diff mbox series

[v5,2/4] iommufd: Add iommufd_access_replace() API

Message ID 2c3fa7a21373ee10af7cc9f8c370945a08341930.1679559476.git.nicolinc@nvidia.com (mailing list archive)
State New, archived
Headers show
Series cover-letter: Add IO page table replacement support | expand

Commit Message

Nicolin Chen March 23, 2023, 8:33 a.m. UTC 
Extract all common procedure, between the iommufd_access_attach() API and
the new iommufd_access_replace() API, to an iommufd_access_change_pt()
helper.

Add iommufd_access_replace() function for VFIO emulated pathway to use.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/device.c          | 60 ++++++++++++++++++++-----
 include/linux/iommufd.h                 |  1 +
 tools/testing/selftests/iommu/iommfd*.c |  0
 3 files changed, 50 insertions(+), 11 deletions(-)
 create mode 100644 tools/testing/selftests/iommu/iommfd*.c

Comments

Tian, Kevin March 24, 2023, 3:02 a.m. UTC | #1 
> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Thursday, March 23, 2023 4:33 PM
> 
> +int iommufd_access_replace(struct iommufd_access *access, u32 ioas_id)
> +{
> +	struct iommufd_ioas *new_ioas;
> +
> +	mutex_lock(&access->ioas_lock);
> +	if (!access->ioas) {
>  		mutex_unlock(&access->ioas_lock);
> -		iommufd_put_object(obj);
> -		return rc;
> +		return -ENOENT;
> +	}
> +	if (access->ioas->obj.id == ioas_id) {
> +		mutex_unlock(&access->ioas_lock);
> +		return 0;
>  	}
> -	iommufd_ref_to_users(obj);
> 
> +	new_ioas = iommufd_access_change_pt(access, ioas_id);
> +	if (IS_ERR(new_ioas)) {
> +		mutex_unlock(&access->ioas_lock);
> +		return PTR_ERR(new_ioas);
> +	}
> +	__iommufd_access_detach(access);
>  	access->ioas = new_ioas;
>  	access->ioas_unpin = new_ioas;

Above three lines can be moved into iommufd_access_change_pt():

	If (access->ioas)
		__iommufd_access_detach(access);
	access->ioas = new_ioas;
	access->ioas_unpin = new_ioas;

Then both attach/replace can end by calling the common function.
Nicolin Chen March 24, 2023, 5:02 p.m. UTC | #2 
On Fri, Mar 24, 2023 at 03:02:46AM +0000, Tian, Kevin wrote:
> External email: Use caution opening links or attachments
> 
> 
> > From: Nicolin Chen <nicolinc@nvidia.com>
> > Sent: Thursday, March 23, 2023 4:33 PM
> >
> > +int iommufd_access_replace(struct iommufd_access *access, u32 ioas_id)
> > +{
> > +     struct iommufd_ioas *new_ioas;
> > +
> > +     mutex_lock(&access->ioas_lock);
> > +     if (!access->ioas) {
> >               mutex_unlock(&access->ioas_lock);
> > -             iommufd_put_object(obj);
> > -             return rc;
> > +             return -ENOENT;
> > +     }
> > +     if (access->ioas->obj.id == ioas_id) {
> > +             mutex_unlock(&access->ioas_lock);
> > +             return 0;
> >       }
> > -     iommufd_ref_to_users(obj);
> >
> > +     new_ioas = iommufd_access_change_pt(access, ioas_id);
> > +     if (IS_ERR(new_ioas)) {
> > +             mutex_unlock(&access->ioas_lock);
> > +             return PTR_ERR(new_ioas);
> > +     }
> > +     __iommufd_access_detach(access);
> >       access->ioas = new_ioas;
> >       access->ioas_unpin = new_ioas;
> 
> Above three lines can be moved into iommufd_access_change_pt():
> 
>         If (access->ioas)
>                 __iommufd_access_detach(access);
>         access->ioas = new_ioas;
>         access->ioas_unpin = new_ioas;
> 
> Then both attach/replace can end by calling the common function.

OK. Will do that in v6.

Thanks
Nicolin
diff mbox series

Patch

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 012e85fc6d77..3b39b76fbc3b 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -746,39 +746,77 @@  void iommufd_access_detach(struct iommufd_access *access)
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_access_detach, IOMMUFD);
 
-int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id)
+static struct iommufd_ioas *
+iommufd_access_change_pt(struct iommufd_access *access, u32 ioas_id)
 {
 	struct iommufd_ioas *new_ioas;
 	struct iommufd_object *obj;
 	int rc = 0;
 
+	lockdep_assert_held(&access->ioas_lock);
+
+	obj = iommufd_get_object(access->ictx, ioas_id, IOMMUFD_OBJ_IOAS);
+	if (IS_ERR(obj))
+		return (struct iommufd_ioas *)obj;
+	new_ioas = container_of(obj, struct iommufd_ioas, obj);
+
+	rc = iopt_add_access(&new_ioas->iopt, access);
+	if (rc) {
+		iommufd_put_object(obj);
+		return ERR_PTR(rc);
+	}
+	iommufd_ref_to_users(obj);
+	return new_ioas;
+}
+
+int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id)
+{
+	struct iommufd_ioas *new_ioas;
+
 	mutex_lock(&access->ioas_lock);
 	if (access->ioas != NULL && access->ioas->obj.id != ioas_id) {
 		mutex_unlock(&access->ioas_lock);
 		return -EINVAL;
 	}
 
-	obj = iommufd_get_object(access->ictx, ioas_id, IOMMUFD_OBJ_IOAS);
-	if (IS_ERR(obj)) {
+	new_ioas = iommufd_access_change_pt(access, ioas_id);
+	if (IS_ERR(new_ioas)) {
 		mutex_unlock(&access->ioas_lock);
-		return PTR_ERR(obj);
+		return PTR_ERR(new_ioas);
 	}
-	new_ioas = container_of(obj, struct iommufd_ioas, obj);
+	access->ioas = new_ioas;
+	access->ioas_unpin = new_ioas;
+	mutex_unlock(&access->ioas_lock);
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_access_attach, IOMMUFD);
 
-	rc = iopt_add_access(&new_ioas->iopt, access);
-	if (rc) {
+int iommufd_access_replace(struct iommufd_access *access, u32 ioas_id)
+{
+	struct iommufd_ioas *new_ioas;
+
+	mutex_lock(&access->ioas_lock);
+	if (!access->ioas) {
 		mutex_unlock(&access->ioas_lock);
-		iommufd_put_object(obj);
-		return rc;
+		return -ENOENT;
+	}
+	if (access->ioas->obj.id == ioas_id) {
+		mutex_unlock(&access->ioas_lock);
+		return 0;
 	}
-	iommufd_ref_to_users(obj);
 
+	new_ioas = iommufd_access_change_pt(access, ioas_id);
+	if (IS_ERR(new_ioas)) {
+		mutex_unlock(&access->ioas_lock);
+		return PTR_ERR(new_ioas);
+	}
+	__iommufd_access_detach(access);
 	access->ioas = new_ioas;
 	access->ioas_unpin = new_ioas;
 	mutex_unlock(&access->ioas_lock);
 	return 0;
 }
-EXPORT_SYMBOL_NS_GPL(iommufd_access_attach, IOMMUFD);
+EXPORT_SYMBOL_NS_GPL(iommufd_access_replace, IOMMUFD);
 
 /**
  * iommufd_access_notify_unmap - Notify users of an iopt to stop using it
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 7c79f9b33246..cd7ae5a625fc 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -46,6 +46,7 @@  iommufd_access_create(struct iommufd_ctx *ictx,
 		      const struct iommufd_access_ops *ops, void *data, u32 *id);
 void iommufd_access_destroy(struct iommufd_access *access);
 int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id);
+int iommufd_access_replace(struct iommufd_access *access, u32 ioas_id);
 void iommufd_access_detach(struct iommufd_access *access);
 
 void iommufd_ctx_get(struct iommufd_ctx *ictx);
diff --git a/tools/testing/selftests/iommu/iommfd*.c b/tools/testing/selftests/iommu/iommfd*.c
new file mode 100644
index 000000000000..e69de29bb2d1