vfio: Compile vfio_group infrastructure optionally

vfio_group is not needed for vfio device cdev, so with vfio device cdev
introduced, the vfio_group infrastructures can be compiled out if only
cdev is needed.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-26-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/iommu/iommufd/Kconfig b/drivers/iommu/iommufd/Kconfig
index ada693e..99d4b07 100644 (file)
--- 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_GROUP && !VFIO_CONTAINER
+       default VFIO_GROUP && !VFIO_CONTAINER
        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 26f18d9..6bda6db 100644 (file)
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -4,6 +4,8 @@ menuconfig VFIO
        select IOMMU_API
        depends on IOMMUFD || !IOMMUFD
        select INTERVAL_TREE
+       select VFIO_GROUP if SPAPR_TCE_IOMMU || IOMMUFD=n
+       select VFIO_DEVICE_CDEV if !VFIO_GROUP
        select VFIO_CONTAINER if IOMMUFD=n
        help
          VFIO provides a framework for secure userspace device drivers.
@@ -15,6 +17,7 @@ if VFIO
 config VFIO_DEVICE_CDEV
        bool "Support for the VFIO cdev /dev/vfio/devices/vfioX"
        depends on IOMMUFD && !SPAPR_TCE_IOMMU
+       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
@@ -24,9 +27,20 @@ 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
@@ -48,6 +62,7 @@ endif
 
 config VFIO_NOIOMMU
        bool "VFIO No-IOMMU support"
+       depends on VFIO_GROUP
        help
          VFIO is built on the ability to isolate devices using the IOMMU.
          Only with an IOMMU can userspace access to DMA capable devices be

diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 87ccb16..c82ea03 100644 (file)
--- 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 8353774..307e3f2 100644 (file)
--- 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;
@@ -111,6 +118,82 @@ static inline bool vfio_device_is_noiommu(struct vfio_device *vdev)
        return IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
               vdev->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 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_df_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_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 bool vfio_device_is_noiommu(struct vfio_device *vdev)
+{
+       return false;
+}
+#endif /* CONFIG_VFIO_GROUP */
 
 #if IS_ENABLED(CONFIG_VFIO_CONTAINER)
 /**
@@ -351,12 +434,6 @@ 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 d6228c8..5a1dee9 100644 (file)
--- 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)
@@ -284,12 +286,29 @@ 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);
 bool vfio_file_is_group(struct file *file);
+bool vfio_file_has_dev(struct file *file, struct vfio_device *device);
+#else
+static inline struct iommu_group *vfio_file_iommu_group(struct file *file)
+{
+       return NULL;
+}
+
+static inline bool vfio_file_is_group(struct file *file)
+{
+       return false;
+}
+
+static inline bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
+{
+       return false;
+}
+#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);
-bool vfio_file_has_dev(struct file *file, struct vfio_device *device);
 
 #define VFIO_PIN_PAGES_MAX_ENTRIES     (PAGE_SIZE/sizeof(unsigned long))