intel: 48b ppgtt support (EXEC_OBJECT_SUPPORTS_48B_ADDRESS flag)

Gen8+ supports 48-bit virtual addresses, but some objects must always be
allocated inside the 32-bit address range.

In specific, any resource used with flat/heapless (0x00000000-0xfffff000)
General State Heap (GSH) or Instruction State Heap (ISH) must be in a
32-bit range, because the General State Offset and Instruction State Offset
are limited to 32-bits.

The i915 driver has been modified to provide a flag to set when the 4GB
limit is not necessary in a given bo (EXEC_OBJECT_SUPPORTS_48B_ADDRESS).
48-bit range will only be used when explicitly requested.

Callers to the existing drm_intel_bo_emit_reloc function should set the
use_48b_address_range flag beforehand, in order to use full ppgtt range.

v2: Make set/clear functions nops on pre-gen8 platforms, and use them
    internally in emit_reloc functions (Ben)
    s/48BADDRESS/48B_ADDRESS/ (Dave)
v3: Keep set/clear functions internal, no-one needs to use them directly.
v4: Don't set 48bit-support flag in emit reloc, check for ppgtt type
    before enabling set/clear function, print full offsets in debug
    statements, using port of lower_32_bits and upper_32_bits from linux
    kernel (Michał)

References: http://lists.freedesktop.org/archives/intel-gfx/2015-July/072612.html
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Kristian Høgsberg Kristensen <kristian.h.kristensen@intel.com>
Signed-off-by: Kristian Høgsberg Kristensen <kristian.h.kristensen@intel.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/intel/intel_bufmgr_priv.h b/intel/intel_bufmgr_priv.h
index 59ebd186..5c17ffbe 100644
--- a/intel/intel_bufmgr_priv.h
+++ b/intel/intel_bufmgr_priv.h
@@ -152,6 +152,20 @@ struct _drm_intel_bufmgr {
 	void (*destroy) (drm_intel_bufmgr *bufmgr);
 
 	/**
+	 * Indicate if the buffer can be placed anywhere in the full ppgtt
+	 * address range (2^48).
+	 *
+	 * Any resource used with flat/heapless (0x00000000-0xfffff000)
+	 * General State Heap (GSH) or Intructions State Heap (ISH) must
+	 * be in a 32-bit range. 48-bit range will only be used when explicitly
+	 * requested.
+	 *
+	 * \param bo Buffer to set the use_48b_address_range flag.
+	 * \param enable The flag value.
+	 */
+	void (*bo_use_48b_address_range) (drm_intel_bo *bo, uint32_t enable);
+
+	/**
 	 * Add relocation entry in reloc_buf, which will be updated with the
 	 * target buffer's real offset on on command submission.
 	 *