Add an entry for the new uapi needed for small BAR on DG2+.
v2:
- Some spelling fixes and other small tweaks. (Akeem & Thomas)
- Rework error capture interactions, including no longer needing
NEEDS_CPU_ACCESS for objects marked for capture. (Thomas)
- Add probed_cpu_visible_size. (Lionel)
v3:
- Drop the vma query for now.
- Add unallocated_cpu_visible_size as part of the region query.
- Improve the docs some more, including documenting the expected
behaviour on older kernels, since this came up in some offline
discussion.
Signed-off-by: Matthew Auld
Cc: Thomas Hellström
Cc: Lionel Landwerlin
Cc: Tvrtko Ursulin
Cc: Jon Bloomfield
Cc: Daniel Vetter
Cc: Jon Bloomfield
Cc: Jordan Justen
Cc: Kenneth Graunke
Cc: Akeem G Abodunrin
Cc: mesa-dev@lists.freedesktop.org
---
Documentation/gpu/rfc/i915_small_bar.h | 164 +++
Documentation/gpu/rfc/i915_small_bar.rst | 47 +++
Documentation/gpu/rfc/index.rst | 4 +
3 files changed, 215 insertions(+)
create mode 100644 Documentation/gpu/rfc/i915_small_bar.h
create mode 100644 Documentation/gpu/rfc/i915_small_bar.rst
diff --git a/Documentation/gpu/rfc/i915_small_bar.h
b/Documentation/gpu/rfc/i915_small_bar.h
new file mode 100644
index ..4079d287750b
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_small_bar.h
@@ -0,0 +1,164 @@
+/**
+ * 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 (-1 = unknown) */
+ __u64 probed_size;
+
+ /**
+* @unallocated_size: Estimate of memory remaining (-1 = unknown)
+*
+* Note this is only currently tracked for I915_MEMORY_CLASS_DEVICE
+* regions, and also requires CAP_PERFMON or CAP_SYS_ADMIN to get
+* reliable accounting. Without this(or if this an older kernel) the
+* value here will always match 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. (-1 = unknown).
+*
+* 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 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 (-1 = unknown).
+*
+* Note this is only currently tracked for
+* I915_MEMORY_CLASS_DEVICE regions, and also requires
+* CAP_PERFMON or CAP_SYS_ADMIN to get reliable
+* accounting. Without this the value here will always
+* equal the @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
