[PATCH 2/6] iommu/vt-d: Implement hw_info for iommu capability query

[Yi Liu]

From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

To support nested translation in the userspace, it should check the
underlying hardware information for the capabilities.

Add intel_iommu_hw_info() to report cap_reg and ecap_reg information.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel/iommu.c  | 19 +++++++++++++++++++
 drivers/iommu/intel/iommu.h  |  1 +
 include/uapi/linux/iommufd.h | 21 +++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 59df7e42fd53..929f600cc350 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4760,8 +4760,26 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
 	intel_pasid_tear_down_entry(iommu, dev, pasid, false);
 }
 
+static void *intel_iommu_hw_info(struct device *dev, u32 *length)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu = info->iommu;
+	struct iommu_device_info_vtd *vtd;
+
+	vtd = kzalloc(sizeof(*vtd), GFP_KERNEL);
+	if (!vtd)
+		return ERR_PTR(-ENOMEM);
+
+	vtd->cap_reg = iommu->cap;
+	vtd->ecap_reg = iommu->ecap;
+	*length = sizeof(*vtd);
+
+	return vtd;
+}
+
 const struct iommu_ops intel_iommu_ops = {
 	.capable		= intel_iommu_capable,
+	.hw_info		= intel_iommu_hw_info,
 	.domain_alloc		= intel_iommu_domain_alloc,
 	.probe_device		= intel_iommu_probe_device,
 	.probe_finalize		= intel_iommu_probe_finalize,
@@ -4774,6 +4792,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.def_domain_type	= device_def_domain_type,
 	.remove_dev_pasid	= intel_iommu_remove_dev_pasid,
 	.pgsize_bitmap		= SZ_4K,
+	.driver_type		= IOMMU_DEVICE_DATA_INTEL_VTD,
 #ifdef CONFIG_INTEL_IOMMU_SVM
 	.page_response		= intel_svm_page_response,
 #endif
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 06e61e474856..2e70265d4ceb 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -22,6 +22,7 @@
 #include <linux/ioasid.h>
 #include <linux/bitfield.h>
 #include <linux/xarray.h>
+#include <uapi/linux/iommufd.h>
 
 #include <asm/cacheflush.h>
 #include <asm/iommu.h>
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 2309edb55028..fda75c8450ee 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -347,7 +347,28 @@ struct iommu_vfio_ioas {
 
 /**
  * enum iommu_device_data_type - IOMMU hardware Data types
+ * @IOMMU_DEVICE_DATA_INTEL_VTD: Intel VT-d iommu data type
  */
 enum iommu_device_data_type {
+	IOMMU_DEVICE_DATA_INTEL_VTD = 1,
+};
+
+/**
+ * struct iommu_device_info_vtd - Intel VT-d device info
+ *
+ * @flags: Must be set to 0
+ * @__reserved: Must be 0
+ * @cap_reg: Value of Intel VT-d capability register defined in chapter
+ *	     11.4.2 of Intel VT-d spec.
+ * @ecap_reg: Value of Intel VT-d capability register defined in chapter
+ *	     11.4.3 of Intel VT-d spec.
+ *
+ * Intel hardware iommu capability.
+ */
+struct iommu_device_info_vtd {
+	__u32 flags;
+	__u32 __reserved;
+	__aligned_u64 cap_reg;
+	__aligned_u64 ecap_reg;
 };
 #endif
-- 
2.34.1