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=-10.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 2120EC32753 for ; Wed, 14 Aug 2019 18:04:53 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0469F2084F for ; Wed, 14 Aug 2019 18:04:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0469F2084F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id E8913E2D; Wed, 14 Aug 2019 18:04:12 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 551DDDD8 for ; Wed, 14 Aug 2019 18:04:08 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id C0F9389D for ; Wed, 14 Aug 2019 18:04:07 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D74321570; Wed, 14 Aug 2019 10:56:45 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D4B3A3F694; Wed, 14 Aug 2019 10:56:43 -0700 (PDT) From: Will Deacon To: iommu@lists.linux-foundation.org Subject: [PATCH 02/13] iommu/io-pgtable-arm: Remove redundant call to io_pgtable_tlb_sync() Date: Wed, 14 Aug 2019 18:56:23 +0100 Message-Id: <20190814175634.21081-3-will@kernel.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190814175634.21081-1-will@kernel.org> References: <20190814175634.21081-1-will@kernel.org> Cc: Jean-Philippe Brucker , Vijay Kilary , Robin Murphy , Jan Glauber , Alex Williamson , Jayachandran Chandrasekharan Nair , Jon Masters , David Woodhouse , Will Deacon X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Commit b6b65ca20bc9 ("iommu/io-pgtable-arm: Add support for non-strict mode") added an unconditional call to io_pgtable_tlb_sync() immediately after the case where we replace a block entry with a table entry during an unmap() call. This is redundant, since the IOMMU API will call iommu_tlb_sync() on this path and the patch in question mentions this: | To save having to reason about it too much, make sure the invalidation | in arm_lpae_split_blk_unmap() just performs its own unconditional sync | to minimise the window in which we're technically violating the break- | before-make requirement on a live mapping. This might work out redundant | with an outer-level sync for strict unmaps, but we'll never be splitting | blocks on a DMA fastpath anyway. However, this sync gets in the way of deferred TLB invalidation for leaf entries and is at best a questionable, unproven hack. Remove it. Signed-off-by: Will Deacon --- drivers/iommu/io-pgtable-arm-v7s.c | 1 - drivers/iommu/io-pgtable-arm.c | 1 - 2 files changed, 2 deletions(-) diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c index 0fc8dfab2abf..a62733c6a632 100644 --- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -587,7 +587,6 @@ static size_t arm_v7s_split_blk_unmap(struct arm_v7s_io_pgtable *data, } io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true); - io_pgtable_tlb_sync(&data->iop); return size; } diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 161a7d56264d..0d6633921c1e 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -583,7 +583,6 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data, tablep = iopte_deref(pte, data); } else if (unmap_idx >= 0) { io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true); - io_pgtable_tlb_sync(&data->iop); return size; } -- 2.11.0 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu