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 4277FC6FA99 for ; Fri, 10 Mar 2023 05:10:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230071AbjCJFKS (ORCPT ); Fri, 10 Mar 2023 00:10:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230161AbjCJFJx (ORCPT ); Fri, 10 Mar 2023 00:09:53 -0500 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 935E6107D7B; Thu, 9 Mar 2023 21:09:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678424944; x=1709960944; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=+J49aPyhvpQwkShbD0yDrpi5G/X/Mfrh2uMgIT+15TA=; b=JTaGs5tZIqGmZ44KXYM7TXLUfhZZ+3OKBt+tQDqYq6uDJKKNLBSP9iuw yoy+wKmwBWaGxNc/Y1moUloMIboS4WLA9FJQ9Hfe0rMpvZpzcQFpc2C11 ARIx40DMf9g78gvF6fHHsWpRSibFA3PBrBxsrfvlGkrbWINAwMVPNteBW PO2DPro1U32vDB+quZD+xREqVQUJlDLTGpLSduugg9fG3A89vJCf7G03J VXB/ys9LiQGtCdffh7lFhqpYqfuVrIdWzNVXpxf8LXjo3fzNhV8eMteLU CTbbkuhb2qYAYx32qV45ttMflzD5TvdlqHMgIanFX+FlnGzn2pmCtGsly w==; X-IronPort-AV: E=McAfee;i="6500,9779,10644"; a="335345582" X-IronPort-AV: E=Sophos;i="5.98,248,1673942400"; d="scan'208";a="335345582" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Mar 2023 21:08:57 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10644"; a="741826265" X-IronPort-AV: E=Sophos;i="5.98,248,1673942400"; d="scan'208";a="741826265" Received: from allen-box.sh.intel.com (HELO [10.239.159.48]) ([10.239.159.48]) by fmsmga008.fm.intel.com with ESMTP; 09 Mar 2023 21:08:51 -0800 Message-ID: <69753e4a-32f3-8760-ba1d-8286badd159e@linux.intel.com> Date: Fri, 10 Mar 2023 13:07:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Cc: baolu.lu@linux.intel.com, Robin Murphy , Will Deacon , David Woodhouse , Raj Ashok , "Tian, Kevin" , Yi Liu , "Yu, Fenghua" , Dave Jiang , Kirill Shutemov , Tony Luck Subject: Re: [PATCH v5 4/7] iommu/sva: Stop using ioasid_set for SVA Content-Language: en-US To: Jacob Pan , LKML , iommu@lists.linux.dev, Jason Gunthorpe , Joerg Roedel , Jean-Philippe Brucker , Dave Hansen , Thomas Gleixner , X86 Kernel , bp@alien8.de, "H. Peter Anvin" , Peter Zijlstra , corbet@lwn.net, vkoul@kernel.org, dmaengine@vger.kernel.org, linux-doc@vger.kernel.org References: <20230309222159.487826-1-jacob.jun.pan@linux.intel.com> <20230309222159.487826-6-jacob.jun.pan@linux.intel.com> From: Baolu Lu In-Reply-To: <20230309222159.487826-6-jacob.jun.pan@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 3/10/23 6:21 AM, Jacob Pan wrote: > From: Jason Gunthorpe > > Instead SVA drivers can use a simple global IDA to allocate PASIDs for > each mm_struct. > > Future work would be to allow drivers using the SVA APIs to reserve global > PASIDs from this IDA for their internal use, eg with the DMA API PASID > support. > > Signed-off-by: Jason Gunthorpe > Signed-off-by: Jacob Pan > --- > v5: > - Put removing iommu_sva_find() to a separate patch (Kevin) > - Make pasid allocation range to be inclusive (Tina) > - Simplified return code handling (Baolu) > v4: > - Keep GFP_ATOMIC flag for PASID allocation, will changed to > GFP_KERNEL in a separate patch. > --- > drivers/iommu/iommu-sva.c | 42 +++++++++++++-------------------------- > drivers/iommu/iommu-sva.h | 2 -- > 2 files changed, 14 insertions(+), 30 deletions(-) > > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c > index 4f357ef14f04..b75711bdbe97 100644 > --- a/drivers/iommu/iommu-sva.c > +++ b/drivers/iommu/iommu-sva.c > @@ -9,47 +9,33 @@ > #include "iommu-sva.h" > > static DEFINE_MUTEX(iommu_sva_lock); > -static DECLARE_IOASID_SET(iommu_sva_pasid); > +static DEFINE_IDA(iommu_global_pasid_ida); > > -/** > - * iommu_sva_alloc_pasid - Allocate a PASID for the mm > - * @mm: the mm > - * @min: minimum PASID value (inclusive) > - * @max: maximum PASID value (inclusive) > - * > - * Try to allocate a PASID for this mm, or take a reference to the existing one > - * provided it fits within the [@min, @max] range. On success the PASID is > - * available in mm->pasid and will be available for the lifetime of the mm. > - * > - * Returns 0 on success and < 0 on error. > - */ > -int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) > +static int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) > { > int ret = 0; > - ioasid_t pasid; > > - if (min == INVALID_IOASID || max == INVALID_IOASID || > - min == 0 || max < min) > + if (!pasid_valid(min) || !pasid_valid(max) || > + min == 0 || max < min) No need to change above line. > return -EINVAL; > > mutex_lock(&iommu_sva_lock); > /* Is a PASID already associated with this mm? */ > if (pasid_valid(mm->pasid)) { > - if (mm->pasid < min || mm->pasid >= max) > + if (mm->pasid < min || mm->pasid > max) I forgot why do we need to change above line. But it's better to put some comments there so that people don't need to dive into ioasid_alloc() to know the inclusion or exclusion of @min or @max. > ret = -EOVERFLOW; > goto out; > } > > - pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm); > - if (!pasid_valid(pasid)) > - ret = -ENOMEM; > - else > - mm->pasid = pasid; > + ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_ATOMIC); > + if (ret < 0) > + goto out; > + mm->pasid = ret; > + ret = 0; > out: > mutex_unlock(&iommu_sva_lock); > return ret; > } > -EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid); > > /** > * iommu_sva_bind_device() - Bind a process address space to a device > @@ -221,8 +207,8 @@ iommu_sva_handle_iopf(struct iommu_fault *fault, void *data) > > void mm_pasid_drop(struct mm_struct *mm) > { > - if (pasid_valid(mm->pasid)) { > - ioasid_free(mm->pasid); > - mm->pasid = INVALID_IOASID; > - } > + if (likely(!pasid_valid(mm->pasid))) > + return; > + > + ida_free(&iommu_global_pasid_ida, mm->pasid); Any reason why do you drop "mm->pasid = INVALID_IOASID;" here? > } > diff --git a/drivers/iommu/iommu-sva.h b/drivers/iommu/iommu-sva.h > index 102eae1817a2..c22d0174ad61 100644 > --- a/drivers/iommu/iommu-sva.h > +++ b/drivers/iommu/iommu-sva.h > @@ -8,8 +8,6 @@ > #include > #include > > -int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max); > - > /* I/O Page fault */ > struct device; > struct iommu_fault; Best regards, baolu