drm/i915/selftests: ditch the kernel context

There's really no good reason to be using the kernel context for the
huge-page livetests. Also with the introduction of commit bef27bdb6cfb
("drm/i915: Assert we do not try to expand VMA for hugepage inside GGTT")
we start hitting the bug on in the selftests, since the kernel context
will always return true for i915_vma_is_ggtt(), so now seems like the
opportune time to instead create our own context.

Fixes: 4049866f0913 ("drm/i915/selftests: huge page tests")
Fixes: bef27bdb6cfb ("drm/i915: Assert we do not try to expand VMA for hugepage inside GGTT")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171010133030.12112-1-matthew.auld@intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/selftests/huge_pages.c

@@ -1047,10 +1047,10 @@ static int cpu_check(struct drm_i915_gem_object *obj, u32 dword, u32 val)
 	return err;
 }
 
-static int igt_write_huge(struct drm_i915_gem_object *obj)
+static int igt_write_huge(struct i915_gem_context *ctx,
+			  struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
-	struct i915_gem_context *ctx = i915->kernel_context;
 	struct i915_address_space *vm = ctx->ppgtt ? &ctx->ppgtt->base : &i915->ggtt.base;
 	struct intel_engine_cs *engine;
 	struct i915_vma *vma;
@@ -1149,7 +1149,8 @@ out_vma_close:
 
 static int igt_ppgtt_exhaust_huge(void *arg)
 {
-	struct drm_i915_private *i915 = arg;
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *i915 = ctx->i915;
 	unsigned long supported = INTEL_INFO(i915)->page_sizes;
 	static unsigned int pages[ARRAY_SIZE(page_sizes)];
 	struct drm_i915_gem_object *obj;
@@ -1220,7 +1221,7 @@ static int igt_ppgtt_exhaust_huge(void *arg)
 			/* Force the page-size for the gtt insertion */
 			obj->mm.page_sizes.sg = page_sizes;
 
-			err = igt_write_huge(obj);
+			err = igt_write_huge(ctx, obj);
 			if (err) {
 				pr_err("exhaust write-huge failed with size=%u\n",
 				       size);
@@ -1245,7 +1246,8 @@ out_device:
 
 static int igt_ppgtt_internal_huge(void *arg)
 {
-	struct drm_i915_private *i915 = arg;
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *i915 = ctx->i915;
 	struct drm_i915_gem_object *obj;
 	static const unsigned int sizes[] = {
 		SZ_64K,
@@ -1280,7 +1282,7 @@ static int igt_ppgtt_internal_huge(void *arg)
 			goto out_unpin;
 		}
 
-		err = igt_write_huge(obj);
+		err = igt_write_huge(ctx, obj);
 		if (err) {
 			pr_err("internal write-huge failed with size=%u\n",
 			       size);
@@ -1308,7 +1310,8 @@ static inline bool igt_can_allocate_thp(struct drm_i915_private *i915)
 
 static int igt_ppgtt_gemfs_huge(void *arg)
 {
-	struct drm_i915_private *i915 = arg;
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *i915 = ctx->i915;
 	struct drm_i915_gem_object *obj;
 	static const unsigned int sizes[] = {
 		SZ_2M,
@@ -1347,7 +1350,7 @@ static int igt_ppgtt_gemfs_huge(void *arg)
 			goto out_unpin;
 		}
 
-		err = igt_write_huge(obj);
+		err = igt_write_huge(ctx, obj);
 		if (err) {
 			pr_err("gemfs write-huge failed with size=%u\n",
 			       size);
@@ -1370,9 +1373,10 @@ out_put:
 
 static int igt_ppgtt_pin_update(void *arg)
 {
-	struct drm_i915_private *dev_priv = arg;
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *dev_priv = ctx->i915;
 	unsigned long supported = INTEL_INFO(dev_priv)->page_sizes;
-	struct i915_hw_ppgtt *ppgtt = dev_priv->kernel_context->ppgtt;
+	struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
 	struct drm_i915_gem_object *obj;
 	struct i915_vma *vma;
 	unsigned int flags = PIN_USER | PIN_OFFSET_FIXED;
@@ -1473,8 +1477,7 @@ static int igt_ppgtt_pin_update(void *arg)
 	 * land in the now stale 2M page.
 	 */
 
-	err = gpu_write(vma, dev_priv->kernel_context, dev_priv->engine[RCS],
-			0, 0xdeadbeaf);
+	err = gpu_write(vma, ctx, dev_priv->engine[RCS], 0, 0xdeadbeaf);
 	if (err)
 		goto out_unpin;
 
@@ -1492,9 +1495,9 @@ out_put:
 
 static int igt_tmpfs_fallback(void *arg)
 {
-	struct drm_i915_private *i915 = arg;
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *i915 = ctx->i915;
 	struct vfsmount *gemfs = i915->mm.gemfs;
-	struct i915_gem_context *ctx = i915->kernel_context;
 	struct i915_address_space *vm = ctx->ppgtt ? &ctx->ppgtt->base : &i915->ggtt.base;
 	struct drm_i915_gem_object *obj;
 	struct i915_vma *vma;
@@ -1549,8 +1552,8 @@ out_restore:
 
 static int igt_shrink_thp(void *arg)
 {
-	struct drm_i915_private *i915 = arg;
-	struct i915_gem_context *ctx = i915->kernel_context;
+	struct i915_gem_context *ctx = arg;
+	struct drm_i915_private *i915 = ctx->i915;
 	struct i915_address_space *vm = ctx->ppgtt ? &ctx->ppgtt->base : &i915->ggtt.base;
 	struct drm_i915_gem_object *obj;
 	struct i915_vma *vma;
@@ -1590,8 +1593,7 @@ static int igt_shrink_thp(void *arg)
 	if (err)
 		goto out_unpin;
 
-	err = gpu_write(vma, i915->kernel_context, i915->engine[RCS], 0,
-			0xdeadbeaf);
+	err = gpu_write(vma, ctx, i915->engine[RCS], 0, 0xdeadbeaf);
 	if (err)
 		goto out_unpin;
 
@@ -1700,6 +1702,8 @@ int i915_gem_huge_page_live_selftests(struct drm_i915_private *dev_priv)
 		SUBTEST(igt_ppgtt_gemfs_huge),
 		SUBTEST(igt_ppgtt_internal_huge),
 	};
+	struct drm_file *file;
+	struct i915_gem_context *ctx;
 	int err;
 
 	if (!USES_PPGTT(dev_priv)) {
@@ -1707,9 +1711,24 @@ int i915_gem_huge_page_live_selftests(struct drm_i915_private *dev_priv)
 		return 0;
 	}
 
+	file = mock_file(dev_priv);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
 	mutex_lock(&dev_priv->drm.struct_mutex);
-	err = i915_subtests(tests, dev_priv);
+
+	ctx = live_context(dev_priv, file);
+	if (IS_ERR(ctx)) {
+		err = PTR_ERR(ctx);
+		goto out_unlock;
+	}
+
+	err = i915_subtests(tests, ctx);
+
+out_unlock:
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 
+	mock_file_free(dev_priv, file);
+
 	return err;
 }