From 50ecd96a28f712f8b682c0441f4cb9b086d28816 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 2 Mar 2026 18:22:53 -0400 Subject: iommupt: Fix short gather if the unmap goes into a large mapping commit ee6e69d032550687a3422504bfca3f834c7b5061 upstream. unmap has the odd behavior that it can unmap more than requested if the ending point lands within the middle of a large or contiguous IOPTE. In this case the gather should flush everything unmapped which can be larger than what was requested to be unmapped. The gather was only flushing the range requested to be unmapped, not extending to the extra range, resulting in a short invalidation if the caller hits this special condition. This was found by the new invalidation/gather test I am adding in preparation for ARMv8. Claude deduced the root cause. As far as I remember nothing relies on unmapping a large entry, so this is likely not a triggerable bug. Cc: stable@vger.kernel.org Fixes: 7c53f4238aa8 ("iommupt: Add unmap_pages op") Signed-off-by: Jason Gunthorpe Reviewed-by: Lu Baolu Reviewed-by: Samiullah Khawaja Reviewed-by: Vasant Hegde Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/generic_pt/iommu_pt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/generic_pt/iommu_pt.h b/drivers/iommu/generic_pt/iommu_pt.h index 3e33fe64feab..7e7a6e7abdee 100644 --- a/drivers/iommu/generic_pt/iommu_pt.h +++ b/drivers/iommu/generic_pt/iommu_pt.h @@ -1057,7 +1057,7 @@ size_t DOMAIN_NS(unmap_pages)(struct iommu_domain *domain, unsigned long iova, pt_walk_range(&range, __unmap_range, &unmap); - gather_range_pages(iotlb_gather, iommu_table, iova, len, + gather_range_pages(iotlb_gather, iommu_table, iova, unmap.unmapped, &unmap.free_list); return unmap.unmapped; -- cgit v1.2.3