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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 5142EC282CE for ; Thu, 11 Apr 2019 18:49:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FD0120663 for ; Thu, 11 Apr 2019 18:49:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="eQ4Yac+o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726954AbfDKStQ (ORCPT ); Thu, 11 Apr 2019 14:49:16 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:45813 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726931AbfDKStN (ORCPT ); Thu, 11 Apr 2019 14:49:13 -0400 Received: by mail-ed1-f66.google.com with SMTP id o26so6113049edv.12 for ; Thu, 11 Apr 2019 11:49:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lX2MVOfiam4gxtJM5rz0M+xQIQGKu992FM3+lagPerc=; b=eQ4Yac+opjGEBMpNwcIhE+BWp72NvMbMpxtmojUTpE9/rOYjMILcbpoRJOSkm78WBk Aff06hpFM7720IPoJiqJyT63C+/E8qw6EX81NozIpVIX1tteropdJH6LFlD3Eh/+bnxp TqdoMoiwgIxQtWMiOGAc90uv+qOUf34JAI/T0ybJD/E7UmC1cFWzDvL9PTwU99FOa2Cq uBtmAEg9IcB2Z+rtiVJG0Mt+tgtzmiJ3TreKGg24TfCmsdd0CwQJXJinK6O+48LvF5v/ TMCo/yA7WVatb4O5GCP0DxBkXEFa1ZseoyB+vX5EoAJETdaxDHDXc+uPIuWnEbhC9q2H SvUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=lX2MVOfiam4gxtJM5rz0M+xQIQGKu992FM3+lagPerc=; b=JYUs+PAnwKD9cNyiKHmKNm6EH4tABXjPLBY1WQp3mfKikWYVE3I9e3gHPFOliTEd2G qnaUfBK/NXQy5KK6FpbSRPSkbrSPTflgTIC7RxgoPyU7DZGwPEywX6/djjf1fig1pEBq SePf0Do05EYgEWIAQMKBxV8P5buTvm/K1WyY5n/TGF3cp6xUkLXl3WDsUZOv6T8MkwvI RzNB7NbeOrZo6vza2t9iir2dFOgFI2QaMRbv/Oc4OYuNNugKok0dGtRc22GtaD1jHQ08 3eVaT7g4UfFTUna42gBAC3t2rlCDKAM47VwH+zJpYdiILFsVol2yRJRz5oWcBh93SZcM eJaw== X-Gm-Message-State: APjAAAXGiOE3Jse7bFHZp1pb7EOIRF8u6XOKpq7dpsFpD1Ag4mS7iQIi J7MFMyRyzThDvZAcSJc6Hxv/Aw== X-Google-Smtp-Source: APXvYqw1ZpBKkZJS1pdF6BGZGDt7JAfIqiI9pMC84S3fxuGG7Kvy3jG4mkJy+S81q/cfVwljARoScw== X-Received: by 2002:aa7:d954:: with SMTP id l20mr32634023eds.156.1555008551931; Thu, 11 Apr 2019 11:49:11 -0700 (PDT) Received: from localhost.localdomain ([80.233.32.123]) by smtp.gmail.com with ESMTPSA id b10sm1285130edi.28.2019.04.11.11.49.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Apr 2019 11:49:11 -0700 (PDT) From: Tom Murphy To: iommu@lists.linux-foundation.org Cc: dima@arista.com, jamessewart@arista.com, murphyt7@tcd.ie, Tom Murphy , Joerg Roedel , Will Deacon , Robin Murphy , Marek Szyprowski , Kukjin Kim , Krzysztof Kozlowski , Matthias Brugger , Andy Gross , David Brown , Rob Clark , Heiko Stuebner , Marc Zyngier , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-rockchip@lists.infradead.org Subject: [PATCH 6/9] iommu/amd: Implement map_atomic Date: Thu, 11 Apr 2019 19:47:35 +0100 Message-Id: <20190411184741.27540-7-tmurphy@arista.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190411184741.27540-1-tmurphy@arista.com> References: <20190411184741.27540-1-tmurphy@arista.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instead of using a spin lock I removed the mutex lock from both the amd_iommu_map and amd_iommu_unmap path as well. iommu_map doesn’t lock while mapping and so if iommu_map is called by two different threads on the same iova region it results in a race condition even with the locks. So the locking in amd_iommu_map and amd_iommu_unmap doesn't add any real protection. The solution to this is for whatever manages the allocated iova’s externally to make sure iommu_map isn’t called twice on the same region at the same time. Signed-off-by: Tom Murphy --- drivers/iommu/amd_iommu.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 2d4ee10626b4..b45e0e033adc 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -3089,12 +3089,12 @@ static int amd_iommu_attach_device(struct iommu_domain *dom, return ret; } -static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, - phys_addr_t paddr, size_t page_size, int iommu_prot) +static int __amd_iommu_map(struct iommu_domain *dom, unsigned long iova, + phys_addr_t paddr, size_t page_size, int iommu_prot, + gfp_t gfp) { struct protection_domain *domain = to_pdomain(dom); int prot = 0; - int ret; if (domain->mode == PAGE_MODE_NONE) return -EINVAL; @@ -3104,11 +3104,21 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, if (iommu_prot & IOMMU_WRITE) prot |= IOMMU_PROT_IW; - mutex_lock(&domain->api_lock); - ret = iommu_map_page(domain, iova, paddr, page_size, prot, GFP_KERNEL); - mutex_unlock(&domain->api_lock); + return iommu_map_page(domain, iova, paddr, page_size, prot, gfp); +} - return ret; +static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova, + phys_addr_t paddr, size_t page_size, int iommu_prot) +{ + return __amd_iommu_map(dom, iova, paddr, page_size, iommu_prot, + GFP_KERNEL); +} + +static int amd_iommu_map_atomic(struct iommu_domain *dom, unsigned long iova, + phys_addr_t paddr, size_t page_size, int iommu_prot) +{ + return __amd_iommu_map(dom, iova, paddr, page_size, iommu_prot, + GFP_ATOMIC); } static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova, @@ -3262,6 +3272,7 @@ const struct iommu_ops amd_iommu_ops = { .attach_dev = amd_iommu_attach_device, .detach_dev = amd_iommu_detach_device, .map = amd_iommu_map, + .map_atomic = amd_iommu_map_atomic, .unmap = amd_iommu_unmap, .iova_to_phys = amd_iommu_iova_to_phys, .add_device = amd_iommu_add_device, -- 2.17.1