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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham 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 AE37CCA9EBC for ; Thu, 24 Oct 2019 07:22:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8D7F520684 for ; Thu, 24 Oct 2019 07:22:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407113AbfJXHWp (ORCPT ); Thu, 24 Oct 2019 03:22:45 -0400 Received: from Mailgw01.mediatek.com ([1.203.163.78]:29526 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2390502AbfJXHWo (ORCPT ); Thu, 24 Oct 2019 03:22:44 -0400 X-UUID: c00efe6b6a6b490a8ec249bb5f663775-20191024 X-UUID: c00efe6b6a6b490a8ec249bb5f663775-20191024 Received: from mtkcas35.mediatek.inc [(172.27.4.253)] by mailgw01.mediatek.com (envelope-from ) (mailgw01.mediatek.com ESMTP with TLS) with ESMTP id 222561763; Thu, 24 Oct 2019 15:22:33 +0800 Received: from MTKCAS36.mediatek.inc (172.27.4.186) by MTKMBS31DR.mediatek.inc (172.27.6.102) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 24 Oct 2019 15:22:31 +0800 Received: from [10.17.3.153] (172.27.4.253) by MTKCAS36.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Thu, 24 Oct 2019 15:22:30 +0800 Message-ID: <1571901752.19130.135.camel@mhfsdcap03> Subject: Re: [PATCH v4 3/7] iommu/mediatek: Use gather to achieve the tlb range flush From: Yong Wu To: Will Deacon CC: Matthias Brugger , Joerg Roedel , Will Deacon , Evan Green , Robin Murphy , Tomasz Figa , , , , , , , Nicolas Boichat , , , , Date: Thu, 24 Oct 2019 15:22:32 +0800 In-Reply-To: <20191023165543.GB27471@willie-the-truck> References: <1571196792-12382-1-git-send-email-yong.wu@mediatek.com> <1571196792-12382-4-git-send-email-yong.wu@mediatek.com> <20191023165543.GB27471@willie-the-truck> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-SNTS-SMTP: B3428B34711F9D4340351C5FBF71C7D9A7707DD264962EFF9A5C5A10E427B3F82000:8 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2019-10-23 at 17:55 +0100, Will Deacon wrote: > On Wed, Oct 16, 2019 at 11:33:08AM +0800, Yong Wu wrote: > > Use the iommu_gather mechanism to achieve the tlb range flush. > > Gather the iova range in the "tlb_add_page", then flush the merged iova > > range in iotlb_sync. > > > > Suggested-by: Tomasz Figa > > Signed-off-by: Yong Wu > > --- > > drivers/iommu/mtk_iommu.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > index c2f6c78..81ac95f 100644 > > --- a/drivers/iommu/mtk_iommu.c > > +++ b/drivers/iommu/mtk_iommu.c > > @@ -245,11 +245,9 @@ static void mtk_iommu_tlb_flush_page_nosync(struct iommu_iotlb_gather *gather, > > void *cookie) > > { > > struct mtk_iommu_data *data = cookie; > > - unsigned long flags; > > + struct iommu_domain *domain = &data->m4u_dom->domain; > > > > - spin_lock_irqsave(&data->tlb_lock, flags); > > - mtk_iommu_tlb_add_flush_nosync(iova, granule, granule, true, cookie); > > - spin_unlock_irqrestore(&data->tlb_lock, flags); > > + iommu_iotlb_gather_add_page(domain, gather, iova, granule); > > You need to be careful here, because iommu_iotlb_gather_add_page() can > call iommu_tlb_sync() in some situations and you don't hold the lock. The mtk_iommu_iotlb_sync below already has the lock in it, so I delete the lock here. > > > static const struct iommu_flush_ops mtk_iommu_flush_ops = { > > @@ -469,9 +467,15 @@ static void mtk_iommu_iotlb_sync(struct iommu_domain *domain, > > struct iommu_iotlb_gather *gather) > > { > > struct mtk_iommu_data *data = mtk_iommu_get_m4u_data(); > > + size_t length = gather->end - gather->start; > > unsigned long flags; > > > > + if (gather->start == ULONG_MAX) > > + return; > > + > > spin_lock_irqsave(&data->tlb_lock, flags); > > + mtk_iommu_tlb_add_flush_nosync(gather->start, length, gather->pgsize, > > + false, data); > > mtk_iommu_tlb_sync(data); > > spin_unlock_irqrestore(&data->tlb_lock, flags); > > Modulo my comment above, this fixes my previous comment. Given that mainline > is already broken, I guess the runtime bisectability isn't a problem. As the reply in [2/7]. the mainline is not broken after [2/7], it only go to the previous status before commit(4d689b619445). After using the iommu_gather, the iova will be the merged range in this iotlb_sync, it is just fit to do the tlb-flush/tlb-sync. then it fixes our potential issue(No tlb-sync for the previous tlb-flush range). > > Will