From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f70.google.com (mail-oi0-f70.google.com [209.85.218.70]) by kanga.kvack.org (Postfix) with ESMTP id BEB6E6B78CE for ; Thu, 6 Sep 2018 08:45:56 -0400 (EDT) Received: by mail-oi0-f70.google.com with SMTP id l191-v6so12466728oig.23 for ; Thu, 06 Sep 2018 05:45:56 -0700 (PDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id c188-v6si3411569oia.340.2018.09.06.05.45.55 for ; Thu, 06 Sep 2018 05:45:55 -0700 (PDT) Subject: Re: [PATCH v2 01/40] iommu: Introduce Shared Virtual Addressing API References: <20180511190641.23008-1-jean-philippe.brucker@arm.com> <20180511190641.23008-2-jean-philippe.brucker@arm.com> <03d31ba5-1eda-ea86-8c0c-91d14c86fe83@arm.com> From: Jean-Philippe Brucker Message-ID: Date: Thu, 6 Sep 2018 13:45:36 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: =?UTF-8?Q?Christian_K=c3=b6nig?= , Auger Eric , linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org Cc: xieyisheng1@huawei.com, liubo95@huawei.com, xuzaibo@huawei.com, thunder.leizhen@huawei.com, will.deacon@arm.com, okaya@codeaurora.org, yi.l.liu@intel.com, ashok.raj@intel.com, tn@semihalf.com, joro@8bytes.org, bharatku@xilinx.com, liudongdong3@huawei.com, rfranz@cavium.com, kevin.tian@intel.com, jacob.jun.pan@linux.intel.com, jcrouse@codeaurora.org, rgummal@xilinx.com, jonathan.cameron@huawei.com, shunyong.yang@hxt-semitech.com, robin.murphy@arm.com, ilias.apalodimas@linaro.org, alex.williamson@redhat.com, robdclark@gmail.com, dwmw2@infradead.org, nwatters@codeaurora.org, baolu.lu@linux.intel.com On 06/09/2018 12:12, Christian KA?nig wrote: > Am 06.09.2018 um 13:09 schrieb Jean-Philippe Brucker: >> Hi Eric, >> >> Thanks for reviewing >> >> On 05/09/2018 12:29, Auger Eric wrote: >>>> +int iommu_sva_device_init(struct device *dev, unsigned long features, >>>> +A A A A A A A A A A A A A unsigned int max_pasid) >>> what about min_pasid? >> No one asked for it... The max_pasid parameter is here for drivers that >> have vendor-specific PASID size limits, such as AMD KFD (see >> kfd_iommu_device_init and >> https://patchwork.kernel.org/patch/9989307/#21389571). But in most cases >> the PASID size will only depend on the PCI PASID capability and the >> IOMMU limits, both known by the IOMMU driver, so device drivers won't >> have to set max_pasid. >> >> IOMMU drivers need to set min_pasid in the sva_device_init callback >> because it may be either 1 (e.g. Arm where PASID #0 is reserved) or 0 >> (Intel Vt-d rev2), but at the moment I can't see a reason for device >> drivers to override min_pasid > > Sorry to ruin your day, but if I'm not completely mistaken PASID zero is > reserved in the AMD KFD as well. Heh, fair enough. I'll add the min_pasid parameter Thanks, Jean