[Intel-gfx] [PATCH v2 1/2] drm/i915: Match code to comment and enforce ppgtt for execlists

[Chris Wilson]

Our execlist dispatch code requires a ppGTT so make sure we enforce that
option in intel_sanitize_enable_ppgtt(). The comment already tries to
explain that execlists requires ppgtt, but was written when gen8 may
have also taken the legacy path; so rewrite the code to match the
comment by using HAS_EXECLISTS() feature instead of the gen.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 4 ++--
 drivers/gpu/drm/i915/intel_lrc.c    | 5 +++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 56c7f8637311..f6c7ab413081 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -152,10 +152,10 @@ int intel_sanitize_enable_ppgtt(struct drm_i915_private *dev_priv,
 	}
 
 	/*
-	 * We don't allow disabling PPGTT for gen9+ as it's a requirement for
+	 * We don't allow disabling PPGTT for gen8+ as it's a requirement for
 	 * execlists, the sole mechanism available to submit work.
 	 */
-	if (enable_ppgtt == 0 && INTEL_GEN(dev_priv) < 9)
+	if (enable_ppgtt == 0 && !HAS_EXECLISTS(dev_priv))
 		return 0;
 
 	if (enable_ppgtt == 1)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 43957bb37a42..400f5c83d402 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -429,7 +429,7 @@ static u64 execlists_update_context(struct i915_request *rq)
 	 * PML4 is allocated during ppgtt init, so this is not needed
 	 * in 48-bit mode.
 	 */
-	if (ppgtt && !i915_vm_is_48bit(&ppgtt->vm))
+	if (!i915_vm_is_48bit(&ppgtt->vm))
 		execlists_update_context_pdps(ppgtt, reg_state);
 
 	return ce->lrc_desc;
@@ -1375,6 +1375,7 @@ execlists_context_pin(struct intel_engine_cs *engine,
 	struct intel_context *ce = to_intel_context(ctx, engine);
 
 	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
+	GEM_BUG_ON(!(ctx->ppgtt ?: ctx->i915->mm.aliasing_ppgtt));
 
 	if (likely(ce->pin_count++))
 		return ce;
@@ -2704,7 +2705,7 @@ static void execlists_init_reg_state(u32 *regs,
 	CTX_REG(regs, CTX_PDP0_UDW, GEN8_RING_PDP_UDW(engine, 0), 0);
 	CTX_REG(regs, CTX_PDP0_LDW, GEN8_RING_PDP_LDW(engine, 0), 0);
 
-	if (ppgtt && i915_vm_is_48bit(&ppgtt->vm)) {
+	if (i915_vm_is_48bit(&ppgtt->vm)) {
 		/* 64b PPGTT (48bit canonical)
 		 * PDP0_DESCRIPTOR contains the base address to PML4 and
 		 * other PDP Descriptors are ignored.
-- 
2.19.0