Re: [PATCH 16/16] drm/i915/vm_bind: Add uapi for user to enable vm_bind_mode

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

On 28/09/2022 07:19, Niranjana Vishwanathapura wrote:
> Add getparam support for VM_BIND capability version.
> Add VM creation time flag to enable vm_bind_mode for the VM.
> 
> 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 |  9 +++++++-
>   drivers/gpu/drm/i915/i915_drv.h             |  2 ++
>   drivers/gpu/drm/i915/i915_getparam.c        |  3 +++
>   include/uapi/drm/i915_drm.h                 | 24 ++++++++++++++++++++-
>   4 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index f4e648ec01ed..c20bd6e8aaf8 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -1808,9 +1808,13 @@ 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);
> @@ -1828,6 +1832,9 @@ int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
>   	if (err)
>   		goto err_put;
>   
> +	if (args->flags & I915_VM_CREATE_FLAGS_USE_VM_BIND)
> +		ppgtt->vm.vm_bind_mode = true;
> +
>   	GEM_BUG_ON(id == 0); /* reserved for invalid/unassigned ppgtt */
>   	args->vm_id = id;
>   	return 0;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 84a2f6b16f57..e77393d74c6f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -974,6 +974,8 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
>   
>   #define HAS_ONE_EU_PER_FUSE_BIT(i915)	(INTEL_INFO(i915)->has_one_eu_per_fuse_bit)
>   
> +#define HAS_VM_BIND(dev_priv) (GRAPHICS_VER(dev_priv) >= 12)

s/dev_priv/i915/

> +
>   /* 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 f3a5b198b3e7..9a033acc254b 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -755,6 +755,27 @@ 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.
> + *
> + * 2: The restrictions on unbinding partial or multiple mappings is
> + *    lifted, Similarly, binding will replace any mappings in the given range.

Should we just remove 2 for now? It looks like 1 is this series.

> + *
> + * See struct drm_i915_gem_vm_bind and struct drm_i915_gem_vm_unbind.
> + *
> + * vm_bind versions are backward compatible.
> + */
> +#define I915_PARAM_VM_BIND_VERSION	57
> +
>   /* Must be kept compact -- no holes and well documented */
>   
>   /**
> @@ -2622,7 +2643,8 @@ struct drm_i915_gem_vm_control {
>   	/** @extensions: Zero-terminated chain of extensions. */
>   	__u64 extensions;
>   
> -	/** @flags: reserved for future usage, currently MBZ */
> +#define I915_VM_CREATE_FLAGS_USE_VM_BIND	(1u << 0)

Some kernel-doc for that would be good, even if it's kind of obvious.

Acked-by: Matthew Auld <matthew.auld@intel.com>

> +#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 */