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 62C18C00140 for ; Sun, 31 Jul 2022 13:47:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236718AbiGaNrx (ORCPT ); Sun, 31 Jul 2022 09:47:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230436AbiGaNrv (ORCPT ); Sun, 31 Jul 2022 09:47:51 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A612BEE3C for ; Sun, 31 Jul 2022 06:47:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1659275270; x=1690811270; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=G9GK/9YI1yKGfpyKC+h7PPNL75WRdhhLc2kt2Or+8ak=; b=llIWJLYl3OCetzC/GuIEzthM0+u8r9v7LvUwnf3blXzJagZUJ443Xk5f 0pjkkGctse2FHSgC0yfeAywLNJAf7Am8yXRWE7n4oakzpxVxz9joLMn8J Pi6rWAOl3gD2hp2v/o7QbgFM6+k6P4FQgTfsLSCMtErwrG5NWHKNDlIyv a5nYnSRNSvqarLRnSeLxgbVUOwhB/0ZUtT3zakjDbgg3CLFhNlMULJRXi S/davyzaPS0+QIkKLIh8ywe3yO/7DfI9F3dyE4ZGkPmHuF7Dy8nIasL17 Ghbs8vW7XcL1b/nCkR3H0ArIyP/+oiPQ8oP3XHptem56RgaxbaozbKeHP w==; X-IronPort-AV: E=McAfee;i="6400,9594,10425"; a="290204207" X-IronPort-AV: E=Sophos;i="5.93,206,1654585200"; d="scan'208";a="290204207" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2022 06:47:50 -0700 X-IronPort-AV: E=Sophos;i="5.93,206,1654585200"; d="scan'208";a="629932522" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.208.191]) ([10.254.208.191]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2022 06:47:45 -0700 Message-ID: Date: Sun, 31 Jul 2022 21:47:44 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Cc: baolu.lu@linux.intel.com, Eric Auger , Jacob jun Pan , Zhangfei Gao , Zhu Tony , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Jean-Philippe Brucker Subject: Re: [PATCH v10 10/12] iommu: Prepare IOMMU domain for IOPF Content-Language: en-US To: Yi Liu , Joerg Roedel , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj , Will Deacon , Robin Murphy , Jean-Philippe Brucker , Dave Jiang , Vinod Koul References: <20220705050710.2887204-1-baolu.lu@linux.intel.com> <20220705050710.2887204-11-baolu.lu@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/7/31 20:50, Yi Liu wrote: > On 2022/7/5 13:07, Lu Baolu wrote: >> This adds some mechanisms around the iommu_domain so that the I/O page >> fault handling framework could route a page fault to the domain and >> call the fault handler from it. >> >> Add pointers to the page fault handler and its private data in struct >> iommu_domain. The fault handler will be called with the private data >> as a parameter once a page fault is routed to the domain. Any kernel >> component which owns an iommu domain could install handler and its >> private parameter so that the page fault could be further routed and >> handled. >> >> This also prepares the SVA implementation to be the first consumer of >> the per-domain page fault handling model. The I/O page fault handler >> for SVA is copied to the SVA file with mmget_not_zero() added before >> mmap_read_lock(). >> >> Suggested-by: Jean-Philippe Brucker >> Signed-off-by: Lu Baolu >> Reviewed-by: Jean-Philippe Brucker >> Tested-by: Zhangfei Gao >> Tested-by: Tony Zhu >> --- >>   include/linux/iommu.h         |  3 ++ >>   drivers/iommu/iommu-sva-lib.h |  8 +++++ >>   drivers/iommu/io-pgfault.c    |  7 +++++ >>   drivers/iommu/iommu-sva-lib.c | 58 +++++++++++++++++++++++++++++++++++ >>   drivers/iommu/iommu.c         |  4 +++ >>   5 files changed, 80 insertions(+) >> >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index ae0cfca064e6..47610f21d451 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -105,6 +105,9 @@ struct iommu_domain { >>       unsigned long pgsize_bitmap;    /* Bitmap of page sizes in use */ >>       struct iommu_domain_geometry geometry; >>       struct iommu_dma_cookie *iova_cookie; >> +    enum iommu_page_response_code (*iopf_handler)(struct iommu_fault >> *fault, >> +                              void *data); >> +    void *fault_data; >>       union { >>           struct { >>               iommu_fault_handler_t handler; >> diff --git a/drivers/iommu/iommu-sva-lib.h >> b/drivers/iommu/iommu-sva-lib.h >> index 8909ea1094e3..1b3ace4b5863 100644 >> --- a/drivers/iommu/iommu-sva-lib.h >> +++ b/drivers/iommu/iommu-sva-lib.h >> @@ -26,6 +26,8 @@ int iopf_queue_flush_dev(struct device *dev); >>   struct iopf_queue *iopf_queue_alloc(const char *name); >>   void iopf_queue_free(struct iopf_queue *queue); >>   int iopf_queue_discard_partial(struct iopf_queue *queue); >> +enum iommu_page_response_code >> +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data); >>   #else /* CONFIG_IOMMU_SVA */ >>   static inline int iommu_queue_iopf(struct iommu_fault *fault, void >> *cookie) >> @@ -63,5 +65,11 @@ static inline int iopf_queue_discard_partial(struct >> iopf_queue *queue) >>   { >>       return -ENODEV; >>   } >> + >> +static inline enum iommu_page_response_code >> +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data) >> +{ >> +    return IOMMU_PAGE_RESP_INVALID; >> +} >>   #endif /* CONFIG_IOMMU_SVA */ >>   #endif /* _IOMMU_SVA_LIB_H */ >> diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c >> index 1df8c1dcae77..aee9e033012f 100644 >> --- a/drivers/iommu/io-pgfault.c >> +++ b/drivers/iommu/io-pgfault.c >> @@ -181,6 +181,13 @@ static void iopf_handle_group(struct work_struct >> *work) >>    * request completes, outstanding faults will have been dealt with >> by the time >>    * the PASID is freed. >>    * >> + * Any valid page fault will be eventually routed to an iommu domain >> and the >> + * page fault handler installed there will get called. The users of this >> + * handling framework should guarantee that the iommu domain could >> only be >> + * freed after the device has stopped generating page faults (or the >> iommu >> + * hardware has been set to block the page faults) and the pending >> page faults >> + * have been flushed. >> + * >>    * Return: 0 on success and <0 on error. >>    */ >>   int iommu_queue_iopf(struct iommu_fault *fault, void *cookie) >> diff --git a/drivers/iommu/iommu-sva-lib.c >> b/drivers/iommu/iommu-sva-lib.c >> index 751366980232..536d34855c74 100644 >> --- a/drivers/iommu/iommu-sva-lib.c >> +++ b/drivers/iommu/iommu-sva-lib.c >> @@ -167,3 +167,61 @@ u32 iommu_sva_get_pasid(struct iommu_sva *handle) >>       return domain->mm->pasid; >>   } >>   EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); >> + >> +/* >> + * I/O page fault handler for SVA >> + */ >> +enum iommu_page_response_code >> +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data) >> +{ >> +    vm_fault_t ret; >> +    struct vm_area_struct *vma; >> +    struct mm_struct *mm = data; >> +    unsigned int access_flags = 0; >> +    unsigned int fault_flags = FAULT_FLAG_REMOTE; >> +    struct iommu_fault_page_request *prm = &fault->prm; >> +    enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID; >> + >> +    if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)) >> +        return status; >> + >> +    if (IS_ERR_OR_NULL(mm) || !mmget_not_zero(mm)) > > is it possible to be ERR or NULL? The mm life circle should have been > guaranteed by the mmgrab() in iommu_sva_domain_alloc(). Perhaps coding > issue if it happens. :-) Updated. Thanks! Best regards, baolu