diff mbox series

[v4,03/19] vfio: Accept vfio device file in the driver facing kAPI

Message ID 20230221034812.138051-4-yi.l.liu@intel.com (mailing list archive)
State New, archived
Headers show
Series Add vfio_device cdev for iommufd support | expand

Commit Message

Yi Liu Feb. 21, 2023, 3:47 a.m. UTC 
This makes the vfio file kAPIs to accepte vfio device files, also a
preparation for vfio device cdev support.

For the kvm set with vfio device file, kvm pointer is stored in struct
vfio_device_file, and use kvm_ref_lock to protect kvm set and kvm
pointer usage within VFIO. This kvm pointer will be set to vfio_device
after device file is bound to iommufd in the cdev path.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/vfio/vfio.h      |  2 ++
 drivers/vfio/vfio_main.c | 51 ++++++++++++++++++++++++++++++++++++----
 2 files changed, 49 insertions(+), 4 deletions(-)

Comments

Tian, Kevin Feb. 22, 2023, 7:15 a.m. UTC | #1 
> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Tuesday, February 21, 2023 11:48 AM
> 
>  /**
>   * vfio_file_is_valid - True if the file is valid vfio file
>   * @file: VFIO group file or VFIO device file
>   */
>  bool vfio_file_is_valid(struct file *file)
>  {
> -	return vfio_group_from_file(file);
> +	return vfio_group_from_file(file) ||
> +	       vfio_device_from_file(file);
>  }
>  EXPORT_SYMBOL_GPL(vfio_file_is_valid);

Following previous Alex's comment I'd leave pci hot reset path
to continue calling vfio_file_is_group() at this point so the uAPI
semantics is not changed here before patch 9 comes to properly
handle device fd in that path.
Yi Liu Feb. 26, 2023, 12:20 p.m. UTC | #2 
> From: Tian, Kevin <kevin.tian@intel.com>
> Sent: Wednesday, February 22, 2023 3:16 PM
> 
> > From: Liu, Yi L <yi.l.liu@intel.com>
> > Sent: Tuesday, February 21, 2023 11:48 AM
> >
> >  /**
> >   * vfio_file_is_valid - True if the file is valid vfio file
> >   * @file: VFIO group file or VFIO device file
> >   */
> >  bool vfio_file_is_valid(struct file *file)
> >  {
> > -	return vfio_group_from_file(file);
> > +	return vfio_group_from_file(file) ||
> > +	       vfio_device_from_file(file);
> >  }
> >  EXPORT_SYMBOL_GPL(vfio_file_is_valid);
> 
> Following previous Alex's comment I'd leave pci hot reset path
> to continue calling vfio_file_is_group() at this point so the uAPI
> semantics is not changed here before patch 9 comes to properly
> handle device fd in that path.

Done.
diff mbox series

Patch

diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index f237e9410d1e..cee979a1b90f 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -18,6 +18,8 @@  struct vfio_container;
 
 struct vfio_device_file {
 	struct vfio_device *device;
+	spinlock_t kvm_ref_lock; /* protect kvm field */
+	struct kvm *kvm;
 };
 
 void vfio_device_put_registration(struct vfio_device *device);
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 64dbe5266c4b..28db0a563805 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -406,6 +406,7 @@  vfio_allocate_device_file(struct vfio_device *device)
 		return ERR_PTR(-ENOMEM);
 
 	df->device = device;
+	spin_lock_init(&df->kvm_ref_lock);
 
 	return df;
 }
@@ -1167,13 +1168,23 @@  const struct file_operations vfio_device_fops = {
 	.mmap		= vfio_device_fops_mmap,
 };
 
+static struct vfio_device *vfio_device_from_file(struct file *file)
+{
+	struct vfio_device_file *df = file->private_data;
+
+	if (file->f_op != &vfio_device_fops)
+		return NULL;
+	return df->device;
+}
+
 /**
  * vfio_file_is_valid - True if the file is valid vfio file
  * @file: VFIO group file or VFIO device file
  */
 bool vfio_file_is_valid(struct file *file)
 {
-	return vfio_group_from_file(file);
+	return vfio_group_from_file(file) ||
+	       vfio_device_from_file(file);
 }
 EXPORT_SYMBOL_GPL(vfio_file_is_valid);
 
@@ -1188,15 +1199,36 @@  EXPORT_SYMBOL_GPL(vfio_file_is_valid);
  */
 bool vfio_file_enforced_coherent(struct file *file)
 {
-	struct vfio_group *group = vfio_group_from_file(file);
+	struct vfio_group *group;
+	struct vfio_device *device;
 
+	group = vfio_group_from_file(file);
 	if (group)
 		return vfio_group_enforced_coherent(group);
 
+	device = vfio_device_from_file(file);
+	if (device)
+		return device_iommu_capable(device->dev,
+					    IOMMU_CAP_ENFORCE_CACHE_COHERENCY);
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(vfio_file_enforced_coherent);
 
+static void vfio_device_file_set_kvm(struct file *file, struct kvm *kvm)
+{
+	struct vfio_device_file *df = file->private_data;
+
+	/*
+	 * The kvm is first recorded in the vfio_device_file, and will
+	 * be propagated to vfio_device::kvm when the file is bound to
+	 * iommufd successfully in the vfio device cdev path.
+	 */
+	spin_lock(&df->kvm_ref_lock);
+	df->kvm = kvm;
+	spin_unlock(&df->kvm_ref_lock);
+}
+
 /**
  * vfio_file_set_kvm - Link a kvm with VFIO drivers
  * @file: VFIO group file or VFIO device file
@@ -1205,10 +1237,14 @@  EXPORT_SYMBOL_GPL(vfio_file_enforced_coherent);
  */
 void vfio_file_set_kvm(struct file *file, struct kvm *kvm)
 {
-	struct vfio_group *group = vfio_group_from_file(file);
+	struct vfio_group *group;
 
+	group = vfio_group_from_file(file);
 	if (group)
 		vfio_group_set_kvm(group, kvm);
+
+	if (vfio_device_from_file(file))
+		vfio_device_file_set_kvm(file, kvm);
 }
 EXPORT_SYMBOL_GPL(vfio_file_set_kvm);
 
@@ -1221,10 +1257,17 @@  EXPORT_SYMBOL_GPL(vfio_file_set_kvm);
  */
 bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
 {
-	struct vfio_group *group = vfio_group_from_file(file);
+	struct vfio_group *group;
+	struct vfio_device *vdev;
 
+	group = vfio_group_from_file(file);
 	if (group)
 		return vfio_group_has_dev(group, device);
+
+	vdev = vfio_device_from_file(file);
+	if (device)
+		return vdev == device;
+
 	return false;
 }
 EXPORT_SYMBOL_GPL(vfio_file_has_dev);