[Intel-gfx] [PATCH 09/40] drm/i915: Restore control over ppgtt for context creation ABI

[Tvrtko Ursulin]

On 08/05/2019 09:06, Chris Wilson wrote:
> Having hid the partially exposed new ABI from the PR, put it back again
> for completion of context recovery. A significant part of context
> recovery is the ability to reuse as much of the old context as is
> feasible (to avoid expensive reconstruction). The biggest chunk kept
> hidden at the moment is fine-control over the ctx->ppgtt (the GPU page
> tables and associated translation tables and kernel maps), so make
> control over the ctx->ppgtt explicit.
> 
> This allows userspace to create and share virtual memory address spaces
> (within the limits of a single fd) between contexts they own, along with
> the ability to query the contexts for the vm state.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/i915_drv.c         |  2 ++
>   drivers/gpu/drm/i915/i915_gem_context.c |  5 -----
>   include/uapi/drm/i915_drm.h             | 15 +++++++++++++++
>   3 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 2c7a4318d13c..5061cb32856b 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -3164,6 +3164,8 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
>   	DRM_IOCTL_DEF_DRV(I915_PERF_ADD_CONFIG, i915_perf_add_config_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
>   	DRM_IOCTL_DEF_DRV(I915_PERF_REMOVE_CONFIG, i915_perf_remove_config_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
>   	DRM_IOCTL_DEF_DRV(I915_QUERY, i915_query_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
> +	DRM_IOCTL_DEF_DRV(I915_GEM_VM_CREATE, i915_gem_vm_create_ioctl, DRM_RENDER_ALLOW),
> +	DRM_IOCTL_DEF_DRV(I915_GEM_VM_DESTROY, i915_gem_vm_destroy_ioctl, DRM_RENDER_ALLOW),
>   };
>   
>   static struct drm_driver driver = {
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index 65cefc520e79..413c4529191d 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -98,7 +98,6 @@
>   #include "i915_user_extensions.h"
>   
>   #define I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE (1 << 1)
> -#define I915_CONTEXT_PARAM_VM 0x9
>   
>   #define ALL_L3_SLICES(dev) (1 << NUM_L3_SLICES(dev)) - 1
>   
> @@ -966,8 +965,6 @@ static int get_ppgtt(struct drm_i915_file_private *file_priv,
>   	struct i915_hw_ppgtt *ppgtt;
>   	int ret;
>   
> -	return -EINVAL; /* nothing to see here; please move along */
> -
>   	if (!ctx->ppgtt)
>   		return -ENODEV;
>   
> @@ -1066,8 +1063,6 @@ static int set_ppgtt(struct drm_i915_file_private *file_priv,
>   	struct i915_hw_ppgtt *ppgtt, *old;
>   	int err;
>   
> -	return -EINVAL; /* nothing to see here; please move along */
> -
>   	if (args->size)
>   		return -EINVAL;
>   
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 3a73f5316766..d6ad4a15b2b9 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -355,6 +355,8 @@ typedef struct _drm_i915_sarea {
>   #define DRM_I915_PERF_ADD_CONFIG	0x37
>   #define DRM_I915_PERF_REMOVE_CONFIG	0x38
>   #define DRM_I915_QUERY			0x39
> +#define DRM_I915_GEM_VM_CREATE		0x3a
> +#define DRM_I915_GEM_VM_DESTROY		0x3b
>   /* Must be kept compact -- no holes */
>   
>   #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
> @@ -415,6 +417,8 @@ typedef struct _drm_i915_sarea {
>   #define DRM_IOCTL_I915_PERF_ADD_CONFIG	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_ADD_CONFIG, struct drm_i915_perf_oa_config)
>   #define DRM_IOCTL_I915_PERF_REMOVE_CONFIG	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_REMOVE_CONFIG, __u64)
>   #define DRM_IOCTL_I915_QUERY			DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_QUERY, struct drm_i915_query)
> +#define DRM_IOCTL_I915_GEM_VM_CREATE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_CREATE, struct drm_i915_gem_vm_control)
> +#define DRM_IOCTL_I915_GEM_VM_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)
>   
>   /* Allow drivers to submit batchbuffers directly to hardware, relying
>    * on the security mechanisms provided by hardware.
> @@ -1507,6 +1511,17 @@ struct drm_i915_gem_context_param {
>    * On creation, all new contexts are marked as recoverable.
>    */
>   #define I915_CONTEXT_PARAM_RECOVERABLE	0x8
> +
> +	/*
> +	 * The id of the associated virtual memory address space (ppGTT) of
> +	 * this context. Can be retrieved and passed to another context
> +	 * (on the same fd) for both to use the same ppGTT and so share
> +	 * address layouts, and avoid reloading the page tables on context
> +	 * switches between themselves.
> +	 *
> +	 * See DRM_I915_GEM_VM_CREATE and DRM_I915_GEM_VM_DESTROY.
> +	 */
> +#define I915_CONTEXT_PARAM_VM		0x9
>   /* Must be kept compact -- no holes and well documented */
>   
>   	__u64 value;
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko