Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934155AbcKJPSx (ORCPT ); Thu, 10 Nov 2016 10:18:53 -0500 Received: from 8bytes.org ([81.169.241.247]:60195 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933991AbcKJPSv (ORCPT ); Thu, 10 Nov 2016 10:18:51 -0500 Date: Thu, 10 Nov 2016 16:18:48 +0100 From: Joerg Roedel To: Robin Murphy Cc: Don Dutile , Will Deacon , Alex Williamson , Christoffer Dall , Eric Auger , eric.auger.pro@gmail.com, marc.zyngier@arm.com, tglx@linutronix.de, jason@lakedaemon.net, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, drjones@redhat.com, linux-kernel@vger.kernel.org, pranav.sawargaonkar@gmail.com, iommu@lists.linux-foundation.org, punit.agrawal@arm.com, diana.craciun@nxp.com, benh@kernel.crashing.org, arnd@arndb.de, jcm@redhat.com, dwmw@amazon.co.uk Subject: Re: Summary of LPC guest MSI discussion in Santa Fe Message-ID: <20161110151848.GE2078@8bytes.org> References: <1478209178-3009-1-git-send-email-eric.auger@redhat.com> <20161103220205.37715b49@t450s.home> <20161108024559.GA20591@arm.com> <20161108202922.GC15676@cbox> <20161108163508.1bcae0c2@t450s.home> <58228F71.6020108@redhat.com> <20161109170326.GG17771@arm.com> <582371FB.2040808@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 714 Lines: 16 On Wed, Nov 09, 2016 at 08:11:16PM +0000, Robin Murphy wrote: > When we *are* in full control of the IOVA space, we just carve out what > we can find as best we can - see iova_reserve_pci_windows() in > dma-iommu.c, which isn't really all that different to what x86 does > (e.g. init_reserved_iova_ranges() in amd-iommu.c). Yeah, that code was actually written with a look at what the Intel driver does. I don't really like that it goes over all resources and reserves them individually (not only because it is not hotplug-safe). I have to check whether there is a nice and generic way to find out the root-bridge windows and just reserve them in the iova-space. That would be easier and more reliable. Joerg