Re: [PATCH v3 8/8] drm/i915: Support alias ppgtt in VM if ppgtt is enabled

Tvrtko Ursulin
2014-12-12T13:37:33Z

On 11/13/2014 12:02 PM, Yu Zhang wrote:
> The current Intel GVT-g only supports alias ppgtt. And the
> emulation is done in the 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 code. 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 2dfac13..55307eb 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -44,6 +44,9 @@ 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;
>
> @@ -733,6 +736,16 @@ 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)
> {
> @@ -1059,6 +1072,9 @@ 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;
>

Pending potential "checkpatch.pl --strict" fixes,

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>