diff mbox series

[04/12] iommufd: Pass parent hwpt and user_data to iommufd_hw_pagetable_alloc()

Message ID 20230309080910.607396-5-yi.l.liu@intel.com
State New
Headers
Series iommufd: Add nesting infrastructure |

Commit Message

Yi Liu March 9, 2023, 8:09 a.m. UTC 
  Nested translation has stage-1 and stage-2 page tables. A stage-1 page
table is managed by user space, and it needs to work with a stage-2 page
table, which is a parent hwpt for the stage-1 hwpt.

iommu core already supports accepting parent iommu_domain and user_data
to allocate an iommu_domain. This makes iommufd_hw_pagetable_alloc() to
accept the parent hwpt and user_data, and relays them to iommu core, to
prepare for supporting hw_pagetable allocation with user_data.

Also, add a parent pointer in struct iommufd_hw_pagetable for taking and
releasing its refcount.

Co-developed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/iommu/iommufd/device.c          |  2 +-
 drivers/iommu/iommufd/hw_pagetable.c    | 28 ++++++++++++++++++++++---
 drivers/iommu/iommufd/iommufd_private.h |  5 ++++-
 3 files changed, 30 insertions(+), 5 deletions(-)

Comments

Baolu Lu March 10, 2023, 2:10 a.m. UTC | #1 
On 3/9/23 4:09 PM, Yi Liu wrote:
> Nested translation has stage-1 and stage-2 page tables. A stage-1 page
> table is managed by user space, and it needs to work with a stage-2 page
> table, which is a parent hwpt for the stage-1 hwpt.
> 
> iommu core already supports accepting parent iommu_domain and user_data
> to allocate an iommu_domain. This makes iommufd_hw_pagetable_alloc() to
> accept the parent hwpt and user_data, and relays them to iommu core, to
> prepare for supporting hw_pagetable allocation with user_data.
> 
> Also, add a parent pointer in struct iommufd_hw_pagetable for taking and
> releasing its refcount.
> 
> Co-developed-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>   drivers/iommu/iommufd/device.c          |  2 +-
>   drivers/iommu/iommufd/hw_pagetable.c    | 28 ++++++++++++++++++++++---
>   drivers/iommu/iommufd/iommufd_private.h |  5 ++++-
>   3 files changed, 30 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index 5c352807d946..19cd6df46c6a 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -558,7 +558,7 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
>   	}
>   
>   	hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev,
> -					  immediate_attach);
> +					  NULL, NULL, immediate_attach);
>   	if (IS_ERR(hwpt)) {
>   		destroy_hwpt = ERR_CAST(hwpt);
>   		goto out_unlock;
> diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
> index 84b4a11e62f8..16e92a1c150b 100644
> --- a/drivers/iommu/iommufd/hw_pagetable.c
> +++ b/drivers/iommu/iommufd/hw_pagetable.c
> @@ -24,6 +24,8 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
>   	if (hwpt->domain)
>   		iommu_domain_free(hwpt->domain);
>   
> +	if (hwpt->parent)
> +		refcount_dec(&hwpt->parent->obj.users);
>   	refcount_dec(&hwpt->ioas->obj.users);
>   }
>   
> @@ -46,6 +48,8 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
>    * @ictx: iommufd context
>    * @ioas: IOAS to associate the domain with
>    * @idev: Device to get an iommu_domain for
> + * @parent: Optional parent HWPT to associate with the domain with
> + * @user_data: Optional user_data pointer
>    * @immediate_attach: True if idev should be attached to the hwpt
>    *
>    * Allocate a new iommu_domain and return it as a hw_pagetable. The HWPT
> @@ -54,14 +58,20 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
>    */
>   struct iommufd_hw_pagetable *
>   iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
> -			   struct iommufd_device *idev, bool immediate_attach)
> +			   struct iommufd_device *idev,
> +			   struct iommufd_hw_pagetable *parent,
> +			   void *user_data, bool immediate_attach)
>   {
>   	const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
> +	struct iommu_domain *parent_domain = NULL;
>   	struct iommufd_hw_pagetable *hwpt;
>   	int rc;
>   
>   	lockdep_assert_held(&ioas->mutex);
>   
> +	if (parent && !ops->domain_alloc_user)
> +		return ERR_PTR(-EOPNOTSUPP);

My understanding here is that we are checking whether domain_alloc_user
is required. It seems that as long as the caller inputs a valid
user_data or parent, domain_alloc_user is required. If so,

	if ((user_data || parent) && !ops->domain_alloc_user)
		return ERR_PTR(-EOPNOTSUPP);

Best regards,
baolu
Jason Gunthorpe March 10, 2023, 5:49 p.m. UTC | #2 
On Fri, Mar 10, 2023 at 10:10:56AM +0800, Baolu Lu wrote:
> > @@ -54,14 +58,20 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
> >    */
> >   struct iommufd_hw_pagetable *
> >   iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
> > -			   struct iommufd_device *idev, bool immediate_attach)
> > +			   struct iommufd_device *idev,
> > +			   struct iommufd_hw_pagetable *parent,
> > +			   void *user_data, bool immediate_attach)
> >   {
> >   	const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
> > +	struct iommu_domain *parent_domain = NULL;
> >   	struct iommufd_hw_pagetable *hwpt;
> >   	int rc;
> >   	lockdep_assert_held(&ioas->mutex);
> > +	if (parent && !ops->domain_alloc_user)
> > +		return ERR_PTR(-EOPNOTSUPP);
> 
> My understanding here is that we are checking whether domain_alloc_user
> is required. It seems that as long as the caller inputs a valid
> user_data or parent, domain_alloc_user is required. If so,
> 
> 	if ((user_data || parent) && !ops->domain_alloc_user)
> 		return ERR_PTR(-EOPNOTSUPP);

Yes

Jason
Tian, Kevin March 17, 2023, 10:23 a.m. UTC | #3 
> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Thursday, March 9, 2023 4:09 PM
> 
> +	/* It must be either NESTED or UNMANAGED, depending on
> parent_domain */
> +	if ((parent_domain && hwpt->domain->type !=
> IOMMU_DOMAIN_NESTED) ||
> +	    (!parent_domain && hwpt->domain->type !=
> IOMMU_DOMAIN_UNMANAGED))
> +		goto out_abort;
> +

WARN_ON()
Jason Gunthorpe March 20, 2023, 12:47 p.m. UTC | #4 
On Fri, Mar 17, 2023 at 10:23:54AM +0000, Tian, Kevin wrote:
> > From: Liu, Yi L <yi.l.liu@intel.com>
> > Sent: Thursday, March 9, 2023 4:09 PM
> > 
> > +	/* It must be either NESTED or UNMANAGED, depending on
> > parent_domain */
> > +	if ((parent_domain && hwpt->domain->type !=
> > IOMMU_DOMAIN_NESTED) ||
> > +	    (!parent_domain && hwpt->domain->type !=
> > IOMMU_DOMAIN_UNMANAGED))
> > +		goto out_abort;
> > +
> 
> WARN_ON()

Wouldn't that be userspace triggerable? It gets to pick the hwpt used.

Jason
Tian, Kevin March 21, 2023, 1:25 a.m. UTC | #5 
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Monday, March 20, 2023 8:47 PM
> 
> On Fri, Mar 17, 2023 at 10:23:54AM +0000, Tian, Kevin wrote:
> > > From: Liu, Yi L <yi.l.liu@intel.com>
> > > Sent: Thursday, March 9, 2023 4:09 PM
> > >
> > > +	/* It must be either NESTED or UNMANAGED, depending on
> > > parent_domain */
> > > +	if ((parent_domain && hwpt->domain->type !=
> > > IOMMU_DOMAIN_NESTED) ||
> > > +	    (!parent_domain && hwpt->domain->type !=
> > > IOMMU_DOMAIN_UNMANAGED))
> > > +		goto out_abort;
> > > +
> >
> > WARN_ON()
> 
> Wouldn't that be userspace triggerable? It gets to pick the hwpt used.
> 

The domain type is set by iommu driver instead of userspace. A sane
driver should pass above check, if it claims to support nested.
diff mbox series

Patch

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 5c352807d946..19cd6df46c6a 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -558,7 +558,7 @@  iommufd_device_auto_get_domain(struct iommufd_device *idev,
 	}
 
 	hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev,
-					  immediate_attach);
+					  NULL, NULL, immediate_attach);
 	if (IS_ERR(hwpt)) {
 		destroy_hwpt = ERR_CAST(hwpt);
 		goto out_unlock;
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 84b4a11e62f8..16e92a1c150b 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -24,6 +24,8 @@  void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
 	if (hwpt->domain)
 		iommu_domain_free(hwpt->domain);
 
+	if (hwpt->parent)
+		refcount_dec(&hwpt->parent->obj.users);
 	refcount_dec(&hwpt->ioas->obj.users);
 }
 
@@ -46,6 +48,8 @@  int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
  * @ictx: iommufd context
  * @ioas: IOAS to associate the domain with
  * @idev: Device to get an iommu_domain for
+ * @parent: Optional parent HWPT to associate with the domain with
+ * @user_data: Optional user_data pointer
  * @immediate_attach: True if idev should be attached to the hwpt
  *
  * Allocate a new iommu_domain and return it as a hw_pagetable. The HWPT
@@ -54,14 +58,20 @@  int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
  */
 struct iommufd_hw_pagetable *
 iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
-			   struct iommufd_device *idev, bool immediate_attach)
+			   struct iommufd_device *idev,
+			   struct iommufd_hw_pagetable *parent,
+			   void *user_data, bool immediate_attach)
 {
 	const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
+	struct iommu_domain *parent_domain = NULL;
 	struct iommufd_hw_pagetable *hwpt;
 	int rc;
 
 	lockdep_assert_held(&ioas->mutex);
 
+	if (parent && !ops->domain_alloc_user)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	hwpt = iommufd_object_alloc(ictx, hwpt, IOMMUFD_OBJ_HW_PAGETABLE);
 	if (IS_ERR(hwpt))
 		return hwpt;
@@ -70,9 +80,15 @@  iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 	/* Pairs with iommufd_hw_pagetable_destroy() */
 	refcount_inc(&ioas->obj.users);
 	hwpt->ioas = ioas;
+	if (parent) {
+		hwpt->parent = parent;
+		parent_domain = parent->domain;
+		refcount_inc(&parent->obj.users);
+	}
 
 	if (ops->domain_alloc_user)
-		hwpt->domain = ops->domain_alloc_user(idev->dev, NULL, NULL);
+		hwpt->domain = ops->domain_alloc_user(idev->dev,
+						      parent_domain, user_data);
 	else
 		hwpt->domain = iommu_domain_alloc(idev->dev->bus);
 	if (!hwpt->domain) {
@@ -80,6 +96,11 @@  iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
 		goto out_abort;
 	}
 
+	/* It must be either NESTED or UNMANAGED, depending on parent_domain */
+	if ((parent_domain && hwpt->domain->type != IOMMU_DOMAIN_NESTED) ||
+	    (!parent_domain && hwpt->domain->type != IOMMU_DOMAIN_UNMANAGED))
+		goto out_abort;
+
 	/*
 	 * Set the coherency mode before we do iopt_table_add_domain() as some
 	 * iommus have a per-PTE bit that controls it and need to decide before
@@ -150,7 +171,8 @@  int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 	}
 
 	mutex_lock(&ioas->mutex);
-	hwpt = iommufd_hw_pagetable_alloc(ucmd->ictx, ioas, idev, false);
+	hwpt = iommufd_hw_pagetable_alloc(ucmd->ictx, ioas, idev,
+					  NULL, NULL, false);
 	mutex_unlock(&ioas->mutex);
 	if (IS_ERR(hwpt)) {
 		rc = PTR_ERR(hwpt);
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 05b5ad66f716..182c074eecdc 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -243,6 +243,7 @@  int iommufd_vfio_ioas(struct iommufd_ucmd *ucmd);
  */
 struct iommufd_hw_pagetable {
 	struct iommufd_object obj;
+	struct iommufd_hw_pagetable *parent;
 	struct iommufd_ioas *ioas;
 	struct iommu_domain *domain;
 	bool auto_domain : 1;
@@ -254,7 +255,9 @@  struct iommufd_hw_pagetable {
 
 struct iommufd_hw_pagetable *
 iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
-			   struct iommufd_device *idev, bool immediate_attach);
+			   struct iommufd_device *idev,
+			   struct iommufd_hw_pagetable *parent,
+			   void *user_data, bool immediate_attach);
 int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt);
 int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
 				struct iommufd_device *idev);