[Intel-gfx] [PATCH v4] drm/i915/gvt: return the correct usable aperture size under gvt environment

[Weinan Li]

I915_GEM_GET_APERTURE ioctl is used to probe aperture size from userspace.
In gvt environment, each vm only use the ballooned part of aperture, so we
should return the correct available aperture size exclude the reserved part
by balloon.

v2: add 'reserved' in struct i915_address_space to record the reserved size
in ggtt.

v3: remain aper_size as total, adjust aper_available_size exclude reserved
and pinned. UMD driver need to adjust the max allocation size according to
the available aperture size but not total size. KMD return the correct
usable aperture size any time.

v4: add onion teardown to balloon and deballoon to make sure the reserved
stays correct. Code style refine.

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Signed-off-by: Weinan Li <weinan.z.li at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c     | 4 ++--
 drivers/gpu/drm/i915/i915_gem_gtt.h | 1 +
 drivers/gpu/drm/i915/i915_vgpu.c    | 8 +++++++-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 33fb11c..8d8d9c0 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -156,8 +156,8 @@ int i915_mutex_lock_interruptible(struct drm_device *dev)
 	mutex_unlock(&dev->struct_mutex);
 
 	args->aper_size = ggtt->base.total;
-	args->aper_available_size = args->aper_size - pinned;
-
+	args->aper_available_size = args->aper_size -
+		ggtt->base.reserved - pinned;
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index fb15684..da9aa9f 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -255,6 +255,7 @@ struct i915_address_space {
 	struct drm_i915_file_private *file;
 	struct list_head global_link;
 	u64 total;		/* size addr space maps (ex. 2GB for ggtt) */
+	u64 reserved;		/* size addr space reserved */
 
 	bool closed;
 
diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
index 4ab8a97..25bed9b 100644
--- a/drivers/gpu/drm/i915/i915_vgpu.c
+++ b/drivers/gpu/drm/i915/i915_vgpu.c
@@ -109,8 +109,10 @@ void intel_vgt_deballoon(struct drm_i915_private *dev_priv)
 	DRM_DEBUG("VGT deballoon.\n");
 
 	for (i = 0; i < 4; i++) {
-		if (bl_info.space[i].allocated)
+		if (bl_info.space[i].allocated) {
+			dev_priv->ggtt.base.reserved -= bl_info.space[i].size;
 			drm_mm_remove_node(&bl_info.space[i]);
+		}
 	}
 
 	memset(&bl_info, 0, sizeof(bl_info));
@@ -216,6 +218,7 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 
 		if (ret)
 			goto err;
+		ggtt->base.reserved += bl_info.space[2].size;
 	}
 
 	if (unmappable_end < ggtt_end) {
@@ -223,6 +226,7 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 					unmappable_end, ggtt_end);
 		if (ret)
 			goto err;
+		ggtt->base.reserved += bl_info.space[3].size;
 	}
 
 	/* Mappable graphic memory ballooning */
@@ -232,6 +236,7 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 
 		if (ret)
 			goto err;
+		ggtt->base.reserved += bl_info.space[0].size;
 	}
 
 	if (mappable_end < ggtt->mappable_end) {
@@ -240,6 +245,7 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 
 		if (ret)
 			goto err;
+		ggtt->base.reserved += bl_info.space[1].size;
 	}
 
 	DRM_INFO("VGT balloon successfully\n");
-- 
1.9.1