Re: [PATCH v3 06/12] vfio: Refine vfio file kAPIs for vfio PCI hot reset

Eric Auger
2023-04-05T08:28:41Z

Hi Yi,
On 4/1/23 16:44, Yi Liu wrote:
> This prepares vfio core to accept vfio device file from the vfio PCI
> hot reset path. vfio_file_is_group() is still kept for KVM usage.
>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Tested-by: Yanting Jiang <yanting.jiang@intel.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
> drivers/vfio/group.c | 32 ++++++++++++++------------------
> drivers/vfio/pci/vfio_pci_core.c | 4 ++--
> drivers/vfio/vfio.h | 2 ++
> drivers/vfio/vfio_main.c | 29 +++++++++++++++++++++++++++++
> include/linux/vfio.h | 1 +
> 5 files changed, 48 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
> index 27d5ba7cf9dc..d0c95d033605 100644
> --- a/drivers/vfio/group.c
> +++ b/drivers/vfio/group.c
> @@ -745,6 +745,15 @@ bool vfio_device_has_container(struct vfio_device *device)
> return device->group->container;
> }
>
> +struct vfio_group *vfio_group_from_file(struct file *file)
> +{
> + struct vfio_group *group = file->private_data;
> +
> + if (file->f_op != &vfio_group_fops)
> + return NULL;
> + return group;
> +}
> +
> /**
> * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
> * @file: VFIO group file
> @@ -755,13 +764,13 @@ bool vfio_device_has_container(struct vfio_device *device)
> */
> struct iommu_group *vfio_file_iommu_group(struct file *file)
> {
> - struct vfio_group *group = file->private_data;
> + struct vfio_group *group = vfio_group_from_file(file);
> struct iommu_group *iommu_group = NULL;
>
> if (!IS_ENABLED(CONFIG_SPAPR_TCE_IOMMU))
> return NULL;
>
> - if (!vfio_file_is_group(file))
> + if (!group)
> return NULL;
>
> mutex_lock(&group->group_lock);
> @@ -775,12 +784,12 @@ struct iommu_group *vfio_file_iommu_group(struct file *file)
> EXPORT_SYMBOL_GPL(vfio_file_iommu_group);
>
> /**
> - * vfio_file_is_group - True if the file is usable with VFIO aPIS
> + * vfio_file_is_group - True if the file is a vfio group file
> * @file: VFIO group file
> */
> bool vfio_file_is_group(struct file *file)
> {
> - return file->f_op == &vfio_group_fops;
> + return vfio_group_from_file(file);
> }
> EXPORT_SYMBOL_GPL(vfio_file_is_group);
>
> @@ -842,23 +851,10 @@ void vfio_file_set_kvm(struct file *file, struct kvm *kvm)
> }
> EXPORT_SYMBOL_GPL(vfio_file_set_kvm);
>
> -/**
> - * vfio_file_has_dev - True if the VFIO file is a handle for device
> - * @file: VFIO file to check
> - * @device: Device that must be part of the file
> - *
> - * Returns true if given file has permission to manipulate the given device.
> - */
> -bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
> +bool vfio_group_has_dev(struct vfio_group *group, struct vfio_device *device)
> {
> - struct vfio_group *group = file->private_data;
> -
> - if (!vfio_file_is_group(file))
> - return false;
> -
> return group == device->group;
> }
> -EXPORT_SYMBOL_GPL(vfio_file_has_dev);
>
> static char *vfio_devnode(const struct device *dev, umode_t *mode)
> {
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index b68fcba67a4b..2a510b71edcb 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1308,8 +1308,8 @@ vfio_pci_ioctl_pci_hot_reset_groups(struct vfio_pci_core_device *vdev,
> break;
> }
>
> - /* Ensure the FD is a vfio group FD.*/
> - if (!vfio_file_is_group(file)) {
> + /* Ensure the FD is a vfio FD. vfio group or vfio device */
it is a bit strange to update the comment here and in the other places
in this patch whereas file_is_valid still sticks to group file check
By the way I would simply remove the comment which does not bring much
> + if (!vfio_file_is_valid(file)) {
> fput(file);
> ret = -EINVAL;
> break;
> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
> index 7b19c621e0e6..c0aeea24fbd6 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -84,6 +84,8 @@ void vfio_device_group_unregister(struct vfio_device *device);
> int vfio_device_group_use_iommu(struct vfio_device *device);
> void vfio_device_group_unuse_iommu(struct vfio_device *device);
> void vfio_device_group_close(struct vfio_device *device);
> +struct vfio_group *vfio_group_from_file(struct file *file);
> +bool vfio_group_has_dev(struct vfio_group *group, struct vfio_device *device);
> bool vfio_device_has_container(struct vfio_device *device);
> int __init vfio_group_init(void);
> void vfio_group_cleanup(void);
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index 89497c933490..fe7446805afd 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -1154,6 +1154,35 @@ const struct file_operations vfio_device_fops = {
> .mmap = vfio_device_fops_mmap,
> };
>
> +/**
> + * vfio_file_is_valid - True if the file is valid vfio file
> + * @file: VFIO group file or VFIO device file
I wonder if you shouldn't squash with next patch tbh.
> + */
> +bool vfio_file_is_valid(struct file *file)
> +{
> + return vfio_group_from_file(file);
> +}
> +EXPORT_SYMBOL_GPL(vfio_file_is_valid);
> +
> +/**
> + * vfio_file_has_dev - True if the VFIO file is a handle for device
> + * @file: VFIO file to check
> + * @device: Device that must be part of the file
> + *
> + * Returns true if given file has permission to manipulate the given device.
> + */
> +bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
> +{
> + struct vfio_group *group;
> +
> + group = vfio_group_from_file(file);
> + if (!group)
> + return false;
> +
> + return vfio_group_has_dev(group, device);
> +}
> +EXPORT_SYMBOL_GPL(vfio_file_has_dev);
> +
> /*
> * Sub-module support
> */
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 97a1174b922f..f8fb9ab25188 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -258,6 +258,7 @@ int vfio_mig_get_next_state(struct vfio_device *device,
> */
> struct iommu_group *vfio_file_iommu_group(struct file *file);
> bool vfio_file_is_group(struct file *file);
> +bool vfio_file_is_valid(struct file *file);
> bool vfio_file_enforced_coherent(struct file *file);
> void vfio_file_set_kvm(struct file *file, struct kvm *kvm);
> bool vfio_file_has_dev(struct file *file, struct vfio_device *device);
Eric