Re: [PATCH 12/14] vfio/mdev: consolidate all the available_instance sysfs into the core code

[Eric Farman <farman@linux.ibm.com>]

On Fri, 2022-09-23 at 11:26 +0200, Christoph Hellwig wrote:
> Every driver just print a number, simply add a method to the
> mdev_driver
> to return it and provide a standard sysfs show function.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>

Reviewed-by: Eric Farman <farman@linux.ibm.com>

> ---
>  .../driver-api/vfio-mediated-device.rst       |  3 +-
>  drivers/gpu/drm/i915/gvt/gvt.h                |  1 -
>  drivers/gpu/drm/i915/gvt/kvmgt.c              | 34 +++++++++------
>  drivers/gpu/drm/i915/gvt/vgpu.c               | 41 ++---------------
> --
>  drivers/s390/cio/vfio_ccw_ops.c               | 14 ++-----
>  drivers/s390/crypto/vfio_ap_ops.c             | 16 ++------
>  drivers/vfio/mdev/mdev_sysfs.c                | 11 +++++
>  include/linux/mdev.h                          |  2 +
>  samples/vfio-mdev/mbochs.c                    | 10 ++---
>  samples/vfio-mdev/mdpy.c                      |  9 ++--
>  samples/vfio-mdev/mtty.c                      | 16 ++------
>  11 files changed, 55 insertions(+), 102 deletions(-)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index dcd1231a6fa84..558bd7ebced86 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -103,6 +103,7 @@ structure to represent a mediated device's
> driver::
>       struct mdev_driver {
>              int  (*probe)  (struct mdev_device *dev);
>              void (*remove) (struct mdev_device *dev);
> +            unsigned int (*get_available)(struct mdev_type *mtype);
>              const struct attribute * const *types_attrs;
>              struct device_driver    driver;
>       };
> @@ -207,7 +208,7 @@ Directories and files under the sysfs for Each
> Physical Device
>  
>  * available_instances
>  
> -  This attribute should show the number of devices of type <type-id>
> that can be
> +  This attribute shows the number of devices of type <type-id> that
> can be
>    created.
>  
>  * [device]
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h
> b/drivers/gpu/drm/i915/gvt/gvt.h
> index db182066d56c9..dbf8d7470b2c1 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -314,7 +314,6 @@ struct intel_vgpu_type {
>         struct mdev_type type;
>         char name[16];
>         const struct intel_vgpu_config *conf;
> -       unsigned int avail_instance;
>  };
>  
>  struct intel_gvt {
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 08fe7458b3610..d8be21a3931d9 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -113,16 +113,6 @@ static void kvmgt_page_track_flush_slot(struct
> kvm *kvm,
>                 struct kvm_memory_slot *slot,
>                 struct kvm_page_track_notifier_node *node);
>  
> -static ssize_t available_instances_show(struct mdev_type *mtype,
> -                                       struct mdev_type_attribute
> *attr,
> -                                       char *buf)
> -{
> -       struct intel_vgpu_type *type =
> -               container_of(mtype, struct intel_vgpu_type, type);
> -
> -       return sprintf(buf, "%u\n", type->avail_instance);
> -}
> -
>  static ssize_t description_show(struct mdev_type *mtype,
>                                 struct mdev_type_attribute *attr,
> char *buf)
>  {
> @@ -138,11 +128,9 @@ static ssize_t description_show(struct mdev_type
> *mtype,
>                        type->conf->weight);
>  }
>  
> -static MDEV_TYPE_ATTR_RO(available_instances);
>  static MDEV_TYPE_ATTR_RO(description);
>  
>  static const struct attribute *gvt_type_attrs[] = {
> -       &mdev_type_attr_available_instances.attr,
>         &mdev_type_attr_description.attr,
>         NULL,
>  };
> @@ -1532,6 +1520,27 @@ static void intel_vgpu_remove(struct
> mdev_device *mdev)
>         vfio_put_device(&vgpu->vfio_device);
>  }
>  
> +static unsigned int intel_vgpu_get_available(struct mdev_type
> *mtype)
> +{
> +       struct intel_vgpu_type *type =
> +               container_of(mtype, struct intel_vgpu_type, type);
> +       struct intel_gvt *gvt = kdev_to_i915(mtype->parent->dev)-
> >gvt;
> +       unsigned int low_gm_avail, high_gm_avail, fence_avail;
> +
> +       mutex_lock(&gvt->lock);
> +       low_gm_avail = gvt_aperture_sz(gvt) - HOST_LOW_GM_SIZE -
> +               gvt->gm.vgpu_allocated_low_gm_size;
> +       high_gm_avail = gvt_hidden_sz(gvt) - HOST_HIGH_GM_SIZE -
> +               gvt->gm.vgpu_allocated_high_gm_size;
> +       fence_avail = gvt_fence_sz(gvt) - HOST_FENCE -
> +               gvt->fence.vgpu_allocated_fence_num;
> +       mutex_unlock(&gvt->lock);
> +
> +       return min3(low_gm_avail / type->conf->low_mm,
> +                   high_gm_avail / type->conf->high_mm,
> +                   fence_avail / type->conf->fence);
> +}
> +
>  static struct mdev_driver intel_vgpu_mdev_driver = {
>         .device_api     = VFIO_DEVICE_API_PCI_STRING,
>         .driver = {
> @@ -1541,6 +1550,7 @@ static struct mdev_driver
> intel_vgpu_mdev_driver = {
>         },
>         .probe          = intel_vgpu_probe,
>         .remove         = intel_vgpu_remove,
> +       .get_available  = intel_vgpu_get_available,
>         .types_attrs    = gvt_type_attrs,
>  };
>  
> diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c
> b/drivers/gpu/drm/i915/gvt/vgpu.c
> index 8fa06d00fd4b9..148bf5d6c4fd4 100644
> --- a/drivers/gpu/drm/i915/gvt/vgpu.c
> +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
> @@ -129,11 +129,11 @@ int intel_gvt_init_vgpu_types(struct intel_gvt
> *gvt)
>                 sprintf(gvt->types[i].name, "GVTg_V%u_%s",
>                         GRAPHICS_VER(gvt->gt->i915) == 8 ? 4 : 5,
> conf->name);
>                 gvt->types->conf = conf;
> -               gvt->types[i].avail_instance = min(low_avail / conf-
> >low_mm,
> -                                                  high_avail / conf-
> >high_mm);
>  
>                 gvt_dbg_core("type[%d]: %s avail %u low %u high %u
> fence %u weight %u res %s\n",
> -                            i, gvt->types[i].name, gvt-
> >types[i].avail_instance,
> +                            i, gvt->types[i].name,
> +                            min(low_avail / conf->low_mm,
> +                                high_avail / conf->high_mm),
>                              conf->low_mm, conf->high_mm, conf-
> >fence,
>                              conf->weight, vgpu_edid_str(conf-
> >edid));
>  
> @@ -157,36 +157,6 @@ void intel_gvt_clean_vgpu_types(struct intel_gvt
> *gvt)
>         kfree(gvt->types);
>  }
>  
> -static void intel_gvt_update_vgpu_types(struct intel_gvt *gvt)
> -{
> -       int i;
> -       unsigned int low_gm_avail, high_gm_avail, fence_avail;
> -       unsigned int low_gm_min, high_gm_min, fence_min;
> -
> -       /* Need to depend on maxium hw resource size but keep on
> -        * static config for now.
> -        */
> -       low_gm_avail = gvt_aperture_sz(gvt) - HOST_LOW_GM_SIZE -
> -               gvt->gm.vgpu_allocated_low_gm_size;
> -       high_gm_avail = gvt_hidden_sz(gvt) - HOST_HIGH_GM_SIZE -
> -               gvt->gm.vgpu_allocated_high_gm_size;
> -       fence_avail = gvt_fence_sz(gvt) - HOST_FENCE -
> -               gvt->fence.vgpu_allocated_fence_num;
> -
> -       for (i = 0; i < gvt->num_types; i++) {
> -               low_gm_min = low_gm_avail / gvt->types[i].conf-
> >low_mm;
> -               high_gm_min = high_gm_avail / gvt->types[i].conf-
> >high_mm;
> -               fence_min = fence_avail / gvt->types[i].conf->fence;
> -               gvt->types[i].avail_instance = min(min(low_gm_min,
> high_gm_min),
> -                                                  fence_min);
> -
> -               gvt_dbg_core("update type[%d]: %s avail %u low %u
> high %u fence %u\n",
> -                      i, gvt->types[i].name,
> -                      gvt->types[i].avail_instance, gvt-
> >types[i].conf->low_mm,
> -                      gvt->types[i].conf->high_mm, gvt-
> >types[i].conf->fence);
> -       }
> -}
> -
>  /**
>   * intel_gvt_active_vgpu - activate a virtual GPU
>   * @vgpu: virtual GPU
> @@ -281,10 +251,6 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu
> *vgpu)
>         intel_vgpu_clean_mmio(vgpu);
>         intel_vgpu_dmabuf_cleanup(vgpu);
>         mutex_unlock(&vgpu->vgpu_lock);
> -
> -       mutex_lock(&gvt->lock);
> -       intel_gvt_update_vgpu_types(gvt);
> -       mutex_unlock(&gvt->lock);
>  }
>  
>  #define IDLE_VGPU_IDR 0
> @@ -414,7 +380,6 @@ int intel_gvt_create_vgpu(struct intel_vgpu
> *vgpu,
>         if (ret)
>                 goto out_clean_sched_policy;
>  
> -       intel_gvt_update_vgpu_types(gvt);
>         intel_gvt_update_reg_whitelist(vgpu);
>         mutex_unlock(&gvt->lock);
>         return 0;
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
> b/drivers/s390/cio/vfio_ccw_ops.c
> index 394aab60dbd0a..559ca18055928 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -44,20 +44,12 @@ static void vfio_ccw_dma_unmap(struct vfio_device
> *vdev, u64 iova, u64 length)
>         vfio_ccw_mdev_reset(private);
>  }
>  
> -static ssize_t available_instances_show(struct mdev_type *mtype,
> -                                       struct mdev_type_attribute
> *attr,
> -                                       char *buf)
> +static unsigned int vfio_ccw_get_available(struct mdev_type *mtype)
>  {
>         struct vfio_ccw_private *private = dev_get_drvdata(mtype-
> >parent->dev);
>  
> -       return sprintf(buf, "%d\n", atomic_read(&private->avail));
> +       return atomic_read(&private->avail);
>  }
> -static MDEV_TYPE_ATTR_RO(available_instances);
> -
> -static const struct attribute *mdev_types_attrs[] = {
> -       &mdev_type_attr_available_instances.attr,
> -       NULL,
> -};
>  
>  static int vfio_ccw_mdev_init_dev(struct vfio_device *vdev)
>  {
> @@ -620,5 +612,5 @@ struct mdev_driver vfio_ccw_mdev_driver = {
>         },
>         .probe = vfio_ccw_mdev_probe,
>         .remove = vfio_ccw_mdev_remove,
> -       .types_attrs = mdev_types_attrs,
> +       .get_available = vfio_ccw_get_available,
>  };
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index 5d8dd7e837f3d..8606f5d75188c 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -790,21 +790,11 @@ static void vfio_ap_mdev_remove(struct
> mdev_device *mdev)
>         vfio_put_device(&matrix_mdev->vdev);
>  }
>  
> -static ssize_t available_instances_show(struct mdev_type *mtype,
> -                                       struct mdev_type_attribute
> *attr,
> -                                       char *buf)
> +static unsigned int vfio_ap_mdev_get_available(struct mdev_type
> *mtype)
>  {
> -       return sprintf(buf, "%d\n",
> -                      atomic_read(&matrix_dev-
> >available_instances));
> +       return atomic_read(&matrix_dev->available_instances);
>  }
>  
> -static MDEV_TYPE_ATTR_RO(available_instances);
> -
> -static const struct attribute *vfio_ap_mdev_type_attrs[] = {
> -       &mdev_type_attr_available_instances.attr,
> -       NULL,
> -};
> -
>  #define MDEV_SHARING_ERR "Userspace may not re-assign queue
> %02lx.%04lx " \
>                          "already assigned to %s"
>  
> @@ -1790,7 +1780,7 @@ static struct mdev_driver vfio_ap_matrix_driver
> = {
>         },
>         .probe = vfio_ap_mdev_probe,
>         .remove = vfio_ap_mdev_remove,
> -       .types_attrs = vfio_ap_mdev_type_attrs,
> +       .get_available = vfio_ap_mdev_get_available,
>  };
>  
>  int vfio_ap_mdev_register(void)
> diff --git a/drivers/vfio/mdev/mdev_sysfs.c
> b/drivers/vfio/mdev/mdev_sysfs.c
> index 34583e6a97f27..b7f87c3eda5ea 100644
> --- a/drivers/vfio/mdev/mdev_sysfs.c
> +++ b/drivers/vfio/mdev/mdev_sysfs.c
> @@ -90,10 +90,21 @@ static ssize_t name_show(struct mdev_type *mtype,
>  
>  static MDEV_TYPE_ATTR_RO(name);
>  
> +static ssize_t available_instances_show(struct mdev_type *mtype,
> +                                       struct mdev_type_attribute
> *attr,
> +                                       char *buf)
> +{
> +       struct mdev_driver *drv = mtype->parent->mdev_driver;
> +
> +       return sysfs_emit(buf, "%u\n", drv->get_available(mtype));
> +}
> +static MDEV_TYPE_ATTR_RO(available_instances);
> +
>  static struct attribute *mdev_types_core_attrs[] = {
>         &mdev_type_attr_create.attr,
>         &mdev_type_attr_device_api.attr,
>         &mdev_type_attr_name.attr,
> +       &mdev_type_attr_available_instances.attr,
>         NULL,
>  };
>  
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 4bb8a58b577b3..d39e08a1824c6 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -72,6 +72,7 @@ struct mdev_type_attribute {
>   * @device_api: string to return for the device_api sysfs
>   * @probe: called when new device created
>   * @remove: called when device removed
> + * @get_available: Return the max number of instances that can be
> created
>   * @types_attrs: attributes to the type kobjects.
>   * @driver: device driver structure
>   **/
> @@ -79,6 +80,7 @@ struct mdev_driver {
>         const char *device_api;
>         int (*probe)(struct mdev_device *dev);
>         void (*remove)(struct mdev_device *dev);
> +       unsigned int (*get_available)(struct mdev_type *mtype);
>         const struct attribute * const *types_attrs;
>         struct device_driver driver;
>  };
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index 0b7585f16d8ab..6c2cbc4e25ca9 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -1361,21 +1361,16 @@ static ssize_t description_show(struct
> mdev_type *mtype,
>  }
>  static MDEV_TYPE_ATTR_RO(description);
>  
> -static ssize_t available_instances_show(struct mdev_type *mtype,
> -                                       struct mdev_type_attribute
> *attr,
> -                                       char *buf)
> +static unsigned int mbochs_get_available(struct mdev_type *mtype)
>  {
>         struct mbochs_type *type =
>                 container_of(mtype, struct mbochs_type, type);
> -       int count = atomic_read(&mbochs_avail_mbytes) / type->mbytes;
>  
> -       return sprintf(buf, "%d\n", count);
> +       return atomic_read(&mbochs_avail_mbytes) / type->mbytes;
>  }
> -static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *mdev_types_attrs[] = {
>         &mdev_type_attr_description.attr,
> -       &mdev_type_attr_available_instances.attr,
>         NULL,
>  };
>  
> @@ -1399,6 +1394,7 @@ static struct mdev_driver mbochs_driver = {
>         },
>         .probe = mbochs_probe,
>         .remove = mbochs_remove,
> +       .get_available = mbochs_get_available,
>         .types_attrs = mdev_types_attrs,
>  };
>  
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index 90c6fed200b19..d1c835c9cabf2 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -671,17 +671,13 @@ static ssize_t description_show(struct
> mdev_type *mtype,
>  }
>  static MDEV_TYPE_ATTR_RO(description);
>  
> -static ssize_t available_instances_show(struct mdev_type *mtype,
> -                                       struct mdev_type_attribute
> *attr,
> -                                       char *buf)
> +static unsigned int mdpy_get_available(struct mdev_type *mtype)
>  {
> -       return sprintf(buf, "%d\n", max_devices - mdpy_count);
> +       return max_devices - mdpy_count;
>  }
> -static MDEV_TYPE_ATTR_RO(available_instances);
>  
>  static const struct attribute *mdev_types_attrs[] = {
>         &mdev_type_attr_description.attr,
> -       &mdev_type_attr_available_instances.attr,
>         NULL,
>  };
>  
> @@ -704,6 +700,7 @@ static struct mdev_driver mdpy_driver = {
>         },
>         .probe = mdpy_probe,
>         .remove = mdpy_remove,
> +       .get_available = mdpy_get_available,
>         .types_attrs = mdev_types_attrs,
>  };
>  
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index eab1b4442a96e..e72085fc13763 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -1256,23 +1256,13 @@ static const struct attribute_group
> *mdev_dev_groups[] = {
>         NULL,
>  };
>  
> -static ssize_t available_instances_show(struct mdev_type *mtype,
> -                                       struct mdev_type_attribute
> *attr,
> -                                       char *buf)
> +static unsigned int mtty_get_available(struct mdev_type *mtype)
>  {
>         struct mtty_type *type = container_of(mtype, struct
> mtty_type, type);
>  
> -       return sprintf(buf, "%d\n", atomic_read(&mdev_avail_ports) /
> -                       type->nr_ports);
> +       return atomic_read(&mdev_avail_ports) / type->nr_ports;
>  }
>  
> -static MDEV_TYPE_ATTR_RO(available_instances);
> -
> -static const struct attribute *mdev_types_attrs[] = {
> -       &mdev_type_attr_available_instances.attr,
> -       NULL,
> -};
> -
>  static const struct vfio_device_ops mtty_dev_ops = {
>         .name = "vfio-mtty",
>         .init = mtty_init_dev,
> @@ -1292,7 +1282,7 @@ static struct mdev_driver mtty_driver = {
>         },
>         .probe = mtty_probe,
>         .remove = mtty_remove,
> -       .types_attrs = mdev_types_attrs,
> +       .get_available = mtty_get_available,
>  };
>  
>  static void mtty_device_release(struct device *dev)