From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f196.google.com ([209.85.192.196]:35095 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751680AbdGIDQA (ORCPT ); Sat, 8 Jul 2017 23:16:00 -0400 Subject: Re: Support SVM without PASID To: Alex Williamson References: <20170708140257.2de02d63@w520.home> Cc: iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-pci@vger.kernel.org, jean-Philippe Brucker , tianyu.lan@intel.com, kevin.tian@intel.com, jacob.jun.pan@intel.com From: valmiki Message-ID: <73619426-6fcc-21ce-cfd4-8c66bde63f9a@gmail.com> Date: Sun, 9 Jul 2017 08:45:57 +0530 MIME-Version: 1.0 In-Reply-To: <20170708140257.2de02d63@w520.home> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: >> Hi, >> >> In SMMUv3 architecture document i see "PASIDs are optional, >> configurable, and of a size determined by the minimum >> of the endpoint". >> >> So if PASID's are optional and not supported by PCIe end point, how SVM >> can be achieved ? > > It cannot be inferred from that statement that PASID support is not > required for SVM. AIUI, SVM is a software feature enabled by numerous > "optional" hardware features, including PASID. Features that are > optional per the hardware specification may be required for specific > software features. Thanks, > Thanks for the information Alex. Suppose if an End point doesn't support PASID, is it still possible to achieve SVM ? Are there any such features in SMMUv3 with which we can achieve it ? Regards, valmki