[PATCH v2 8/8] drm/i915: Support alias ppgtt in VM if ppgtt is enabled

Yu Zhang
2014-10-17T06:06:06Z

The current XenGT only supports alias ppgtt. And the emulation
is done in XenGT host by first trapping PP_DIR_BASE mmio
accesses. Updating PP_DIR_BASE by using instructions such as
MI_LOAD_REGISTER_IMM are hard to detect and are not supported
in current XenGT. Therefore this patch also added a new callback
routine - vgpu_mm_switch() to set the PP_DIR_BASE by mmio writes.

v2:
take Chris' comments:
- move the code into sanitize_enable_ppgtt()

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Jike Song <jike.song@intel.com>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 90757ab..a731896 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -197,6 +197,9 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
if (IS_GEN8(dev))
has_full_ppgtt = false; /* XXX why? */

+ if (intel_vgpu_active(dev))
+ has_full_ppgtt = false; /* emulation is too hard */
+
if (enable_ppgtt == 0 || !has_aliasing_ppgtt)
return 0;

@@ -886,6 +889,16 @@ static int hsw_mm_switch(struct i915_hw_ppgtt *ppgtt,
return 0;
}

+static int vgpu_mm_switch(struct i915_hw_ppgtt *ppgtt,
+ struct intel_engine_cs *ring)
+{
+ struct drm_i915_private *dev_priv = to_i915(ppgtt->base.dev);
+
+ I915_WRITE(RING_PP_DIR_DCLV(ring), PP_DIR_DCLV_2G);
+ I915_WRITE(RING_PP_DIR_BASE(ring), get_pd_offset(ppgtt));
+ return 0;
+}
+
static int gen7_mm_switch(struct i915_hw_ppgtt *ppgtt,
struct intel_engine_cs *ring)
{
@@ -1212,6 +1225,9 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
} else
BUG();

+ if (intel_vgpu_active(dev))
+ ppgtt->switch_mm = vgpu_mm_switch;
+
ret = gen6_ppgtt_alloc(ppgtt);
if (ret)
return ret;
--
1.9.1