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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 558ADC433EF for ; Thu, 4 Nov 2021 12:35:55 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 108EB611EF for ; Thu, 4 Nov 2021 12:35:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 108EB611EF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id DF0244059B; Thu, 4 Nov 2021 12:35:54 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6orekg6APeO1; Thu, 4 Nov 2021 12:35:53 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 81D9840571; Thu, 4 Nov 2021 12:35:53 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5FB64C0019; Thu, 4 Nov 2021 12:35:53 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [IPv6:2605:bc80:3010::136]) by lists.linuxfoundation.org (Postfix) with ESMTP id B76D4C000E for ; Thu, 4 Nov 2021 12:35:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 99ED560886 for ; Thu, 4 Nov 2021 12:35:52 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id COEbIRHc846a for ; Thu, 4 Nov 2021 12:35:51 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp3.osuosl.org (Postfix) with ESMTP id 88E326086E for ; Thu, 4 Nov 2021 12:35:51 +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 E765E1063; Thu, 4 Nov 2021 05:35:50 -0700 (PDT) Received: from [10.57.80.217] (unknown [10.57.80.217]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5495E3F7D7; Thu, 4 Nov 2021 05:35:50 -0700 (PDT) Message-ID: <8556aafc-f006-ad25-3bd0-0664d06dcaaf@arm.com> Date: Thu, 4 Nov 2021 12:35:49 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.2.1 Subject: Re: [PATCH 03/10] dma-direct: leak memory that can't be re-encrypted Content-Language: en-GB To: Christoph Hellwig , iommu@lists.linux-foundation.org References: <20211021090611.488281-1-hch@lst.de> <20211021090611.488281-4-hch@lst.de> From: Robin Murphy In-Reply-To: <20211021090611.488281-4-hch@lst.de> Cc: David Rientjes X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2021-10-21 10:06, Christoph Hellwig wrote: > We must never unencryped memory go back into the general page pool. > So if we fail to set it back to encrypted when freeing DMA memory, leak > the memory insted and warn the user. > > Signed-off-by: Christoph Hellwig > --- > kernel/dma/direct.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index 2fef8dd401fe9..60cb75aa6778e 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -263,9 +263,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, > return ret; > > out_encrypt_pages: > - /* If memory cannot be re-encrypted, it must be leaked */ > - if (dma_set_encrypted(dev, page_address(page), size)) > + if (dma_set_encrypted(dev, page_address(page), size)) { > + pr_warn_ratelimited( > + "leaking DMA memory that can't be re-encrypted\n"); Given that this is consistent for all uses of dma_set_encrypted(), seems like it should be factored into the helper itself. Robin. > return NULL; > + } > out_unmap_pages: > if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(ret)) > vunmap(ret); > @@ -307,7 +309,11 @@ void dma_direct_free(struct device *dev, size_t size, > dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size))) > return; > > - dma_set_encrypted(dev, cpu_addr, 1 << page_order); > + if (dma_set_encrypted(dev, cpu_addr, 1 << page_order)) { > + pr_warn_ratelimited( > + "leaking DMA memory that can't be re-encrypted\n"); > + return; > + } > > if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) > vunmap(cpu_addr); > @@ -365,7 +371,11 @@ void dma_direct_free_pages(struct device *dev, size_t size, > dma_free_from_pool(dev, vaddr, size)) > return; > > - dma_set_encrypted(dev, vaddr, 1 << page_order); > + if (dma_set_encrypted(dev, vaddr, 1 << page_order)) { > + pr_warn_ratelimited( > + "leaking DMA memory that can't be re-encrypted\n"); > + return; > + } > __dma_direct_free_pages(dev, page, size); > } > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu