OSCL-LXR linux-6.0.1/​Documentation/​gpu/​rfc/​i915_small_bar.h	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /**
  * struct __drm_i915_memory_region_info - Describes one region as known to the
  * driver.
  *
  * Note this is using both struct drm_i915_query_item and struct drm_i915_query.
  * For this new query we are adding the new query id DRM_I915_QUERY_MEMORY_REGIONS
  * at &drm_i915_query_item.query_id.
  */
 struct __drm_i915_memory_region_info {
     /** @region: The class:instance pair encoding */
     struct drm_i915_gem_memory_class_instance region;
 
     /** @rsvd0: MBZ */
     __u32 rsvd0;
 
     /**
      * @probed_size: Memory probed by the driver
      *
      * Note that it should not be possible to ever encounter a zero value
      * here, also note that no current region type will ever return -1 here.
      * Although for future region types, this might be a possibility. The
      * same applies to the other size fields.
      */
     __u64 probed_size;
 
     /**
      * @unallocated_size: Estimate of memory remaining
      *
      * Requires CAP_PERFMON or CAP_SYS_ADMIN to get reliable accounting.
      * Without this (or if this is an older kernel) the value here will
      * always equal the @probed_size. Note this is only currently tracked
      * for I915_MEMORY_CLASS_DEVICE regions (for other types the value here
      * will always equal the @probed_size).
      */
     __u64 unallocated_size;
 
     union {
         /** @rsvd1: MBZ */
         __u64 rsvd1[8];
         struct {
             /**
              * @probed_cpu_visible_size: Memory probed by the driver
              * that is CPU accessible.
              *
              * This will be always be <= @probed_size, and the
              * remainder (if there is any) will not be CPU
              * accessible.
              *
              * On systems without small BAR, the @probed_size will
              * always equal the @probed_cpu_visible_size, since all
              * of it will be CPU accessible.
              *
              * Note this is only tracked for
              * I915_MEMORY_CLASS_DEVICE regions (for other types the
              * value here will always equal the @probed_size).
              *
              * Note that if the value returned here is zero, then
              * this must be an old kernel which lacks the relevant
              * small-bar uAPI support (including
              * I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS), but on
              * such systems we should never actually end up with a
              * small BAR configuration, assuming we are able to load
              * the kernel module. Hence it should be safe to treat
              * this the same as when @probed_cpu_visible_size ==
              * @probed_size.
              */
             __u64 probed_cpu_visible_size;
 
             /**
              * @unallocated_cpu_visible_size: Estimate of CPU
              * visible memory remaining
              *
              * Note this is only tracked for
              * I915_MEMORY_CLASS_DEVICE regions (for other types the
              * value here will always equal the
              * @probed_cpu_visible_size).
              *
              * Requires CAP_PERFMON or CAP_SYS_ADMIN to get reliable
              * accounting.  Without this the value here will always
              * equal the @probed_cpu_visible_size. Note this is only
              * currently tracked for I915_MEMORY_CLASS_DEVICE
              * regions (for other types the value here will also
              * always equal the @probed_cpu_visible_size).
              *
              * If this is an older kernel the value here will be
              * zero, see also @probed_cpu_visible_size.
              */
             __u64 unallocated_cpu_visible_size;
         };
     };
 };
 
 /**
  * struct __drm_i915_gem_create_ext - Existing gem_create behaviour, with added
  * extension support using struct i915_user_extension.
  *
  * Note that new buffer flags should be added here, at least for the stuff that
  * is immutable. Previously we would have two ioctls, one to create the object
  * with gem_create, and another to apply various parameters, however this
  * creates some ambiguity for the params which are considered immutable. Also in
  * general we're phasing out the various SET/GET ioctls.
  */
 struct __drm_i915_gem_create_ext {
     /**
      * @size: Requested size for the object.
      *
      * The (page-aligned) allocated size for the object will be returned.
      *
      * Note that for some devices we have might have further minimum
      * page-size restrictions (larger than 4K), like for device local-memory.
      * However in general the final size here should always reflect any
      * rounding up, if for example using the I915_GEM_CREATE_EXT_MEMORY_REGIONS
      * extension to place the object in device local-memory. The kernel will
      * always select the largest minimum page-size for the set of possible
      * placements as the value to use when rounding up the @size.
      */
     __u64 size;
 
     /**
      * @handle: Returned handle for the object.
      *
      * Object handles are nonzero.
      */
     __u32 handle;
 
     /**
      * @flags: Optional flags.
      *
      * Supported values:
      *
      * I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS - Signal to the kernel that
      * the object will need to be accessed via the CPU.
      *
      * Only valid when placing objects in I915_MEMORY_CLASS_DEVICE, and only
      * strictly required on configurations where some subset of the device
      * memory is directly visible/mappable through the CPU (which we also
      * call small BAR), like on some DG2+ systems. Note that this is quite
      * undesirable, but due to various factors like the client CPU, BIOS etc
      * it's something we can expect to see in the wild. See
      * &__drm_i915_memory_region_info.probed_cpu_visible_size for how to
      * determine if this system applies.
      *
      * Note that one of the placements MUST be I915_MEMORY_CLASS_SYSTEM, to
      * ensure the kernel can always spill the allocation to system memory,
      * if the object can't be allocated in the mappable part of
      * I915_MEMORY_CLASS_DEVICE.
      *
      * Also note that since the kernel only supports flat-CCS on objects
      * that can *only* be placed in I915_MEMORY_CLASS_DEVICE, we therefore
      * don't support I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS together with
      * flat-CCS.
      *
      * Without this hint, the kernel will assume that non-mappable
      * I915_MEMORY_CLASS_DEVICE is preferred for this object. Note that the
      * kernel can still migrate the object to the mappable part, as a last
      * resort, if userspace ever CPU faults this object, but this might be
      * expensive, and so ideally should be avoided.
      *
      * On older kernels which lack the relevant small-bar uAPI support (see
      * also &__drm_i915_memory_region_info.probed_cpu_visible_size),
      * usage of the flag will result in an error, but it should NEVER be
      * possible to end up with a small BAR configuration, assuming we can
      * also successfully load the i915 kernel module. In such cases the
      * entire I915_MEMORY_CLASS_DEVICE region will be CPU accessible, and as
      * such there are zero restrictions on where the object can be placed.
      */
 #define I915_GEM_CREATE_EXT_FLAG_NEEDS_CPU_ACCESS (1 << 0)
     __u32 flags;
 
     /**
      * @extensions: The chain of extensions to apply to this object.
      *
      * This will be useful in the future when we need to support several
      * different extensions, and we need to apply more than one when
      * creating the object. See struct i915_user_extension.
      *
      * If we don't supply any extensions then we get the same old gem_create
      * behaviour.
      *
      * For I915_GEM_CREATE_EXT_MEMORY_REGIONS usage see
      * struct drm_i915_gem_create_ext_memory_regions.
      *
      * For I915_GEM_CREATE_EXT_PROTECTED_CONTENT usage see
      * struct drm_i915_gem_create_ext_protected_content.
      */
 #define I915_GEM_CREATE_EXT_MEMORY_REGIONS 0
 #define I915_GEM_CREATE_EXT_PROTECTED_CONTENT 1
     __u64 extensions;
 };

This page was automatically generated by the 2.1.0 LXR engine. The LXR team