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| author | Niklas Schnelle <schnelle@linux.ibm.com> | 2023-09-28 16:31:35 +0200 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2023-10-02 08:42:57 +0200 |
| commit | fa4c4507099f781ca89a748c480af9cf97629726 (patch) | |
| tree | cbc571a65429151d3e53f8ae92e252d89d28f785 /drivers/iommu/iommu.c | |
| parent | ccb76c5751634541bfd2222374f46e1dea83d525 (diff) | |
| download | lwn-fa4c4507099f781ca89a748c480af9cf97629726.tar.gz lwn-fa4c4507099f781ca89a748c480af9cf97629726.zip | |
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 <baolu.lu@linux.intel.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> # sun50i
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20230928-dma_iommu-v13-1-9e5fc4dacc36@linux.ibm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/iommu.c')
| -rw-r--r-- | drivers/iommu/iommu.c | 20 |
1 files changed, 16 insertions, 4 deletions
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: |