From 34b48c704d194738eef0893aa06e412bdc8a972f Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Thu, 1 Apr 2021 17:47:12 +0200 Subject: iommu: Separate IOMMU_DEV_FEAT_IOPF from IOMMU_DEV_FEAT_SVA Some devices manage I/O Page Faults (IOPF) themselves instead of relying on PCIe PRI or Arm SMMU stall. Allow their drivers to enable SVA without mandating IOMMU-managed IOPF. The other device drivers now need to first enable IOMMU_DEV_FEAT_IOPF before enabling IOMMU_DEV_FEAT_SVA. Enabling IOMMU_DEV_FEAT_IOPF on its own doesn't have any effect visible to the device driver, it is used in combination with other features. Reviewed-by: Eric Auger Reviewed-by: Lu Baolu Signed-off-by: Jean-Philippe Brucker Link: https://lore.kernel.org/r/20210401154718.307519-4-jean-philippe@linaro.org Signed-off-by: Joerg Roedel --- include/linux/iommu.h | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) (limited to 'include/linux/iommu.h') diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 16ce75693d83..45c4eb372f56 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -156,10 +156,24 @@ struct iommu_resv_region { enum iommu_resv_type type; }; -/* Per device IOMMU features */ +/** + * enum iommu_dev_features - Per device IOMMU features + * @IOMMU_DEV_FEAT_AUX: Auxiliary domain feature + * @IOMMU_DEV_FEAT_SVA: Shared Virtual Addresses + * @IOMMU_DEV_FEAT_IOPF: I/O Page Faults such as PRI or Stall. Generally + * enabling %IOMMU_DEV_FEAT_SVA requires + * %IOMMU_DEV_FEAT_IOPF, but some devices manage I/O Page + * Faults themselves instead of relying on the IOMMU. When + * supported, this feature must be enabled before and + * disabled after %IOMMU_DEV_FEAT_SVA. + * + * Device drivers query whether a feature is supported using + * iommu_dev_has_feature(), and enable it using iommu_dev_enable_feature(). + */ enum iommu_dev_features { - IOMMU_DEV_FEAT_AUX, /* Aux-domain feature */ - IOMMU_DEV_FEAT_SVA, /* Shared Virtual Addresses */ + IOMMU_DEV_FEAT_AUX, + IOMMU_DEV_FEAT_SVA, + IOMMU_DEV_FEAT_IOPF, }; #define IOMMU_PASID_INVALID (-1U) -- cgit v1.2.3