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Wed, 27 Jan 2021 23:46:43 +0000 (UTC) Received: from omen.home.shazbot.org (ovpn-112-255.phx2.redhat.com [10.3.112.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id E50C25C1BB; Wed, 27 Jan 2021 23:46:41 +0000 (UTC) Date: Wed, 27 Jan 2021 16:46:41 -0700 From: Alex Williamson To: Keqian Zhu Subject: Re: [PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group Message-ID: <20210127164641.36e17bf5@omen.home.shazbot.org> In-Reply-To: <20210122092635.19900-3-zhukeqian1@huawei.com> References: <20210122092635.19900-1-zhukeqian1@huawei.com> <20210122092635.19900-3-zhukeqian1@huawei.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210127_184654_068429_8F2686AE X-CRM114-Status: GOOD ( 25.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , jiangkunkun@huawei.com, kvm@vger.kernel.org, Catalin Marinas , Kirti Wankhede , Will Deacon , kvmarm@lists.cs.columbia.edu, Marc Zyngier , Joerg Roedel , Daniel Lezcano , wanghaibin.wang@huawei.com, Julien Thierry , Suzuki K Poulose , Alexios Zavras , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Cornelia Huck , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, James Morse , Andrew Morton , Robin Murphy Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 22 Jan 2021 17:26:35 +0800 Keqian Zhu wrote: > vfio_sanity_check_pfn_list() is used to check whether pfn_list and > notifier are empty when remove the external domain, so it makes a > wrong assumption that only external domain will use the pinning > interface. > > Now we apply the pfn_list check when a vfio_dma is removed and apply > the notifier check when all domains are removed. > > Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices") > Signed-off-by: Keqian Zhu > --- > drivers/vfio/vfio_iommu_type1.c | 33 ++++++++++----------------------- > 1 file changed, 10 insertions(+), 23 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 161725395f2f..d8c10f508321 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -957,6 +957,7 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma, > > static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) > { > + WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)); > vfio_unmap_unpin(iommu, dma, true); > vfio_unlink_dma(iommu, dma); > put_task_struct(dma->task); > @@ -2250,23 +2251,6 @@ static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu) > } > } > > -static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu) > -{ > - struct rb_node *n; > - > - n = rb_first(&iommu->dma_list); > - for (; n; n = rb_next(n)) { > - struct vfio_dma *dma; > - > - dma = rb_entry(n, struct vfio_dma, node); > - > - if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list))) > - break; > - } > - /* mdev vendor driver must unregister notifier */ > - WARN_ON(iommu->notifier.head); > -} > - > /* > * Called when a domain is removed in detach. It is possible that > * the removed domain decided the iova aperture window. Modify the > @@ -2366,10 +2350,10 @@ static void vfio_iommu_type1_detach_group(void *iommu_data, > kfree(group); > > if (list_empty(&iommu->external_domain->group_list)) { > - vfio_sanity_check_pfn_list(iommu); > - > - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) > + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) { > + WARN_ON(iommu->notifier.head); > vfio_iommu_unmap_unpin_all(iommu); > + } > > kfree(iommu->external_domain); > iommu->external_domain = NULL; > @@ -2403,10 +2387,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data, > */ > if (list_empty(&domain->group_list)) { > if (list_is_singular(&iommu->domain_list)) { > - if (!iommu->external_domain) > + if (!iommu->external_domain) { > + WARN_ON(iommu->notifier.head); > vfio_iommu_unmap_unpin_all(iommu); > - else > + } else { > vfio_iommu_unmap_unpin_reaccount(iommu); > + } > } > iommu_domain_free(domain->domain); > list_del(&domain->next); > @@ -2488,9 +2474,10 @@ static void vfio_iommu_type1_release(void *iommu_data) > struct vfio_iommu *iommu = iommu_data; > struct vfio_domain *domain, *domain_tmp; > > + WARN_ON(iommu->notifier.head); I don't see that this does any harm, but isn't it actually redundant? It seems vfio-core only calls the iommu backend release function after removing all the groups, so the tests in _detach_group should catch all cases. We're expecting the vfio bus/mdev driver to remove the notifier when a device is closed, which necessarily occurs before detaching the group. Thanks, Alex > + > if (iommu->external_domain) { > vfio_release_domain(iommu->external_domain, true); > - vfio_sanity_check_pfn_list(iommu); > kfree(iommu->external_domain); > } > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel