drm/i915: Always enable execlists on BDW for vgpu

Broadwell hardware supports both ring buffer mode and execlist mode.
When i915 runs inside a VM with Intel GVT-g, we allow execlist mode
only.

The main reason of EXECLIST only is that GVT-g does not support the
dynamic mode switch between ring buffer mode and execlist mode when
running multiple virtual machines.

v2:
- Adjust the position of vgpu check in sanitize function (Joonas)
- Add vgpu error check in context initialization. (Joonas, Daniel)

Signed-off-by: Zhiyuan Lv <zhiyuan.lv@intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 8e893b354bccdfb5205dea4b4e3559d02225fe54..74aa0c9929ba3fe3fc2cc22230b4f16421ecf37e 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -332,6 +332,13 @@ int i915_gem_context_init(struct drm_device *dev)
        if (WARN_ON(dev_priv->ring[RCS].default_context))
                return 0;
 
+       if (intel_vgpu_active(dev) && HAS_LOGICAL_RING_CONTEXTS(dev)) {
+               if (!i915.enable_execlists) {
+                       DRM_INFO("Only EXECLIST mode is supported in vgpu.\n");
+                       return -EINVAL;
+               }
+       }
+
        if (i915.enable_execlists) {
                /* NB: intentionally left blank. We will allocate our own
                 * backing objects as we need them, thank you very much */

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 258af9b3f76551b79207b38121f471172d0d7e21..e9520afc2033bf39c8ac319bfd064d987cd9485e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -236,6 +236,12 @@ int intel_sanitize_enable_execlists(struct drm_device *dev, int enable_execlists
 {
        WARN_ON(i915.enable_ppgtt == -1);
 
+       /* On platforms with execlist available, vGPU will only
+        * support execlist mode, no ring buffer mode.
+        */
+       if (HAS_LOGICAL_RING_CONTEXTS(dev) && intel_vgpu_active(dev))
+               return 1;
+
        if (INTEL_INFO(dev)->gen >= 9)
                return 1;