[PATCH 2/2] iommufd: Report ATS not supported status via IOMMU_GET_HW_INFO

[Shameer Kolothum <skolothumtho@nvidia.com>]

If the IOMMU driver reports that ATS is not supported for a device, set
the IOMMU_HW_CAP_PCI_ATS_NOT_SUPPORTED flag in the returned hardware
capabilities.

When this flag is set, ATS is not supported and not used for the device.

Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
---
 include/uapi/linux/iommufd.h   | 3 +++
 drivers/iommu/iommufd/device.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 1dafbc552d37..d85a2d3e1b40 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -695,11 +695,14 @@ enum iommu_hw_info_type {
  * @IOMMU_HW_CAP_PCI_PASID_PRIV: Privileged Mode Supported, user ignores it
  *                               when the struct
  *                               iommu_hw_info::out_max_pasid_log2 is zero.
+ * @IOMMU_HW_CAP_PCI_ATS_NOT_SUPPORTED: ATS is not supported and not used on
+ *                                      this device.
  */
 enum iommufd_hw_capabilities {
 	IOMMU_HW_CAP_DIRTY_TRACKING = 1 << 0,
 	IOMMU_HW_CAP_PCI_PASID_EXEC = 1 << 1,
 	IOMMU_HW_CAP_PCI_PASID_PRIV = 1 << 2,
+	IOMMU_HW_CAP_PCI_ATS_NOT_SUPPORTED = 1 << 3,
 };
 
 /**
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 344d620cdecc..2e98818806c0 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -1624,6 +1624,9 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd)
 	if (device_iommu_capable(idev->dev, IOMMU_CAP_DIRTY_TRACKING))
 		cmd->out_capabilities |= IOMMU_HW_CAP_DIRTY_TRACKING;
 
+	if (device_iommu_capable(idev->dev, IOMMU_CAP_PCI_ATS_NOT_SUPPORTED))
+		cmd->out_capabilities |= IOMMU_HW_CAP_PCI_ATS_NOT_SUPPORTED;
+
 	cmd->out_max_pasid_log2 = 0;
 	/*
 	 * Currently, all iommu drivers enable PASID in the probe_device()
-- 
2.43.0