iommu/vt-d: Implement hw_info for iommu capability query

Add intel_iommu_hw_info() to report cap_reg and ecap_reg information.

Link: https://lore.kernel.org/r/20230818101033.4100-6-yi.l.liu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5c8c5cdc36cf565a74d49fc94724639414dc279d..9e6f78830ececa186949f0376dcfac3e64730d5b 100644 (file)
--- 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 e01d5ac00dc307a9d3416fe852eca5f438beb22c..b4ba0c0cbab6b8b1562fa359d34f9835a9cde757 100644 (file)
--- 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,
 };
 
 /**