This patch adds VFIO_IOMMU_PASID_REQUEST ioctl which aims
to passdown PASID allocation/free request from the virtual
iommu. This is required to get PASID managed in system-wide.

Cc: Kevin Tian <kevin.t...@intel.com>
Signed-off-by: Liu Yi L <yi.l....@intel.com>
Signed-off-by: Yi Sun <yi.y....@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
---
 drivers/vfio/vfio_iommu_type1.c | 114 ++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h       |  25 +++++++++
 2 files changed, 139 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index cd8d3a5..3d73a7d 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2248,6 +2248,83 @@ static int vfio_cache_inv_fn(struct device *dev, void 
*data)
        return iommu_cache_invalidate(dc->domain, dev, &ustruct->info);
 }
 
+static int vfio_iommu_type1_pasid_alloc(struct vfio_iommu *iommu,
+                                        int min_pasid,
+                                        int max_pasid)
+{
+       int ret;
+       ioasid_t pasid;
+       struct mm_struct *mm = NULL;
+
+       mutex_lock(&iommu->lock);
+       if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
+               ret = -EINVAL;
+               goto out_unlock;
+       }
+       mm = get_task_mm(current);
+       /* Track ioasid allocation owner by mm */
+       pasid = ioasid_alloc((struct ioasid_set *)mm, min_pasid,
+                               max_pasid, NULL);
+       if (pasid == INVALID_IOASID) {
+               ret = -ENOSPC;
+               goto out_unlock;
+       }
+       ret = pasid;
+out_unlock:
+       mutex_unlock(&iommu->lock);
+       if (mm)
+               mmput(mm);
+       return ret;
+}
+
+static int vfio_iommu_type1_pasid_free(struct vfio_iommu *iommu,
+                                      unsigned int pasid)
+{
+       struct mm_struct *mm = NULL;
+       void *pdata;
+       int ret = 0;
+
+       mutex_lock(&iommu->lock);
+       if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
+               ret = -EINVAL;
+               goto out_unlock;
+       }
+
+       /**
+        * REVISIT:
+        * There are two cases free could fail:
+        * 1. free pasid by non-owner, we use ioasid_set to track mm, if
+        * the set does not match, caller is not permitted to free.
+        * 2. free before unbind all devices, we can check if ioasid private
+        * data, if data != NULL, then fail to free.
+        */
+       mm = get_task_mm(current);
+       pdata = ioasid_find((struct ioasid_set *)mm, pasid, NULL);
+       if (IS_ERR(pdata)) {
+               if (pdata == ERR_PTR(-ENOENT))
+                       pr_err("PASID %u is not allocated\n", pasid);
+               else if (pdata == ERR_PTR(-EACCES))
+                       pr_err("Free PASID %u by non-owner, denied", pasid);
+               else
+                       pr_err("Error searching PASID %u\n", pasid);
+               ret = -EPERM;
+               goto out_unlock;
+       }
+       if (pdata) {
+               pr_debug("Cannot free pasid %d with private data\n", pasid);
+               /* Expect PASID has no private data if not bond */
+               ret = -EBUSY;
+               goto out_unlock;
+       }
+       ioasid_free(pasid);
+
+out_unlock:
+       if (mm)
+               mmput(mm);
+       mutex_unlock(&iommu->lock);
+       return ret;
+}
+
 static long vfio_iommu_type1_ioctl(void *iommu_data,
                                   unsigned int cmd, unsigned long arg)
 {
@@ -2370,6 +2447,43 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
                                            &ustruct);
                mutex_unlock(&iommu->lock);
                return ret;
+
+       } else if (cmd == VFIO_IOMMU_PASID_REQUEST) {
+               struct vfio_iommu_type1_pasid_request req;
+               int min_pasid, max_pasid, pasid;
+
+               minsz = offsetofend(struct vfio_iommu_type1_pasid_request,
+                                   flag);
+
+               if (copy_from_user(&req, (void __user *)arg, minsz))
+                       return -EFAULT;
+
+               if (req.argsz < minsz)
+                       return -EINVAL;
+
+               switch (req.flag) {
+               /**
+                * TODO: min_pasid and max_pasid align with
+                * typedef unsigned int ioasid_t
+                */
+               case VFIO_IOMMU_PASID_ALLOC:
+                       if (copy_from_user(&min_pasid,
+                               (void __user *)arg + minsz, sizeof(min_pasid)))
+                               return -EFAULT;
+                       if (copy_from_user(&max_pasid,
+                               (void __user *)arg + minsz + sizeof(min_pasid),
+                               sizeof(max_pasid)))
+                               return -EFAULT;
+                       return vfio_iommu_type1_pasid_alloc(iommu,
+                                               min_pasid, max_pasid);
+               case VFIO_IOMMU_PASID_FREE:
+                       if (copy_from_user(&pasid,
+                               (void __user *)arg + minsz, sizeof(pasid)))
+                               return -EFAULT;
+                       return vfio_iommu_type1_pasid_free(iommu, pasid);
+               default:
+                       return -EINVAL;
+               }
        }
 
        return -ENOTTY;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index ccf60a2..04de290 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -807,6 +807,31 @@ struct vfio_iommu_type1_cache_invalidate {
 };
 #define VFIO_IOMMU_CACHE_INVALIDATE      _IO(VFIO_TYPE, VFIO_BASE + 24)
 
+/*
+ * @flag=VFIO_IOMMU_PASID_ALLOC, refer to the @min_pasid and @max_pasid fields
+ * @flag=VFIO_IOMMU_PASID_FREE, refer to @pasid field
+ */
+struct vfio_iommu_type1_pasid_request {
+       __u32   argsz;
+#define VFIO_IOMMU_PASID_ALLOC (1 << 0)
+#define VFIO_IOMMU_PASID_FREE  (1 << 1)
+       __u32   flag;
+       union {
+               struct {
+                       int min_pasid;
+                       int max_pasid;
+               };
+               int pasid;
+       };
+};
+
+/**
+ * VFIO_IOMMU_PASID_REQUEST - _IOWR(VFIO_TYPE, VFIO_BASE + 27,
+ *                             struct vfio_iommu_type1_pasid_request)
+ *
+ */
+#define VFIO_IOMMU_PASID_REQUEST       _IO(VFIO_TYPE, VFIO_BASE + 27)
+
 /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
 
 /*
-- 
2.7.4

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