Merge tag 'drm-intel-gt-next-2022-03-03' of git://anongit.freedesktop.org/drm/drm-intel into drm-next

Cross-subsystem Changes:

- drm-next backmerge for buddy allocator changes

Driver Changes:

- Skip i915_perf init for DG2 as it is not yet enabled (Ram)
- Add missing workarounds for DG2 (Clint)
- Add 64K page/align support for platforms like DG2 that require it (Matt A, Ram, Bob)
- Add accelerated migration support for DG2 (Matt A)
- Add flat CCS support for XeHP SDV (Abdiel, Ram)
- Add Compute Command Streamer (CCS) engine support for XeHP SDV (Michel,
  Daniele, Aravind, Matt R)
- Don't support parallel submission on compute / render (Matt B, Matt R)

- Disable i915 build on PREEMPT_RT until RT behaviour fixed (Sebastian)
- Remove RPS interrupt support for TGL+ (Jose)
- Fix S/R with PM_EARLY for non-GTT mappable objects on DG2 (Matt, Lucas)
- Skip stolen memory init if it is fully reserved (Jose)
- Use iosys_map for GuC data structures that may be in LMEM BAR or SMEM (Lucas)
- Do not complain about stale GuC reset notifications for banned contexts (John)

- Move context descriptor fields to intel_lrc.h
- Start adding support for small BAR (Matt A)
- Clarify vma lifetime (Thomas)
- Simplify subplatform detection on TGL (Jose)
- Correct the param count for unset GuC SLPC param (Vinay, Umesh)
- Read RP_STATE_CAP correctly on Gen12 with GuC SLPC (Vinay)
- Initialize GuC submission locks and queues early (Daniele)
- Fix GuC flag query helper function to not modify state (John)

- Drop fake lmem support now we have real hardware available (Lucas)
- Move misplaced W/A to their correct locations (Srinivasan)
- Use get_reset_domain() helper (Tejas)
- Move context descriptor fields to intel_lrc.h (Matt R)
- Selftest improvements (Matt A)

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YiBzY1dM7bKwMQ3H@jlahtine-mobl.ger.corp.intel.com

1 files changed, 40 insertions, 5 deletions

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 914ebd9290e5..05c3642aaece 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1118,10 +1118,16 @@ struct drm_i915_gem_exec_object2 {
 	/**
 	 * When the EXEC_OBJECT_PINNED flag is specified this is populated by
 	 * the user with the GTT offset at which this object will be pinned.
+	 *
 	 * When the I915_EXEC_NO_RELOC flag is specified this must contain the
 	 * presumed_offset of the object.
+	 *
 	 * During execbuffer2 the kernel populates it with the value of the
 	 * current GTT offset of the object, for future presumed_offset writes.
+	 *
+	 * See struct drm_i915_gem_create_ext for the rules when dealing with
+	 * alignment restrictions with I915_MEMORY_CLASS_DEVICE, on devices with
+	 * minimum page sizes, like DG2.
 	 */
 	__u64 offset;
 
@@ -3144,11 +3150,40 @@ struct drm_i915_gem_create_ext {
 	 *
 	 * 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.
+	 *
+	 * DG2 64K min page size implications:
+	 *
+	 * On discrete platforms, starting from DG2, we have to contend with GTT
+	 * page size restrictions when dealing with I915_MEMORY_CLASS_DEVICE
+	 * objects.  Specifically the hardware only supports 64K or larger GTT
+	 * page sizes for such memory. The kernel will already ensure that all
+	 * I915_MEMORY_CLASS_DEVICE memory is allocated using 64K or larger page
+	 * sizes underneath.
+	 *
+	 * Note that the returned size here will always reflect any required
+	 * rounding up done by the kernel, i.e 4K will now become 64K on devices
+	 * such as DG2.
+	 *
+	 * Special DG2 GTT address alignment requirement:
+	 *
+	 * The GTT alignment will also need to be at least 2M for such objects.
+	 *
+	 * Note that due to how the hardware implements 64K GTT page support, we
+	 * have some further complications:
+	 *
+	 *   1) The entire PDE (which covers a 2MB virtual address range), must
+	 *   contain only 64K PTEs, i.e mixing 4K and 64K PTEs in the same
+	 *   PDE is forbidden by the hardware.
+	 *
+	 *   2) We still need to support 4K PTEs for I915_MEMORY_CLASS_SYSTEM
+	 *   objects.
+	 *
+	 * To keep things simple for userland, we mandate that any GTT mappings
+	 * must be aligned to and rounded up to 2MB. The kernel will internally
+	 * pad them out to the next 2MB boundary. As this only wastes virtual
+	 * address space and avoids userland having to copy any needlessly
+	 * complicated PDE sharing scheme (coloring) and only affects DG2, this
+	 * is deemed to be a good compromise.
 	 */
 	__u64 size;
 	/**