[PATCH 7/8] drm/i915: Explicitly mark Global GTT address spaces

[Tvrtko Ursulin <tursulin@ursulin.net>]

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

So far we have been relying on vm->file pointer being NULL to declare
something GGTT.

This has the unfortunate consequence that the default kernel context is
also declared GGTT and interferes with the following patch which wants to
instantiate VMA's and execute requests against the kernel context.

Change the is_ggtt test to use an explicit flag in struct address_space to
solve this issue.

Note that the bit used is free since there is an alignment hole in the
struct.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 2 ++
 drivers/gpu/drm/i915/i915_gem_gtt.h | 5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 4137af4bd8f5..64151ad2a02b 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3610,6 +3610,8 @@ int i915_ggtt_init_hw(struct drm_i915_private *dev_priv)
 	mutex_lock(&dev_priv->drm.struct_mutex);
 	i915_address_space_init(&ggtt->vm, dev_priv);
 
+	ggtt->vm.is_ggtt = true;
+
 	/* Only VLV supports read-only GGTT mappings */
 	ggtt->vm.has_read_only = IS_VALLEYVIEW(dev_priv);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index dd161c187a68..d8dd4d9280bd 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -331,6 +331,9 @@ struct i915_address_space {
 
 	struct pagestash free_pages;
 
+	/* Global GTT */
+	bool is_ggtt:1;
+
 	/* Some systems require uncached updates of the page directories */
 	bool pt_kmap_wc:1;
 
@@ -364,7 +367,7 @@ struct i915_address_space {
 	I915_SELFTEST_DECLARE(bool scrub_64K);
 };
 
-#define i915_is_ggtt(V) (!(V)->file)
+#define i915_is_ggtt(vm) ((vm)->is_ggtt)
 
 static inline bool
 i915_vm_is_48bit(const struct i915_address_space *vm)
-- 
2.17.1

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