Re: [Intel-gfx] [PATCH v4 17/17] drm/i915/vm_bind: Add uapi for user to enable vm_bind_mode

[Matthew Auld <matthew.auld@intel.com>]

On 18/10/2022 08:16, Niranjana Vishwanathapura wrote:
> Add getparam support for VM_BIND capability version.
> Add VM creation time flag to enable vm_bind_mode for the VM.
> 
> v2: update kernel-doc
> v3: create vm->root_obj only upon I915_VM_CREATE_FLAGS_USE_VM_BIND
> v4: replace vm->vm_bind_mode check with i915_gem_vm_is_vm_bind_mode()
> 
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
> Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_context.c | 25 +++++++++++++++++++--
>   drivers/gpu/drm/i915/gem/i915_gem_context.h |  3 +--
>   drivers/gpu/drm/i915/gt/intel_gtt.c         |  2 ++
>   drivers/gpu/drm/i915/i915_drv.h             |  2 ++
>   drivers/gpu/drm/i915/i915_getparam.c        |  3 +++
>   include/uapi/drm/i915_drm.h                 | 22 +++++++++++++++++-
>   6 files changed, 52 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index 76c6419b7ae0..0376adbbeecc 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -1803,9 +1803,13 @@ int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
>   	if (!HAS_FULL_PPGTT(i915))
>   		return -ENODEV;
>   
> -	if (args->flags)
> +	if (args->flags & I915_VM_CREATE_FLAGS_UNKNOWN)
>   		return -EINVAL;
>   
> +	if ((args->flags & I915_VM_CREATE_FLAGS_USE_VM_BIND) &&
> +	    !HAS_VM_BIND(i915))
> +		return -EOPNOTSUPP;
> +
>   	ppgtt = i915_ppgtt_create(to_gt(i915), 0);
>   	if (IS_ERR(ppgtt))
>   		return PTR_ERR(ppgtt);
> @@ -1818,15 +1822,32 @@ int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
>   			goto err_put;
>   	}
>   
> +	if (args->flags & I915_VM_CREATE_FLAGS_USE_VM_BIND) {
> +		struct drm_i915_gem_object *obj;
> +
> +		obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
> +		if (IS_ERR(obj)) {
> +			err = PTR_ERR(obj);
> +			goto err_put;
> +		}
> +
> +		ppgtt->vm.root_obj = obj;
> +	}
> +
>   	err = xa_alloc(&file_priv->vm_xa, &id, &ppgtt->vm,
>   		       xa_limit_32b, GFP_KERNEL);
>   	if (err)
> -		goto err_put;
> +		goto err_root_obj_put;
>   
>   	GEM_BUG_ON(id == 0); /* reserved for invalid/unassigned ppgtt */
>   	args->vm_id = id;
>   	return 0;
>   
> +err_root_obj_put:
> +	if (ppgtt->vm.root_obj) {
> +		i915_gem_object_put(ppgtt->vm.root_obj);
> +		ppgtt->vm.root_obj = NULL;
> +	}
>   err_put:
>   	i915_vm_put(&ppgtt->vm);
>   	return err;
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h
> index e8b41aa8f8c4..b53aef2853cb 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h
> @@ -150,8 +150,7 @@ int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, void *data,
>    */
>   static inline bool i915_gem_vm_is_vm_bind_mode(struct i915_address_space *vm)
>   {
> -	/* No support to enable vm_bind mode yet */
> -	return false;
> +	return !!vm->root_obj;
>   }
>   
>   struct i915_address_space *
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
> index 50648ab9214a..ae66fdd4bce9 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
> @@ -178,6 +178,8 @@ int i915_vm_lock_objects(struct i915_address_space *vm,
>   void i915_address_space_fini(struct i915_address_space *vm)
>   {
>   	drm_mm_takedown(&vm->mm);
> +	if (vm->root_obj)
> +		i915_gem_object_put(vm->root_obj);
>   	GEM_BUG_ON(!RB_EMPTY_ROOT(&vm->va.rb_root));
>   	mutex_destroy(&vm->vm_bind_lock);
>   }
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 7c64f8a17493..f4e7f3d4aff9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -972,6 +972,8 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
>   #define HAS_BAR2_SMEM_STOLEN(i915) (!HAS_LMEM(i915) && \
>   				    GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70))
>   
> +#define HAS_VM_BIND(i915) (GRAPHICS_VER(i915) >= 12)
> +
>   /* intel_device_info.c */
>   static inline struct intel_device_info *
>   mkwrite_device_info(struct drm_i915_private *dev_priv)
> diff --git a/drivers/gpu/drm/i915/i915_getparam.c b/drivers/gpu/drm/i915/i915_getparam.c
> index 342c8ca6414e..f45b3c684bcf 100644
> --- a/drivers/gpu/drm/i915/i915_getparam.c
> +++ b/drivers/gpu/drm/i915/i915_getparam.c
> @@ -175,6 +175,9 @@ int i915_getparam_ioctl(struct drm_device *dev, void *data,
>   	case I915_PARAM_PERF_REVISION:
>   		value = i915_perf_ioctl_version();
>   		break;
> +	case I915_PARAM_VM_BIND_VERSION:
> +		value = HAS_VM_BIND(i915);
> +		break;
>   	default:
>   		DRM_DEBUG("Unknown parameter %d\n", param->param);
>   		return -EINVAL;
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index fe7ee8f19c83..c2dce8633005 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -771,6 +771,22 @@ typedef struct drm_i915_irq_wait {
>   /* Query if the kernel supports the I915_USERPTR_PROBE flag. */
>   #define I915_PARAM_HAS_USERPTR_PROBE 56
>   
> +/*
> + * VM_BIND feature version supported.
> + *
> + * The following versions of VM_BIND have been defined:
> + *
> + * 0: No VM_BIND support.
> + *
> + * 1: In VM_UNBIND calls, the UMD must specify the exact mappings created
> + *    previously with VM_BIND, the ioctl will not support unbinding multiple
> + *    mappings or splitting them. Similarly, VM_BIND calls will not replace
> + *    any existing mappings.
> + *
> + * See struct drm_i915_gem_vm_bind and struct drm_i915_gem_vm_unbind.
> + */
> +#define I915_PARAM_VM_BIND_VERSION	57
> +
>   /* Must be kept compact -- no holes and well documented */
>   
>   /**
> @@ -2622,6 +2638,9 @@ struct drm_i915_gem_context_destroy {
>    * on the same file. Extensions can be provided to configure exactly how the
>    * address space is setup upon creation.
>    *
> + * If I915_VM_CREATE_FLAGS_USE_VM_BIND flag is set, VM created will work in
> + * VM_BIND mode.
> + *
>    * The id of new VM (bound to the fd) for use with I915_CONTEXT_PARAM_VM is
>    * returned in the outparam @id.
>    *
> @@ -2638,7 +2657,8 @@ struct drm_i915_gem_vm_control {
>   	/** @extensions: Zero-terminated chain of extensions. */
>   	__u64 extensions;
>   
> -	/** @flags: reserved for future usage, currently MBZ */

This looks to remove the kernel-doc completely, instead of updating it.

> +#define I915_VM_CREATE_FLAGS_USE_VM_BIND	(1u << 0)
> +#define I915_VM_CREATE_FLAGS_UNKNOWN	(-(I915_VM_CREATE_FLAGS_USE_VM_BIND << 1))
>   	__u32 flags;
>   
>   	/** @vm_id: Id of the VM created or to be destroyed */