Hi Joerg,
On 1/11/19 7:16 PM, Joerg Roedel wrote:
+
+static bool
+intel_iommu_dev_has_feat(struct device *dev, enum iommu_dev_features feat)
+{
+ struct device_domain_info *info = dev->archdata.iommu;
+
+ if (feat == IOMMU_DEV_FEAT_AUX)
+ return scalable_mode_support() && info && info->auxd_enabled;
+
+ return false;
+}
Why is this checking the auxd_enabled flag? The function should just
return whether the device_supports_ scalable mode, not whether it is
enabled.
Yes, as the API name implies, it should return the device capability
instead of enable/disable status. I misused this API in the IOMMU
driver.
Since we already have iommu_dev_enable/disable_feature() to enable and
disable an iommu specific feature, is it possible to add another API to
query whether a specific feature has been enabled?
How about
bool iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX)?
This is necessary for the third party drivers (like vfio) to determine
which domain attach interface it should use:
if (iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX))
iommmu_aux_attach_device(domain, dev)
else
iommu_attach_device(domain, dev)
Best regards,
Lu Baolu
