Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751793Ab3FVX27 (ORCPT ); Sat, 22 Jun 2013 19:28:59 -0400 Received: from gate.crashing.org ([63.228.1.57]:39415 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750943Ab3FVX25 (ORCPT ); Sat, 22 Jun 2013 19:28:57 -0400 Message-ID: <1371943693.3944.104.camel@pasglop> Subject: Re: [PATCH 3/4] KVM: PPC: Add support for IOMMU in-kernel handling From: Benjamin Herrenschmidt To: David Gibson Cc: Alex Williamson , Alexey Kardashevskiy , Alexander Graf , linuxppc-dev@lists.ozlabs.org, Paul Mackerras , "kvm@vger.kernel.org mailing list" , open list , kvm-ppc@vger.kernel.org, Rusty Russell , Joerg Roedel Date: Sun, 23 Jun 2013 09:28:13 +1000 In-Reply-To: <20130622120304.GB25265@voom.fritz.box> References: <87txkun568.fsf@rustcorp.com.au> <1371617970.21896.232.camel@pasglop> <1371653443.21896.291.camel@pasglop> <1371656989.22659.98.camel@ul30vt.home> <51C28BEA.8050501@ozlabs.ru> <20130620052822.GB3140@voom.redhat.com> <1371714449.3944.14.camel@pasglop> <51C2C1CC.9000003@ozlabs.ru> <1371740113.32709.22.camel@ul30vt.home> <20130622120304.GB25265@voom.fritz.box> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1285 Lines: 29 On Sat, 2013-06-22 at 22:03 +1000, David Gibson wrote: > I think the interface should not take the group fd, but the container > fd. Holding a reference to *that* would keep the necessary things > around. But more to the point, it's the right thing semantically: > > The container is essentially the handle on a host iommu address space, > and so that's what should be bound by the KVM call to a particular > guest iommu address space. e.g. it would make no sense to bind two > different groups to different guest iommu address spaces, if they were > in the same container - the guest thinks they are different spaces, > but if they're in the same container they must be the same space. Interestingly, how are we going to extend that when/if we implement DDW ? DDW means an API by which the guest can request the creation of additional iommus for a given device (typically, in addition to the default smallish 32-bit one using 4k pages, the guest can request a larger window in 64-bit space using a larger page size). Cheers, Ben. -- 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/