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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 BC56FC3F2C6 for ; Tue, 3 Mar 2020 17:23:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F25B20866 for ; Tue, 3 Mar 2020 17:23:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730187AbgCCRXV (ORCPT ); Tue, 3 Mar 2020 12:23:21 -0500 Received: from foss.arm.com ([217.140.110.172]:50200 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727198AbgCCRXV (ORCPT ); Tue, 3 Mar 2020 12:23:21 -0500 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 BC5852F; Tue, 3 Mar 2020 09:23:20 -0800 (PST) Received: from [10.1.196.37] (e121345-lin.cambridge.arm.com [10.1.196.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D2C7F3F534; Tue, 3 Mar 2020 09:23:19 -0800 (PST) Subject: Re: [PATCH] iommu/dma: Fix MSI reservation allocation To: Marc Zyngier , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Joerg Roedel , Eric Auger , Will Deacon , stable@vger.kernel.org References: <20200303115154.32263-1-maz@kernel.org> From: Robin Murphy Message-ID: Date: Tue, 3 Mar 2020 17:23:14 +0000 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200303115154.32263-1-maz@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/03/2020 11:51 am, Marc Zyngier wrote: > The way cookie_init_hw_msi_region() allocates the iommu_dma_msi_page > structures doesn't match the way iommu_put_dma_cookie() frees them. > > The former performs a single allocation of all the required structures, > while the latter tries to free them one at a time. It doesn't quite > work for the main use case (the GICv3 ITS where the range is 64kB) > when the base ganule size is 4kB. > > This leads to a nice slab corruption on teardown, which is easily > observable by simply creating a VF on a SRIOV-capable device, and > tearing it down immediately (no need to even make use of it). > > Fix it by allocating iommu_dma_msi_page structures one at a time. Bleh, you know you're supposed to be using 64K pages on those things, right? :P > Fixes: 7c1b058c8b5a3 ("iommu/dma: Handle IOMMU API reserved regions") > Signed-off-by: Marc Zyngier > Cc: Robin Murphy > Cc: Joerg Roedel > Cc: Eric Auger > Cc: Will Deacon > Cc: stable@vger.kernel.org > --- > drivers/iommu/dma-iommu.c | 36 ++++++++++++++++++++++++------------ > 1 file changed, 24 insertions(+), 12 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index a2e96a5fd9a7..01fa64856c12 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -171,25 +171,37 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, > phys_addr_t start, phys_addr_t end) > { > struct iova_domain *iovad = &cookie->iovad; > - struct iommu_dma_msi_page *msi_page; > - int i, num_pages; > + struct iommu_dma_msi_page *msi_page, *tmp; > + int i, num_pages, ret = 0; > + phys_addr_t base; > > - start -= iova_offset(iovad, start); > + base = start -= iova_offset(iovad, start); > num_pages = iova_align(iovad, end - start) >> iova_shift(iovad); > > - msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL); > - if (!msi_page) > - return -ENOMEM; > - > for (i = 0; i < num_pages; i++) { > - msi_page[i].phys = start; > - msi_page[i].iova = start; > - INIT_LIST_HEAD(&msi_page[i].list); > - list_add(&msi_page[i].list, &cookie->msi_page_list); > + msi_page = kmalloc(sizeof(*msi_page), GFP_KERNEL); > + if (!msi_page) { > + ret = -ENOMEM; I think we can just return here and skip the cleanup below - by the time we get here the cookie itself has already been allocated and initialised, so even if iommu_dma_init_domain() fails someone else has already accepted the responsibility of calling iommu_put_dma_cookie() at some point later, which will clean up properly. Cheers, Robin. > + break; > + } > + msi_page->phys = start; > + msi_page->iova = start; > + INIT_LIST_HEAD(&msi_page->list); > + list_add(&msi_page->list, &cookie->msi_page_list); > start += iovad->granule; > } > > - return 0; > + if (ret) { > + list_for_each_entry_safe(msi_page, tmp, > + &cookie->msi_page_list, list) { > + if (msi_page->phys >= base && msi_page->phys < start) { > + list_del(&msi_page->list); > + kfree(msi_page); > + } > + } > + } > + > + return ret; > } > > static int iova_reserve_pci_windows(struct pci_dev *dev, >