Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932725Ab3E0O07 (ORCPT ); Mon, 27 May 2013 10:26:59 -0400 Received: from mail-pb0-f42.google.com ([209.85.160.42]:64704 "EHLO mail-pb0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932643Ab3E0O04 (ORCPT ); Mon, 27 May 2013 10:26:56 -0400 Message-ID: <51A36D28.7090202@ozlabs.ru> Date: Tue, 28 May 2013 00:26:48 +1000 From: Alexey Kardashevskiy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130402 Thunderbird/17.0.5 MIME-Version: 1.0 To: Paolo Bonzini CC: David Gibson , Scott Wood , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, Alexander Graf , Paul Mackerras , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 3/4] KVM: PPC: Add support for IOMMU in-kernel handling References: <1369105607-20957-4-git-send-email-aik@ozlabs.ru> <1369256817.1374.29@scott-Lenovo-G560> <20130525024524.GA6112@boomeroo.fritz.box> <51A33418.40909@redhat.com> In-Reply-To: <51A33418.40909@redhat.com> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 44 On 05/27/2013 08:23 PM, Paolo Bonzini wrote: > Il 25/05/2013 04:45, David Gibson ha scritto: >>>> + case KVM_CREATE_SPAPR_TCE_IOMMU: { >>>> + struct kvm_create_spapr_tce_iommu create_tce_iommu; >>>> + struct kvm *kvm = filp->private_data; >>>> + >>>> + r = -EFAULT; >>>> + if (copy_from_user(&create_tce_iommu, argp, >>>> + sizeof(create_tce_iommu))) >>>> + goto out; >>>> + r = kvm_vm_ioctl_create_spapr_tce_iommu(kvm, >>>> &create_tce_iommu); >>>> + goto out; >>>> + } > > Would it make sense to make this the only interface for creating TCEs? > That is, pass both a window_size and an IOMMU group id (or e.g. -1 for > no hardware IOMMU usage), and have a single ioctl for both cases? > There's some duplicated code between kvm_vm_ioctl_create_spapr_tce and > kvm_vm_ioctl_create_spapr_tce_iommu. Just few bits. Is there really much sense in making one function from those two? I tried, looked a bit messy. > KVM_CREATE_SPAPR_TCE could stay for backwards-compatibility, or you > could just use a new capability and drop the old ioctl. The old capability+ioctl already exist for quite a while and few QEMU versions supporting it were released so we do not want just drop it. So then what is the benefit of having a new interface with support of both types? > I'm not sure > whether you're already considering the ABI to be stable for kvmppc. Is any bit of KVM using it? Cannot see from Documentation/ABI. -- Alexey -- 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/