iommu/amd: Add amd_iommu_device_info() function

This function can be used to find out which features
necessary for IOMMUv2 usage are available on a given device.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index d5074f4..03944e7 100644 (file)
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3565,3 +3565,46 @@ void amd_iommu_enable_device_erratum(struct pci_dev *pdev, u32 erratum)
        dev_data->errata |= (1 << erratum);
 }
 EXPORT_SYMBOL(amd_iommu_enable_device_erratum);
+
+int amd_iommu_device_info(struct pci_dev *pdev,
+                          struct amd_iommu_device_info *info)
+{
+       int max_pasids;
+       int pos;
+
+       if (pdev == NULL || info == NULL)
+               return -EINVAL;
+
+       if (!amd_iommu_v2_supported())
+               return -EINVAL;
+
+       memset(info, 0, sizeof(*info));
+
+       pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS);
+       if (pos)
+               info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP;
+
+       pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+       if (pos)
+               info->flags |= AMD_IOMMU_DEVICE_FLAG_PRI_SUP;
+
+       pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
+       if (pos) {
+               int features;
+
+               max_pasids = 1 << (9 * (amd_iommu_max_glx_val + 1));
+               max_pasids = min(max_pasids, (1 << 20));
+
+               info->flags |= AMD_IOMMU_DEVICE_FLAG_PASID_SUP;
+               info->max_pasids = min(pci_max_pasids(pdev), max_pasids);
+
+               features = pci_pasid_features(pdev);
+               if (features & PCI_PASID_CAP_EXEC)
+                       info->flags |= AMD_IOMMU_DEVICE_FLAG_EXEC_SUP;
+               if (features & PCI_PASID_CAP_PRIV)
+                       info->flags |= AMD_IOMMU_DEVICE_FLAG_PRIV_SUP;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL(amd_iommu_device_info);

diff --git a/include/linux/amd-iommu.h b/include/linux/amd-iommu.h
index 06688c4..c03c281 100644 (file)
--- a/include/linux/amd-iommu.h
+++ b/include/linux/amd-iommu.h
@@ -119,6 +119,32 @@ typedef int (*amd_iommu_invalid_ppr_cb)(struct pci_dev *pdev,
 extern int amd_iommu_set_invalid_ppr_cb(struct pci_dev *pdev,
                                        amd_iommu_invalid_ppr_cb cb);
 
+/**
+ * amd_iommu_device_info() - Get information about IOMMUv2 support of a
+ *                          PCI device
+ * @pdev: PCI device to query information from
+ * @info: A pointer to an amd_iommu_device_info structure which will contain
+ *       the information about the PCI device
+ *
+ * Returns 0 on success, negative value on error
+ */
+
+#define AMD_IOMMU_DEVICE_FLAG_ATS_SUP     0x1    /* ATS feature supported */
+#define AMD_IOMMU_DEVICE_FLAG_PRI_SUP     0x2    /* PRI feature supported */
+#define AMD_IOMMU_DEVICE_FLAG_PASID_SUP   0x4    /* PASID context supported */
+#define AMD_IOMMU_DEVICE_FLAG_EXEC_SUP    0x8    /* Device may request execution
+                                                   on memory pages */
+#define AMD_IOMMU_DEVICE_FLAG_PRIV_SUP   0x10    /* Device may request
+                                                   super-user privileges */
+
+struct amd_iommu_device_info {
+       int max_pasids;
+       u32 flags;
+};
+
+extern int amd_iommu_device_info(struct pci_dev *pdev,
+                                struct amd_iommu_device_info *info);
+
 #else
 
 static inline int amd_iommu_detect(void) { return -ENODEV; }