From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53220C4332F for ; Wed, 11 May 2022 16:58:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345234AbiEKQ6d (ORCPT ); Wed, 11 May 2022 12:58:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233678AbiEKQ6b (ORCPT ); Wed, 11 May 2022 12:58:31 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DB6713C377; Wed, 11 May 2022 09:58:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652288310; x=1683824310; h=date:from:to:cc:subject:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=L+SbLcoPf9zuYRgUS6mcapuzb8rI2aXPD90HpmL4jgs=; b=Zs6M85aKbq3gRwBYFFZcQp+0/T4/FCaZ/zPEZ39so5DS6eD6ddLyzP13 fOVwnu6Cb8XWBPQm5Jyc2tI0tIhMSqRvbNRwTK1AC8mwugVCyv23xkco/ DP5grrASN0f1DXpIXlXfFVD7K0Uxh23Z/OphJX3U0ZSkb1M1P0J8tmbCQ mcsO0SDmwnP4/CSKoND+e9aJQLyXr3izE8kmHFx7IVQiS9einbwGQMrbJ DzE+KRmSZG/ij2RZtdcwZTMbn2RzAF0pDMWTdZiyhLkYOk0YoEpT038oW TrniUmwIiTx/2maTjg7ndeam3DvEjxqnfqWatop3azIvR9FACNSQ4XjXy w==; X-IronPort-AV: E=McAfee;i="6400,9594,10344"; a="269887278" X-IronPort-AV: E=Sophos;i="5.91,217,1647327600"; d="scan'208";a="269887278" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2022 09:58:30 -0700 X-IronPort-AV: E=Sophos;i="5.91,217,1647327600"; d="scan'208";a="520594260" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.198.157]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2022 09:58:29 -0700 Date: Wed, 11 May 2022 10:02:16 -0700 From: Jacob Pan To: Jason Gunthorpe Cc: iommu@lists.linux-foundation.org, LKML , dmaengine@vger.kernel.org, Joerg Roedel , David Woodhouse , Jean-Philippe Brucker , Lu Baolu , vkoul@kernel.org, robin.murphy@arm.com, will@kernel.org, Yi Liu , Dave Jiang , "Tian, Kevin" , Raj Ashok , Eric Auger , jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v3 1/4] iommu/vt-d: Implement domain ops for attach_dev_pasid Message-ID: <20220511100216.7615e288@jacob-builder> In-Reply-To: <20220511161237.GB49344@nvidia.com> References: <20220510210704.3539577-1-jacob.jun.pan@linux.intel.com> <20220510210704.3539577-2-jacob.jun.pan@linux.intel.com> <20220510232121.GP49344@nvidia.com> <20220510172309.3c4e7512@jacob-builder> <20220511115427.GU49344@nvidia.com> <20220511082958.79d5d8ee@jacob-builder> <20220511161237.GB49344@nvidia.com> Organization: OTC X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jason, On Wed, 11 May 2022 13:12:37 -0300, Jason Gunthorpe wrote: > On Wed, May 11, 2022 at 08:35:18AM -0700, Jacob Pan wrote: > > > > Huh? The intel driver shares the same ops between UNMANAGED and DMA - > > > and in general I do not think we should be putting special knowledge > > > about the DMA domains in the drivers. Drivers should continue to treat > > > them identically to UNMANAGED. > > > > > OK, other than SVA domain, the rest domain types share the same default > > ops. I agree that the default ops should be the same for UNMANAGED, > > IDENTITY, and DMA domain types. Minor detail is that we need to treat > > IDENTITY domain slightly different when it comes down to PASID entry > > programming. > > I would be happy if IDENTITY had its own ops, if that makes sense > I have tried to have its own ops but there are complications around checking if a domain has ops. It would be a logic thing to clean up next. > > If not global, perhaps we could have a list of pasids (e.g. xarray) > > attached to the device_domain_info. The TLB flush logic would just go > > through the list w/o caring what the PASIDs are for. Does it make sense > > to you? > > Sort of, but we shouldn't duplicate xarrays - the group already has > this xarray - need to find some way to allow access to it from the > driver. > I am not following, here are the PASIDs for devTLB flush which is per device. Why group? We could retrieve PASIDs from the device PASID table but xa would be more efficient. > > > > Are you suggesting the dma-iommu API should be called > > > > iommu_set_dma_pasid instead of iommu_attach_dma_pasid? > > > > > > No that API is Ok - the driver ops API should be 'set' not > > > attach/detach > > Sounds good, this operation has little in common with > > domain_ops.dev_attach_pasid() used by SVA domain. So I will add a new > > domain_ops.dev_set_pasid() > > What? No, their should only be one operation, 'dev_set_pasid' and it > is exactly the same as the SVA operation. It configures things so that > any existing translation on the PASID is removed and the PASID > translates according to the given domain. > > SVA given domain or UNMANAGED given domain doesn't matter to the > higher level code. The driver should implement per-domain ops as > required to get the different behaviors. Perhaps some code to clarify, we have sva_domain_ops.dev_attach_pasid() = intel_svm_attach_dev_pasid; default_domain_ops.dev_attach_pasid() = intel_iommu_attach_dev_pasid; Consolidate pasid programming into dev_set_pasid() then called by both intel_svm_attach_dev_pasid() and intel_iommu_attach_dev_pasid(), right? Thanks, Jacob