[PATCH v2 17/32] drm/xe/uapi: Add madvise interface

[Souza, Jose]

On Mon, 2025-04-07 at 15:47 +0530, Himal Prasad Ghimiray wrote:
> This commit introduces a new madvise interface to support
> driver-specific ioctl operations. The madvise interface allows for more
> efficient memory management by providing hints to the driver about the
> expected memory usage and pte update policy for gpuvma.
> 
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
> ---
>  include/uapi/drm/xe_drm.h | 97 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 97 insertions(+)
> 
> diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
> index 9c08738c3b91..aaf515df3a83 100644
> --- a/include/uapi/drm/xe_drm.h
> +++ b/include/uapi/drm/xe_drm.h
> @@ -81,6 +81,7 @@ extern "C" {
>   *  - &DRM_IOCTL_XE_EXEC
>   *  - &DRM_IOCTL_XE_WAIT_USER_FENCE
>   *  - &DRM_IOCTL_XE_OBSERVATION
> + *  - &DRM_IOCTL_XE_MADVISE
>   */
>  
>  /*
> @@ -102,6 +103,7 @@ extern "C" {
>  #define DRM_XE_EXEC			0x09
>  #define DRM_XE_WAIT_USER_FENCE		0x0a
>  #define DRM_XE_OBSERVATION		0x0b
> +#define DRM_XE_MADVISE			0x0c
>  
>  /* Must be kept compact -- no holes */
>  
> @@ -117,6 +119,7 @@ extern "C" {
>  #define DRM_IOCTL_XE_EXEC			DRM_IOW(DRM_COMMAND_BASE + DRM_XE_EXEC, struct drm_xe_exec)
>  #define DRM_IOCTL_XE_WAIT_USER_FENCE		DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_WAIT_USER_FENCE, struct drm_xe_wait_user_fence)
>  #define DRM_IOCTL_XE_OBSERVATION		DRM_IOW(DRM_COMMAND_BASE + DRM_XE_OBSERVATION, struct drm_xe_observation_param)
> +#define DRM_IOCTL_XE_MADVISE			DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_MADVISE, struct drm_xe_madvise)
>  
>  /**
>   * DOC: Xe IOCTL Extensions
> @@ -1965,6 +1968,100 @@ struct drm_xe_query_eu_stall {
>  	__u64 sampling_rates[];
>  };
>  
> +struct drm_xe_madvise_ops {
> +	/** @start: start of the virtual address range */
> +	__u64 start;
> +
> +	/** @size: size of the virtual address range */
> +	__u64 range;
> +
> +#define DRM_XE_VMA_ATTR_PREFERRED_LOC	0
> +#define DRM_XE_VMA_ATTR_ATOMIC		1
> +#define DRM_XE_VMA_ATTR_PAT		2

In my opinion we should drop DRM_XE_VMA_ATTR_PAT as we can already change the PAT index by unbinding and binding the VM with the wanted PAT index.
Similar for DRM_XE_VMA_ATTR_ATOMIC and DRM_XE_VMA_ATTR_PREFERRED_LOC, we could have those properties in vm bind uAPI and if needed to change we could
unbind and bind the VMA with the updated attributes.

> +#define DRM_XE_VMA_ATTR_PURGEABLE_STATE	3

Mesa can make use of DRM_XE_VMA_ATTR_PURGEABLE_STATE but not the other ones, so you will need other UMDs to land those.

> +	/** @type: type of attribute */
> +	__u32 type;
> +
> +	/** @pad: MBZ */
> +	__u32 pad;
> +
> +	union {
> +		struct {
> +#define DRM_XE_VMA_ATOMIC_UNDEFINED	0
> +#define DRM_XE_VMA_ATOMIC_DEVICE	1
> +#define DRM_XE_VMA_ATOMIC_GLOBAL	2
> +#define DRM_XE_VMA_ATOMIC_CPU		3
> +		/** @val: value of atomic operation*/
> +			__u32 val;
> +
> +		/** @reserved: Reserved */
> +			__u32 reserved;
> +		} atomic;
> +
> +		struct {
> +#define DRM_XE_VMA_PURGEABLE_STATE_WILLNEED	0
> +#define DRM_XE_VMA_PURGEABLE_STATE_DONTNEED	1
> +#define DRM_XE_VMA_PURGEABLE_STATE_PURGED	2
> +		/** @val: value for DRM_XE_VMA_ATTR_PURGEABLE_STATE */
> +			__u32 val;
> +
> +		/** @reserved: Reserved */
> +			__u32 reserved;
> +		} purge_state_val;
> +
> +		struct {
> +			/** @pat_index */
> +			__u32 val;
> +
> +			/** @reserved: Reserved */
> +			__u32 reserved;
> +		} pat_index;
> +
> +		/** @preferred_mem_loc: preferred memory location */
> +		struct {
> +			__u32 devmem_fd;
> +
> +#define MIGRATE_ALL_PAGES 0
> +#define MIGRATE_ONLY_SYSTEM_PAGES 1
> +			__u32 migration_policy;
> +		} preferred_mem_loc;
> +	};
> +
> +	/** @reserved: Reserved */
> +	__u64 reserved[2];
> +};
> +
> +/**
> + * struct drm_xe_madvise - Input of &DRM_IOCTL_XE_MADVISE
> + *
> + * Set memory attributes to a virtual address range
> + */
> +struct drm_xe_madvise {
> +	/** @extensions: Pointer to the first extension struct, if any */
> +	__u64 extensions;
> +
> +	/** @vm_id: vm_id of the virtual range */
> +	__u32 vm_id;
> +
> +	/** @num_ops: number of madvises in ioctl */
> +	__u32 num_ops;
> +
> +	union {
> +		/** @ops: used if num_ops == 1 */
> +		struct drm_xe_madvise_ops ops;
> +
> +		/**
> +		 * @vector_of_ops: userptr to array of struct
> +		 * drm_xe_vm_madvise_op if num_ops > 1
> +		 */
> +		__u64 vector_of_ops;
> +	};
> +
> +	/** @reserved: Reserved */
> +	__u64 reserved[2];
> +
> +};
> +
>  #if defined(__cplusplus)
>  }
>  #endif