From fa4c4507099f781ca89a748c480af9cf97629726 Mon Sep 17 00:00:00 2001 From: Niklas Schnelle Date: Thu, 28 Sep 2023 16:31:35 +0200 Subject: iommu: Allow .iotlb_sync_map to fail and handle s390's -ENOMEM return On s390 when using a paging hypervisor, .iotlb_sync_map is used to sync mappings by letting the hypervisor inspect the synced IOVA range and updating a shadow table. This however means that .iotlb_sync_map can fail as the hypervisor may run out of resources while doing the sync. This can be due to the hypervisor being unable to pin guest pages, due to a limit on mapped addresses such as vfio_iommu_type1.dma_entry_limit or lack of other resources. Either way such a failure to sync a mapping should result in a DMA_MAPPING_ERROR. Now especially when running with batched IOTLB flushes for unmap it may be that some IOVAs have already been invalidated but not yet synced via .iotlb_sync_map. Thus if the hypervisor indicates running out of resources, first do a global flush allowing the hypervisor to free resources associated with these mappings as well a retry creating the new mappings and only if that also fails report this error to callers. Reviewed-by: Lu Baolu Reviewed-by: Matthew Rosato Acked-by: Jernej Skrabec # sun50i Signed-off-by: Niklas Schnelle Link: https://lore.kernel.org/r/20230928-dma_iommu-v13-1-9e5fc4dacc36@linux.ibm.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'drivers/iommu/iommu.c') diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 1ecac2b5c54f..1cc9d139c860 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2585,8 +2585,17 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova, return -EINVAL; ret = __iommu_map(domain, iova, paddr, size, prot, gfp); - if (ret == 0 && ops->iotlb_sync_map) - ops->iotlb_sync_map(domain, iova, size); + if (ret == 0 && ops->iotlb_sync_map) { + ret = ops->iotlb_sync_map(domain, iova, size); + if (ret) + goto out_err; + } + + return ret; + +out_err: + /* undo mappings already done */ + iommu_unmap(domain, iova, size); return ret; } @@ -2714,8 +2723,11 @@ next: sg = sg_next(sg); } - if (ops->iotlb_sync_map) - ops->iotlb_sync_map(domain, iova, mapped); + if (ops->iotlb_sync_map) { + ret = ops->iotlb_sync_map(domain, iova, mapped); + if (ret) + goto out_err; + } return mapped; out_err: -- cgit v1.2.3