[PATCH v8 5/5] iommu/vt-d: Implement hw_info for iommu capability query

From: Yi Liu
Date: Wed Aug 16 2023 - 08:15:42 EST


Add intel_iommu_hw_info() to report cap_reg and ecap_reg information.

Acked-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
drivers/iommu/intel/iommu.c | 19 +++++++++++++++++++
include/uapi/linux/iommufd.h | 23 +++++++++++++++++++++++
2 files changed, 42 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5c8c5cdc36cf..9e6f78830ece 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -22,6 +22,7 @@
#include <linux/spinlock.h>
#include <linux/syscore_ops.h>
#include <linux/tboot.h>
+#include <uapi/linux/iommufd.h>

#include "iommu.h"
#include "../dma-iommu.h"
@@ -4732,8 +4733,26 @@ 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, u32 *type)
+{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct intel_iommu *iommu = info->iommu;
+ struct iommu_hw_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);
+ *type = IOMMU_HW_INFO_TYPE_INTEL_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,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 09d5e9cff7b3..42f024c07006 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -372,13 +372,36 @@ struct iommu_hwpt_alloc {
};
#define IOMMU_HWPT_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_ALLOC)

+/**
+ * struct iommu_hw_info_vtd - Intel VT-d hardware information
+ *
+ * @flags: Must be 0
+ * @__reserved: Must be 0
+ *
+ * @cap_reg: Value of Intel VT-d capability register defined in VT-d spec
+ * section 11.4.2 Capability Register.
+ * @ecap_reg: Value of Intel VT-d capability register defined in VT-d spec
+ * section 11.4.3 Extended Capability Register.
+ *
+ * User needs to understand the Intel VT-d specification to decode the
+ * register value.
+ */
+struct iommu_hw_info_vtd {
+ __u32 flags;
+ __u32 __reserved;
+ __aligned_u64 cap_reg;
+ __aligned_u64 ecap_reg;
+};
+
/**
* enum iommu_hw_info_type - IOMMU Hardware Info Types
* @IOMMU_HW_INFO_TYPE_NONE: Used by the drivers that do not report hardware
* info
+ * @IOMMU_HW_INFO_TYPE_INTEL_VTD: Intel VT-d iommu info type
*/
enum iommu_hw_info_type {
IOMMU_HW_INFO_TYPE_NONE,
+ IOMMU_HW_INFO_TYPE_INTEL_VTD,
};

/**
--
2.34.1