[RFC v2 2/3] vfio/type1: VFIO_IOMMU_PASID_REQUEST(alloc/free)

Liu Yi L
2019-10-24T12:52:58Z

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.tian@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@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