This is a note to let you know that I've just added the patch titled vfio/iommu_type1: Fix some sanity checks in detach group to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: vfio-iommu_type1-fix-some-sanity-checks-in-detach-gr.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 93ab314fcea14bb073b0430303c8fce25b14c11c Author: Keqian Zhu <zhukeqian1@xxxxxxxxxx> Date: Fri Jan 22 17:26:35 2021 +0800 vfio/iommu_type1: Fix some sanity checks in detach group [ Upstream commit 4a19f37a3dd3f29997735e61b25ddad24b8abe73 ] 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 <zhukeqian1@xxxxxxxxxx> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index bc6ba41686fa3..9cbe058a530f0 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -866,6 +866,7 @@ 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); @@ -1974,23 +1975,6 @@ 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 @@ -2088,10 +2072,10 @@ 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; @@ -2124,10 +2108,12 @@ 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); @@ -2201,7 +2187,6 @@ static void vfio_iommu_type1_release(void *iommu_data) if (iommu->external_domain) { vfio_release_domain(iommu->external_domain, true); - vfio_sanity_check_pfn_list(iommu); kfree(iommu->external_domain); }