diff options
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/idxd/cdev.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c index c2808fd081d6..a9b96b18772f 100644 --- a/drivers/dma/idxd/cdev.c +++ b/drivers/dma/idxd/cdev.c @@ -312,6 +312,24 @@ static int idxd_user_drv_probe(struct idxd_dev *idxd_dev) if (idxd->state != IDXD_DEV_ENABLED) return -ENXIO; + /* + * User type WQ is enabled only when SVA is enabled for two reasons: + * - If no IOMMU or IOMMU Passthrough without SVA, userspace + * can directly access physical address through the WQ. + * - The IDXD cdev driver does not provide any ways to pin + * user pages and translate the address from user VA to IOVA or + * PA without IOMMU SVA. Therefore the application has no way + * to instruct the device to perform DMA function. This makes + * the cdev not usable for normal application usage. + */ + if (!device_user_pasid_enabled(idxd)) { + idxd->cmd_status = IDXD_SCMD_WQ_USER_NO_IOMMU; + dev_dbg(&idxd->pdev->dev, + "User type WQ cannot be enabled without SVA.\n"); + + return -EOPNOTSUPP; + } + mutex_lock(&wq->wq_lock); wq->type = IDXD_WQT_USER; rc = drv_enable_wq(wq); |