drm/i915: Only track real ppgtt for a context

There's a bit a confusion since we track the global gtt,
the aliasing and real ppgtt in the ctx->vm pointer. And not
all callers really bother to check for the different cases and just
presume that it points to a real ppgtt.

Now looking closely we don't actually need ->vm to always point at an
address space - the only place that cares actually has fixup code
already to decide whether to look at the per-proces or the global
address space.

So switch to just tracking the ppgtt directly and ditch all the
extraneous code.

v2: Fixup the ppgtt debugfs file to not oops on a NULL ctx->ppgtt.
Also drop the early exit - without aliasing ppgtt we want to dump all
the ppgtts of the contexts if we have full ppgtt.

v3: Actually git add the compile fix.

Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Cc: "Thierry, Michel" <michel.thierry@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
OTC-Jira: VIZ-3724
[danvet: Resolve conflicts with execlist patches while applying.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1821,7 +1821,13 @@ static int per_file_ctx(int id, void *ptr, void *data)
 {
 	struct intel_context *ctx = ptr;
 	struct seq_file *m = data;
-	struct i915_hw_ppgtt *ppgtt = ctx_to_ppgtt(ctx);
+	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
+
+	if (!ppgtt) {
+		seq_printf(m, "  no ppgtt for context %d\n",
+			   ctx->user_handle);
+		return 0;
+	}
 
 	if (i915_gem_context_is_default(ctx))
 		seq_puts(m, "  default context:\n");
@@ -1881,8 +1887,7 @@ static void gen6_ppgtt_info(struct seq_file *m, struct drm_device *dev)
 		seq_printf(m, "pd gtt offset: 0x%08x\n", ppgtt->pd_offset);
 
 		ppgtt->debug_dump(ppgtt, m);
-	} else
-		return;
+	}
 
 	list_for_each_entry_reverse(file, &dev->filelist, lhead) {
 		struct drm_i915_file_private *file_priv = file->driver_priv;

drivers/gpu/drm/i915/i915_drv.h

@@ -624,7 +624,7 @@ struct intel_context {
 	uint8_t remap_slice;
 	struct drm_i915_file_private *file_priv;
 	struct i915_ctx_hang_stats hang_stats;
-	struct i915_address_space *vm;
+	struct i915_hw_ppgtt *ppgtt;
 
 	/* Legacy ring buffer submission */
 	struct {
@@ -2556,7 +2556,6 @@ i915_gem_object_ggtt_unbind(struct drm_i915_gem_object *obj)
 void i915_gem_object_ggtt_unpin(struct drm_i915_gem_object *obj);
 
 /* i915_gem_context.c */
-#define ctx_to_ppgtt(ctx) container_of((ctx)->vm, struct i915_hw_ppgtt, base)
 int __must_check i915_gem_context_init(struct drm_device *dev);
 void i915_gem_context_fini(struct drm_device *dev);
 void i915_gem_context_reset(struct drm_device *dev);

drivers/gpu/drm/i915/i915_gem_context.c

@@ -136,18 +136,12 @@ void i915_gem_context_free(struct kref *ctx_ref)
 {
 	struct intel_context *ctx = container_of(ctx_ref,
 						 typeof(*ctx), ref);
-	struct i915_hw_ppgtt *ppgtt = NULL;
 
-	if (i915.enable_execlists) {
-		ppgtt = ctx_to_ppgtt(ctx);
+	if (i915.enable_execlists)
 		intel_lr_context_free(ctx);
-	} else if (ctx->legacy_hw_ctx.rcs_state) {
-		/* We refcount even the aliasing PPGTT to keep the code symmetric */
-		if (USES_PPGTT(ctx->legacy_hw_ctx.rcs_state->base.dev))
-			ppgtt = ctx_to_ppgtt(ctx);
-	}
 
-	i915_ppgtt_put(ppgtt);
+	i915_ppgtt_put(ctx->ppgtt);
+
 	if (ctx->legacy_hw_ctx.rcs_state)
 		drm_gem_object_unreference(&ctx->legacy_hw_ctx.rcs_state->base);
 	list_del(&ctx->link);
@@ -243,7 +237,6 @@ i915_gem_create_context(struct drm_device *dev,
 			bool create_vm)
 {
 	const bool is_global_default_ctx = file_priv == NULL;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_context *ctx;
 	int ret = 0;
 
@@ -277,15 +270,10 @@ i915_gem_create_context(struct drm_device *dev,
 					 PTR_ERR(ppgtt));
 			ret = PTR_ERR(ppgtt);
 			goto err_unpin;
-		} else
-			ctx->vm = &ppgtt->base;
-	} else if (USES_PPGTT(dev)) {
-		/* For platforms which only have aliasing PPGTT, we fake the
-		 * address space and refcounting. */
-		ctx->vm = &dev_priv->mm.aliasing_ppgtt->base;
-		i915_ppgtt_get(dev_priv->mm.aliasing_ppgtt);
-	} else
-		ctx->vm = &dev_priv->gtt.base;
+		}
+
+		ctx->ppgtt = ppgtt;
+	}
 
 	return ctx;
 
@@ -543,7 +531,6 @@ static int do_switch(struct intel_engine_cs *ring,
 {
 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
 	struct intel_context *from = ring->last_context;
-	struct i915_hw_ppgtt *ppgtt = ctx_to_ppgtt(to);
 	u32 hw_flags = 0;
 	bool uninitialized = false;
 	int ret, i;
@@ -571,8 +558,8 @@ static int do_switch(struct intel_engine_cs *ring,
 	 */
 	from = ring->last_context;
 
-	if (USES_FULL_PPGTT(ring->dev)) {
-		ret = ppgtt->switch_mm(ppgtt, ring, false);
+	if (to->ppgtt) {
+		ret = to->ppgtt->switch_mm(to->ppgtt, ring, false);
 		if (ret)
 			goto unpin_out;
 	}

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -1315,8 +1315,9 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 
 	i915_gem_context_reference(ctx);
 
-	vm = ctx->vm;
-	if (!USES_FULL_PPGTT(dev))
+	if (ctx->ppgtt)
+		vm = &ctx->ppgtt->base;
+	else
 		vm = &dev_priv->gtt.base;
 
 	eb = eb_create(args);

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -967,6 +967,12 @@ static void i915_gem_record_rings(struct drm_device *dev,
 
 		request = i915_gem_find_active_request(ring);
 		if (request) {
+			struct i915_address_space *vm;
+
+			vm = request->ctx && request->ctx->ppgtt ?
+				&request->ctx->ppgtt->base :
+				&dev_priv->gtt.base;
+
 			/* We need to copy these to an anonymous buffer
 			 * as the simplest method to avoid being overwritten
 			 * by userspace.
@@ -974,9 +980,7 @@ static void i915_gem_record_rings(struct drm_device *dev,
 			error->ring[i].batchbuffer =
 				i915_error_object_create(dev_priv,
 							 request->batch_obj,
-							 request->ctx ?
-							 request->ctx->vm :
-							 &dev_priv->gtt.base);
+							 vm);
 
 			if (HAS_BROKEN_CS_TLB(dev_priv->dev) &&
 			    ring->scratch.obj)

drivers/gpu/drm/i915/intel_lrc.c

@@ -904,7 +904,7 @@ populate_lr_context(struct intel_context *ctx, struct drm_i915_gem_object *ctx_o
 		    struct intel_engine_cs *ring, struct intel_ringbuffer *ringbuf)
 {
 	struct drm_i915_gem_object *ring_obj = ringbuf->obj;
-	struct i915_hw_ppgtt *ppgtt = ctx_to_ppgtt(ctx);
+	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
 	struct page *page;
 	uint32_t *reg_state;
 	int ret;