diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/nvme.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/block/nvme.c b/block/nvme.c index 2b5421e..e8dbbc2 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -1030,7 +1030,29 @@ try_map: r = qemu_vfio_dma_map(s->vfio, qiov->iov[i].iov_base, len, true, &iova); + if (r == -ENOSPC) { + /* + * In addition to the -ENOMEM error, the VFIO_IOMMU_MAP_DMA + * ioctl returns -ENOSPC to signal the user exhausted the DMA + * mappings available for a container since Linux kernel commit + * 492855939bdb ("vfio/type1: Limit DMA mappings per container", + * April 2019, see CVE-2019-3882). + * + * This block driver already handles this error path by checking + * for the -ENOMEM error, so we directly replace -ENOSPC by + * -ENOMEM. Beside, -ENOSPC has a specific meaning for blockdev + * coroutines: it triggers BLOCKDEV_ON_ERROR_ENOSPC and + * BLOCK_ERROR_ACTION_STOP which stops the VM, asking the operator + * to add more storage to the blockdev. Not something we can do + * easily with an IOMMU :) + */ + r = -ENOMEM; + } if (r == -ENOMEM && retry) { + /* + * We exhausted the DMA mappings available for our container: + * recycle the volatile IOVA mappings. + */ retry = false; trace_nvme_dma_flush_queue_wait(s); if (s->dma_map_count) { |