On Mon, 27 Mar 2023 02:40:46 -0700
Yi Liu <yi.l.liu@xxxxxxxxx> wrote:
> group code is not needed for vfio device cdev, so with vfio device cdev
> introduced, the group infrastructures can be compiled out if only cdev
> is needed.
>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Tested-by: Terrence Xu <terrence.xu@xxxxxxxxx>
> Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> ---
> drivers/iommu/iommufd/Kconfig | 4 +-
> drivers/vfio/Kconfig | 16 ++++-
> drivers/vfio/Makefile | 2 +-
> drivers/vfio/vfio.h | 111 ++++++++++++++++++++++++++++++++--
> include/linux/vfio.h | 13 +++-
> 5 files changed, 134 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/iommu/iommufd/Kconfig b/drivers/iommu/iommufd/Kconfig
> index ada693ea51a7..1946eed1826a 100644
> --- a/drivers/iommu/iommufd/Kconfig
> +++ b/drivers/iommu/iommufd/Kconfig
> @@ -14,8 +14,8 @@ config IOMMUFD
> if IOMMUFD
> config IOMMUFD_VFIO_CONTAINER
> bool "IOMMUFD provides the VFIO container /dev/vfio/vfio"
> - depends on VFIO && !VFIO_CONTAINER
> - default VFIO && !VFIO_CONTAINER
> + depends on VFIO && VFIO_GROUP && !VFIO_CONTAINER
> + default VFIO && VFIO_GROUP && !VFIO_CONTAINER
Shouldn't these simply replace VFIO with VFIO_GROUP since VFIO_GROUP
necessarily depends on VFIO?
> help
> IOMMUFD will provide /dev/vfio/vfio instead of VFIO. This relies on
> IOMMUFD providing compatibility emulation to give the same ioctls.
> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
> index e2105b4dac2d..0942a19601a2 100644
> --- a/drivers/vfio/Kconfig
> +++ b/drivers/vfio/Kconfig
> @@ -4,7 +4,9 @@ menuconfig VFIO
> select IOMMU_API
> depends on IOMMUFD || !IOMMUFD
> select INTERVAL_TREE
> - select VFIO_CONTAINER if IOMMUFD=n
> + select VFIO_GROUP if SPAPR_TCE_IOMMU || !IOMMUFD
This needs to be IOMMUFD=n or else VFIO_GROUP cannot be unset when
IOMMUFD=m
> + select VFIO_DEVICE_CDEV if !VFIO_GROUP
> + select VFIO_CONTAINER if IOMMUFD=n && VFIO_GROUP
The fact that CONTAINER depends on GROUP seems to be sufficient that we
don't need GROUP here. Thanks,
Alex
> help
> VFIO provides a framework for secure userspace device drivers.
> See Documentation/driver-api/vfio.rst for more details.
> @@ -15,6 +17,7 @@ if VFIO
> config VFIO_DEVICE_CDEV
> bool "Support for the VFIO cdev /dev/vfio/devices/vfioX"
> depends on IOMMUFD
> + default !VFIO_GROUP
> help
> The VFIO device cdev is another way for userspace to get device
> access. Userspace gets device fd by opening device cdev under
> @@ -23,9 +26,20 @@ config VFIO_DEVICE_CDEV
>
> If you don't know what to do here, say N.
>
> +config VFIO_GROUP
> + bool "Support for the VFIO group /dev/vfio/$group_id"
> + default y
> + help
> + VFIO group support provides the traditional model for accessing
> + devices through VFIO and is used by the majority of userspace
> + applications and drivers making use of VFIO.
> +
> + If you don't know what to do here, say Y.
> +
> config VFIO_CONTAINER
> bool "Support for the VFIO container /dev/vfio/vfio"
> select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64)
> + depends on VFIO_GROUP
> default y
> help
> The VFIO container is the classic interface to VFIO for establishing
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index 245394aeb94b..57c3515af606 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -2,9 +2,9 @@
> obj-$(CONFIG_VFIO) += vfio.o
>
> vfio-y += vfio_main.o \
> - group.o \
> iova_bitmap.o
> vfio-$(CONFIG_VFIO_DEVICE_CDEV) += device_cdev.o
> +vfio-$(CONFIG_VFIO_GROUP) += group.o
> vfio-$(CONFIG_IOMMUFD) += iommufd.o
> vfio-$(CONFIG_VFIO_CONTAINER) += container.o
> vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
> index c199e410db18..9c7a238ec8dd 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -36,6 +36,12 @@ vfio_allocate_device_file(struct vfio_device *device);
>
> extern const struct file_operations vfio_device_fops;
>
> +#ifdef CONFIG_VFIO_NOIOMMU
> +extern bool vfio_noiommu __read_mostly;
> +#else
> +enum { vfio_noiommu = false };
> +#endif
> +
> enum vfio_group_type {
> /*
> * Physical device with IOMMU backing.
> @@ -60,6 +66,7 @@ enum vfio_group_type {
> VFIO_NO_IOMMU,
> };
>
> +#if IS_ENABLED(CONFIG_VFIO_GROUP)
> struct vfio_group {
> struct device dev;
> struct cdev cdev;
> @@ -113,6 +120,104 @@ static inline void vfio_device_set_noiommu(struct vfio_device *device)
> device->noiommu = IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
> device->group->type == VFIO_NO_IOMMU;
> }
> +#else
> +struct vfio_group;
> +
> +static inline int vfio_device_block_group(struct vfio_device *device)
> +{
> + return 0;
> +}
> +
> +static inline void vfio_device_unblock_group(struct vfio_device *device)
> +{
> +}
> +
> +static inline int vfio_device_set_group(struct vfio_device *device,
> + enum vfio_group_type type)
> +{
> + return 0;
> +}
> +
> +static inline void vfio_device_remove_group(struct vfio_device *device)
> +{
> +}
> +
> +static inline void vfio_device_group_register(struct vfio_device *device)
> +{
> +}
> +
> +static inline void vfio_device_group_unregister(struct vfio_device *device)
> +{
> +}
> +
> +static inline bool vfio_device_group_uses_container(struct vfio_device_file *df)
> +{
> + return false;
> +}
> +
> +static inline int vfio_device_group_use_iommu(struct vfio_device *device)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static inline void vfio_device_group_unuse_iommu(struct vfio_device *device)
> +{
> +}
> +
> +static inline void vfio_device_group_close(struct vfio_device_file *df)
> +{
> +}
> +
> +static inline struct vfio_group *vfio_group_from_file(struct file *file)
> +{
> + return NULL;
> +}
> +
> +static inline bool vfio_group_has_dev(struct vfio_group *group,
> + struct vfio_device *device)
> +{
> + return false;
> +}
> +
> +static inline bool vfio_group_enforced_coherent(struct vfio_group *group)
> +{
> + return true;
> +}
> +
> +static inline void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
> +{
> +}
> +
> +static inline bool vfio_device_has_container(struct vfio_device *device)
> +{
> + return false;
> +}
> +
> +static inline int __init vfio_group_init(void)
> +{
> + return 0;
> +}
> +
> +static inline void vfio_group_cleanup(void)
> +{
> +}
> +
> +static inline void vfio_device_set_noiommu(struct vfio_device *device)
> +{
> + struct iommu_group *iommu_group;
> +
> + device->noiommu = false;
> +
> + if (!IS_ENABLED(CONFIG_VFIO_NOIOMMU) || !vfio_noiommu)
> + return;
> +
> + iommu_group = iommu_group_get(device->dev);
> + if (iommu_group)
> + iommu_group_put(iommu_group);
> + else
> + device->noiommu = true;
> +}
> +#endif /* CONFIG_VFIO_GROUP */
>
> #if IS_ENABLED(CONFIG_VFIO_CONTAINER)
> /**
> @@ -356,12 +461,6 @@ static inline void vfio_virqfd_exit(void)
> }
> #endif
>
> -#ifdef CONFIG_VFIO_NOIOMMU
> -extern bool vfio_noiommu __read_mostly;
> -#else
> -enum { vfio_noiommu = false };
> -#endif
> -
> #ifdef CONFIG_HAVE_KVM
> void _vfio_device_get_kvm_safe(struct vfio_device *device, struct kvm *kvm);
> void vfio_device_put_kvm(struct vfio_device *device);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 8719ec2adbbb..1367605d617c 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -43,7 +43,11 @@ struct vfio_device {
> */
> const struct vfio_migration_ops *mig_ops;
> const struct vfio_log_ops *log_ops;
> +#if IS_ENABLED(CONFIG_VFIO_GROUP)
> struct vfio_group *group;
> + struct list_head group_next;
> + struct list_head iommu_entry;
> +#endif
> struct vfio_device_set *dev_set;
> struct list_head dev_set_list;
> unsigned int migration_flags;
> @@ -58,8 +62,6 @@ struct vfio_device {
> refcount_t refcount; /* user count on registered device*/
> unsigned int open_count;
> struct completion comp;
> - struct list_head group_next;
> - struct list_head iommu_entry;
> struct iommufd_access *iommufd_access;
> void (*put_kvm)(struct kvm *kvm);
> #if IS_ENABLED(CONFIG_IOMMUFD)
> @@ -270,7 +272,14 @@ int vfio_mig_get_next_state(struct vfio_device *device,
> /*
> * External user API
> */
> +#if IS_ENABLED(CONFIG_VFIO_GROUP)
> struct iommu_group *vfio_file_iommu_group(struct file *file);
> +#else
> +static inline struct iommu_group *vfio_file_iommu_group(struct file *file)
> +{
> + return NULL;
> +}
> +#endif
> 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);
