drm/i915: Add TTM offset argument to mmap.

The FIXED mapping is only used for ttm, and tells userspace that the
mapping type is pre-defined. This disables the other type of mmap
offsets when discrete memory is used, so fix the selftests as well.

Document the struct as well, so it shows up in docbook.

Cc: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[mauld: Included minor fixes from the review comments]
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714122833.766586-1-maarten.lankhorst@linux.intel.com

3 files changed, 42 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index a90f796e85c0..2f3b7dc7b0e6 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -679,10 +679,16 @@ __assign_mmap_offset(struct drm_i915_gem_object *obj,
 		return -ENODEV;
 
 	if (obj->ops->mmap_offset)  {
+		if (mmap_type != I915_MMAP_TYPE_FIXED)
+			return -ENODEV;
+
 		*offset = obj->ops->mmap_offset(obj);
 		return 0;
 	}
 
+	if (mmap_type == I915_MMAP_TYPE_FIXED)
+		return -ENODEV;
+
 	if (mmap_type != I915_MMAP_TYPE_GTT &&
 	    !i915_gem_object_has_struct_page(obj) &&
 	    !i915_gem_object_has_iomem(obj))
@@ -727,7 +733,9 @@ i915_gem_dumb_mmap_offset(struct drm_file *file,
 {
 	enum i915_mmap_type mmap_type;
 
-	if (boot_cpu_has(X86_FEATURE_PAT))
+	if (HAS_LMEM(to_i915(dev)))
+		mmap_type = I915_MMAP_TYPE_FIXED;
+	else if (boot_cpu_has(X86_FEATURE_PAT))
 		mmap_type = I915_MMAP_TYPE_WC;
 	else if (!i915_ggtt_has_aperture(&to_i915(dev)->ggtt))
 		return -ENODEV;
@@ -798,6 +806,10 @@ i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
 		type = I915_MMAP_TYPE_UC;
 		break;
 
+	case I915_MMAP_OFFSET_FIXED:
+		type = I915_MMAP_TYPE_FIXED;
+		break;
+
 	default:
 		return -EINVAL;
 	}
@@ -968,6 +980,9 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 		vma->vm_ops = &vm_ops_cpu;
 		break;
 
+	case I915_MMAP_TYPE_FIXED:
+		GEM_WARN_ON(1);
+		fallthrough;
 	case I915_MMAP_TYPE_WB:
 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 		vma->vm_ops = &vm_ops_cpu;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index ef3de2ae9723..afbadfc5516b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -105,6 +105,7 @@ enum i915_mmap_type {
 	I915_MMAP_TYPE_WC,
 	I915_MMAP_TYPE_WB,
 	I915_MMAP_TYPE_UC,
+	I915_MMAP_TYPE_FIXED,
 };
 
 struct i915_mmap_offset {
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index fda017c19ef6..0b2b73d8a364 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -573,6 +573,14 @@ err:
 	return 0;
 }
 
+static enum i915_mmap_type default_mapping(struct drm_i915_private *i915)
+{
+	if (HAS_LMEM(i915))
+		return I915_MMAP_TYPE_FIXED;
+
+	return I915_MMAP_TYPE_GTT;
+}
+
 static bool assert_mmap_offset(struct drm_i915_private *i915,
 			       unsigned long size,
 			       int expected)
@@ -585,7 +593,7 @@ static bool assert_mmap_offset(struct drm_i915_private *i915,
 	if (IS_ERR(obj))
 		return expected && expected == PTR_ERR(obj);
 
-	ret = __assign_mmap_offset(obj, I915_MMAP_TYPE_GTT, &offset, NULL);
+	ret = __assign_mmap_offset(obj, default_mapping(i915), &offset, NULL);
 	i915_gem_object_put(obj);
 
 	return ret == expected;
@@ -689,7 +697,7 @@ static int igt_mmap_offset_exhaustion(void *arg)
 		goto out;
 	}
 
-	err = __assign_mmap_offset(obj, I915_MMAP_TYPE_GTT, &offset, NULL);
+	err = __assign_mmap_offset(obj, default_mapping(i915), &offset, NULL);
 	if (err) {
 		pr_err("Unable to insert object into reclaimed hole\n");
 		goto err_obj;
@@ -831,8 +839,14 @@ static int wc_check(struct drm_i915_gem_object *obj)
 
 static bool can_mmap(struct drm_i915_gem_object *obj, enum i915_mmap_type type)
 {
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	bool no_map;
 
+	if (HAS_LMEM(i915))
+		return type == I915_MMAP_TYPE_FIXED;
+	else if (type == I915_MMAP_TYPE_FIXED)
+		return false;
+
 	if (type == I915_MMAP_TYPE_GTT &&
 	    !i915_ggtt_has_aperture(&to_i915(obj->base.dev)->ggtt))
 		return false;
@@ -970,6 +984,8 @@ static int igt_mmap(void *arg)
 			err = __igt_mmap(i915, obj, I915_MMAP_TYPE_GTT);
 			if (err == 0)
 				err = __igt_mmap(i915, obj, I915_MMAP_TYPE_WC);
+			if (err == 0)
+				err = __igt_mmap(i915, obj, I915_MMAP_TYPE_FIXED);
 
 			i915_gem_object_put(obj);
 			if (err)
@@ -987,6 +1003,7 @@ static const char *repr_mmap_type(enum i915_mmap_type type)
 	case I915_MMAP_TYPE_WB: return "wb";
 	case I915_MMAP_TYPE_WC: return "wc";
 	case I915_MMAP_TYPE_UC: return "uc";
+	case I915_MMAP_TYPE_FIXED: return "fixed";
 	default: return "unknown";
 	}
 }
@@ -1100,6 +1117,8 @@ static int igt_mmap_access(void *arg)
 			err = __igt_mmap_access(i915, obj, I915_MMAP_TYPE_WC);
 		if (err == 0)
 			err = __igt_mmap_access(i915, obj, I915_MMAP_TYPE_UC);
+		if (err == 0)
+			err = __igt_mmap_access(i915, obj, I915_MMAP_TYPE_FIXED);
 
 		i915_gem_object_put(obj);
 		if (err)
@@ -1241,6 +1260,8 @@ static int igt_mmap_gpu(void *arg)
 		err = __igt_mmap_gpu(i915, obj, I915_MMAP_TYPE_GTT);
 		if (err == 0)
 			err = __igt_mmap_gpu(i915, obj, I915_MMAP_TYPE_WC);
+		if (err == 0)
+			err = __igt_mmap_gpu(i915, obj, I915_MMAP_TYPE_FIXED);
 
 		i915_gem_object_put(obj);
 		if (err)
@@ -1396,6 +1417,8 @@ static int igt_mmap_revoke(void *arg)
 		err = __igt_mmap_revoke(i915, obj, I915_MMAP_TYPE_GTT);
 		if (err == 0)
 			err = __igt_mmap_revoke(i915, obj, I915_MMAP_TYPE_WC);
+		if (err == 0)
+			err = __igt_mmap_revoke(i915, obj, I915_MMAP_TYPE_FIXED);
 
 		i915_gem_object_put(obj);
 		if (err)