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 X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAD69C433E6 for ; Tue, 9 Feb 2021 12:11:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88A1B64E70 for ; Tue, 9 Feb 2021 12:11:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230006AbhBIMLH (ORCPT ); Tue, 9 Feb 2021 07:11:07 -0500 Received: from mga03.intel.com ([134.134.136.65]:2684 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229719AbhBIMKA (ORCPT ); Tue, 9 Feb 2021 07:10:00 -0500 IronPort-SDR: xagN38vN6YCwwHcRN9pVmg1E7rvUECPcCWbwaHjohs1uRhpgPMtoJcnPBrJe5ZWD5dllMyoRHz 0IeIc3SXHyKg== X-IronPort-AV: E=McAfee;i="6000,8403,9889"; a="181931417" X-IronPort-AV: E=Sophos;i="5.81,164,1610438400"; d="scan'208";a="181931417" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Feb 2021 04:08:04 -0800 IronPort-SDR: EkElaaO7PCIBA7u/r7+YS4trpQvRbTAKGLXQ9dXFuJaQMYuagqKw+/nG+EKN+fuOkgJwNMxnEj bFzIa3t3AiOA== X-IronPort-AV: E=Sophos;i="5.81,164,1610438400"; d="scan'208";a="396095446" Received: from yisun1-ubuntu.bj.intel.com (HELO yi.y.sun) ([10.238.156.116]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-SHA256; 09 Feb 2021 04:07:59 -0800 Date: Tue, 9 Feb 2021 20:02:31 +0800 From: Yi Sun To: Robin Murphy Cc: Keqian Zhu , Mark Rutland , kvm@vger.kernel.org, Catalin Marinas , Kirti Wankhede , Will Deacon , kvmarm@lists.cs.columbia.edu, Marc Zyngier , jiangkunkun@huawei.com, wanghaibin.wang@huawei.com, kevin.tian@intel.com, yan.y.zhao@intel.com, Suzuki K Poulose , Alex Williamson , linux-arm-kernel@lists.infradead.org, Cornelia Huck , linux-kernel@vger.kernel.org, lushenming@huawei.com, iommu@lists.linux-foundation.org, James Morse Subject: Re: [RFC PATCH 10/11] vfio/iommu_type1: Optimize dirty bitmap population based on iommu HWDBM Message-ID: <20210209120231.GC28580@yi.y.sun> References: <20210128151742.18840-1-zhukeqian1@huawei.com> <20210128151742.18840-11-zhukeqian1@huawei.com> <20210207095630.GA28580@yi.y.sun> <8150bd3a-dbb9-2e2b-386b-04e66f4b68dc@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8150bd3a-dbb9-2e2b-386b-04e66f4b68dc@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 21-02-09 11:16:08, Robin Murphy wrote: > On 2021-02-07 09:56, Yi Sun wrote: > >Hi, > > > >On 21-01-28 23:17:41, Keqian Zhu wrote: > > > >[...] > > > >>+static void vfio_dma_dirty_log_start(struct vfio_iommu *iommu, > >>+ struct vfio_dma *dma) > >>+{ > >>+ struct vfio_domain *d; > >>+ > >>+ list_for_each_entry(d, &iommu->domain_list, next) { > >>+ /* Go through all domain anyway even if we fail */ > >>+ iommu_split_block(d->domain, dma->iova, dma->size); > >>+ } > >>+} > > > >This should be a switch to prepare for dirty log start. Per Intel > >Vtd spec, there is SLADE defined in Scalable-Mode PASID Table Entry. > >It enables Accessed/Dirty Flags in second-level paging entries. > >So, a generic iommu interface here is better. For Intel iommu, it > >enables SLADE. For ARM, it splits block. > > From a quick look, VT-D's SLADE and SMMU's HTTU appear to be the > exact same thing. This step isn't about enabling or disabling that > feature itself (the proposal for SMMU is to simply leave HTTU > enabled all the time), it's about controlling the granularity at > which the dirty status can be detected/reported at all, since that's > tied to the pagetable structure. > > However, if an IOMMU were to come along with some other way of > reporting dirty status that didn't depend on the granularity of > individual mappings, then indeed it wouldn't need this operation. > Per my thought, we can use these two start/stop interfaces to make user space decide when to start/stop the dirty tracking. For Intel SLADE, I think we can enable this bit when this start interface is called by user space. I don't think leave SLADE enabled all the time is necessary for Intel Vt-d. So I suggest a generic interface here. Thanks! > Robin. > > >>+ > >>+static void vfio_dma_dirty_log_stop(struct vfio_iommu *iommu, > >>+ struct vfio_dma *dma) > >>+{ > >>+ struct vfio_domain *d; > >>+ > >>+ list_for_each_entry(d, &iommu->domain_list, next) { > >>+ /* Go through all domain anyway even if we fail */ > >>+ iommu_merge_page(d->domain, dma->iova, dma->size, > >>+ d->prot | dma->prot); > >>+ } > >>+} > > > >Same as above comment, a generic interface is required here. > > > >>+ > >>+static void vfio_iommu_dirty_log_switch(struct vfio_iommu *iommu, bool start) > >>+{ > >>+ struct rb_node *n; > >>+ > >>+ /* Split and merge even if all iommu don't support HWDBM now */ > >>+ for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) { > >>+ struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > >>+ > >>+ if (!dma->iommu_mapped) > >>+ continue; > >>+ > >>+ /* Go through all dma range anyway even if we fail */ > >>+ if (start) > >>+ vfio_dma_dirty_log_start(iommu, dma); > >>+ else > >>+ vfio_dma_dirty_log_stop(iommu, dma); > >>+ } > >>+} > >>+ > >> static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > >> unsigned long arg) > >> { > >>@@ -2812,8 +2900,10 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > >> pgsize = 1 << __ffs(iommu->pgsize_bitmap); > >> if (!iommu->dirty_page_tracking) { > >> ret = vfio_dma_bitmap_alloc_all(iommu, pgsize); > >>- if (!ret) > >>+ if (!ret) { > >> iommu->dirty_page_tracking = true; > >>+ vfio_iommu_dirty_log_switch(iommu, true); > >>+ } > >> } > >> mutex_unlock(&iommu->lock); > >> return ret; > >>@@ -2822,6 +2912,7 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > >> if (iommu->dirty_page_tracking) { > >> iommu->dirty_page_tracking = false; > >> vfio_dma_bitmap_free_all(iommu); > >>+ vfio_iommu_dirty_log_switch(iommu, false); > >> } > >> mutex_unlock(&iommu->lock); > >> return 0; > >>-- > >>2.19.1 > >_______________________________________________ > >iommu mailing list > >iommu@lists.linux-foundation.org > >https://lists.linuxfoundation.org/mailman/listinfo/iommu > >