[PATCH] drm/i915: Add new vGPU cap info bit VGT_CAPS_HUGE_GTT

[changbin.du at intel.com]

From: Changbin Du <changbin.du at intel.com>

This adds a new vGPU cap info bit VGT_CAPS_HUGE_GTT, which is to detect
whether the host supports shadowing of huge gtt pages. If host does
support it, remove the page sizes restriction for vGPU.

Signed-off-by: Changbin Du <changbin.du at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c    | 8 ++------
 drivers/gpu/drm/i915/i915_pvinfo.h | 1 +
 drivers/gpu/drm/i915/i915_vgpu.h   | 6 ++++++
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 484354f..e0ddfa1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5355,12 +5355,8 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 {
 	int ret;
 
-	/*
-	 * We need to fallback to 4K pages since gvt gtt handling doesn't
-	 * support huge page entries - we will need to check either hypervisor
-	 * mm can support huge guest page or just do emulation in gvt.
-	 */
-	if (intel_vgpu_active(dev_priv))
+	/* We need to fallback to 4K pages if host doesn't support huge gtt. */
+	if (intel_vgpu_active(dev_priv) && !intel_vgpu_has_huge_gtt(dev_priv))
 		mkwrite_device_info(dev_priv)->page_sizes =
 			I915_GTT_PAGE_SIZE_4K;
 
diff --git a/drivers/gpu/drm/i915/i915_pvinfo.h b/drivers/gpu/drm/i915/i915_pvinfo.h
index 195203f..55bde4a 100644
--- a/drivers/gpu/drm/i915/i915_pvinfo.h
+++ b/drivers/gpu/drm/i915/i915_pvinfo.h
@@ -54,6 +54,7 @@ enum vgt_g2v_type {
  */
 #define VGT_CAPS_FULL_48BIT_PPGTT	BIT(2)
 #define VGT_CAPS_HWSP_EMULATION		BIT(3)
+#define VGT_CAPS_HUGE_GTT		BIT(4)
 
 struct vgt_if {
 	u64 magic;		/* VGT_MAGIC */
diff --git a/drivers/gpu/drm/i915/i915_vgpu.h b/drivers/gpu/drm/i915/i915_vgpu.h
index bb83384..551acc3 100644
--- a/drivers/gpu/drm/i915/i915_vgpu.h
+++ b/drivers/gpu/drm/i915/i915_vgpu.h
@@ -36,6 +36,12 @@ intel_vgpu_has_hwsp_emulation(struct drm_i915_private *dev_priv)
 	return dev_priv->vgpu.caps & VGT_CAPS_HWSP_EMULATION;
 }
 
+static inline bool
+intel_vgpu_has_huge_gtt(struct drm_i915_private *dev_priv)
+{
+	return dev_priv->vgpu.caps & VGT_CAPS_HUGE_GTT;
+}
+
 int intel_vgt_balloon(struct drm_i915_private *dev_priv);
 void intel_vgt_deballoon(struct drm_i915_private *dev_priv);
 
-- 
2.7.4