about global variables (just saw that QEMU seems to use them already), but more about a consistent and architecture agnostic interface. Ciao! Andre. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/