Hi Yi,
On 1/17/23 14:49, Yi Liu wrote:
> This makes the vfio file kAPIs to accepte vfio device files, also a
> preparation for vfio device cdev support.
>
> Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> ---
> drivers/vfio/vfio.h | 1 +
> drivers/vfio/vfio_main.c | 51 ++++++++++++++++++++++++++++++++++++----
> 2 files changed, 48 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
> index ef5de2872983..53af6e3ea214 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -18,6 +18,7 @@ struct vfio_container;
>
> struct vfio_device_file {
> struct vfio_device *device;
> + 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 1aedfbd15ca0..dc08d5dd62cc 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -1119,13 +1119,23 @@ 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 usable with VFIO aPIS
> * @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);
>
> @@ -1140,15 +1150,37 @@ 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;
> + struct vfio_device *device = df->device;
> +
> + /*
> + * The kvm is first recorded in the df, and will be propagated
> + * to vfio_device::kvm when the file binds iommufd successfully in
> + * the vfio device cdev path.
> + */
> + mutex_lock(&device->dev_set->lock);
it is not totally obvious to me why the
device->dev_set->lock needs to be held here and why that lock in particular. Isn't supposed to protect the vfio_device_set. The header just mentions
"the VFIO core will provide a lock that is held around open_device()/close_device() for all devices in the set."
> + df->kvm = kvm;
> + mutex_unlock(&device->dev_set->lock);
> +}
> +
> /**
> * vfio_file_set_kvm - Link a kvm with VFIO drivers
> * @file: VFIO group file or device file
> @@ -1157,10 +1189,14 @@ 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);
>
> @@ -1173,10 +1209,17 @@ 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);
Thanks
Eric
