From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934371AbcKJPqK (ORCPT ); Thu, 10 Nov 2016 10:46:10 -0500 Received: from 8bytes.org ([81.169.241.247]:60580 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933981AbcKJPqI (ORCPT ); Thu, 10 Nov 2016 10:46:08 -0500 Date: Thu, 10 Nov 2016 16:46:06 +0100 From: Joerg Roedel To: Eric Auger Cc: eric.auger.pro@gmail.com, christoffer.dall@linaro.org, marc.zyngier@arm.com, robin.murphy@arm.com, alex.williamson@redhat.com, will.deacon@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 Subject: Re: [RFC v2 8/8] iommu/arm-smmu: implement add_reserved_regions callback Message-ID: <20161110154606.GH2078@8bytes.org> References: <1478258646-3117-1-git-send-email-eric.auger@redhat.com> <1478258646-3117-9-git-send-email-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1478258646-3117-9-git-send-email-eric.auger@redhat.com> 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 On Fri, Nov 04, 2016 at 11:24:06AM +0000, Eric Auger wrote: > The function populates the list of reserved regions with the > PCI host bridge windows and the MSI IOVA range. > > At the moment an arbitray MSI IOVA window is set at 0x8000000 > of size 1MB. > > Signed-off-by: Eric Auger > > --- > > RFC v1 -> v2: use defines for MSI IOVA base and length > --- > drivers/iommu/arm-smmu.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 66 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index c841eb7..c07ea41 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -278,6 +278,9 @@ enum arm_smmu_s2cr_privcfg { > > #define FSYNR0_WNR (1 << 4) > > +#define MSI_IOVA_BASE 0x8000000 > +#define MSI_IOVA_LENGTH 0x100000 > + > static int force_stage; > module_param(force_stage, int, S_IRUGO); > MODULE_PARM_DESC(force_stage, > @@ -1533,6 +1536,68 @@ static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args) > return iommu_fwspec_add_ids(dev, &fwid, 1); > } > > +static int add_pci_window_reserved_regions(struct iommu_domain *domain, > + struct pci_dev *dev) > +{ > + struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus); > + struct iommu_reserved_region *region; > + struct resource_entry *window; > + phys_addr_t start; > + size_t length; > + > + resource_list_for_each_entry(window, &bridge->windows) { > + if (resource_type(window->res) != IORESOURCE_MEM && > + resource_type(window->res) != IORESOURCE_IO) > + continue; Why do you care about IO resources? > + > + start = window->res->start - window->offset; > + length = window->res->end - window->res->start + 1; > + > + iommu_reserved_region_for_each(region, domain) { > + if (region->start == start && region->length == length) > + continue; > + } > + region = kzalloc(sizeof(*region), GFP_KERNEL); > + if (!region) > + return -ENOMEM; > + > + region->start = start; > + region->length = length; > + > + list_add_tail(®ion->list, &domain->reserved_regions); > + } > + return 0; > +} > + > +static int arm_smmu_add_reserved_regions(struct iommu_domain *domain, > + struct device *device) > +{ > + struct iommu_reserved_region *region; > + int ret = 0; > + > + /* An arbitrary 1MB region starting at 0x8000000 is reserved for MSIs */ > + if (!domain->iova_cookie) { > + > + region = kzalloc(sizeof(*region), GFP_KERNEL); > + if (!region) > + return -ENOMEM; > + > + region->start = MSI_IOVA_BASE; > + region->length = MSI_IOVA_LENGTH; > + list_add_tail(®ion->list, &domain->reserved_regions); > + > + ret = iommu_get_dma_msi_region_cookie(domain, > + region->start, region->length); > + if (ret) > + return ret; Gah, I hate this. Is there no other and simpler way to get the MSI region than allocating an iova-domain? In that regard, I also _hate_ the patch before introducing this weird iommu_get_dma_msi_region_cookie() function. Allocation an iova-domain is pretty expensive, as it also includes per-cpu data-structures and all, so please don't do this just for the purpose of compiling a list of reserved regions. Joerg