[PATCH v3 6/7] vfio: Remove reports of DMA mapping errors in backends

["Cédric Le Goater" <clg@redhat.com>]

Currently, the mapping handlers of the IOMMU backends, VFIO IOMMU Type
1 aka. legacy and IOMMUFD, return an errno and also report an error.
This can lead to excessive log messages at runtime for recurring DMA
mapping errors. Since these errors are already reported by the callers
in the vfio_container_dma_un/map() routines, simply remove them and
allow the callers to handle the reporting.

The mapping handler of the IOMMUFD backend has a comment suggesting
MMIO region mapping failures return EFAULT. I am not sure this is
entirely true, so keep the EFAULT case until the conditions are
clarified.

Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 backends/iommufd.c  | 3 ---
 hw/vfio/container.c | 2 --
 2 files changed, 5 deletions(-)

diff --git a/backends/iommufd.c b/backends/iommufd.c
index 7b4fc8ec460ef635b9ed5ac7b201f124476b512a..d57da44755be3d7fdba74f7dbecfe6d1c89921ba 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -167,8 +167,6 @@ int iommufd_backend_map_dma(IOMMUFDBackend *be, uint32_t ioas_id, hwaddr iova,
         /* TODO: Not support mapping hardware PCI BAR region for now. */
         if (errno == EFAULT) {
             warn_report("IOMMU_IOAS_MAP failed: %m, PCI BAR?");
-        } else {
-            error_report("IOMMU_IOAS_MAP failed: %m");
         }
     }
     return ret;
@@ -203,7 +201,6 @@ int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
 
     if (ret) {
         ret = -errno;
-        error_report("IOMMU_IOAS_UNMAP failed: %m");
     }
     return ret;
 }
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 4ebb5268088d0a2006e0ed04afec0ee746ed2c1d..7c57bdd27b72731db5cf4f9446d954e143b4747e 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -159,7 +159,6 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
             unmap.size -= 1ULL << ctz64(bcontainer->pgsizes);
             continue;
         }
-        error_report("VFIO_UNMAP_DMA failed: %s", strerror(errno));
         return -errno;
     }
 
@@ -204,7 +203,6 @@ static int vfio_legacy_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
         return 0;
     }
 
-    error_report("VFIO_MAP_DMA failed: %s", strerror(errno));
     return -errno;
 }
 
-- 
2.48.1