[Intel-gfx] [PATCH v2 2/2] drm/i915: Invalidate the guc ggtt TLB upon insertion

[Tvrtko Ursulin]

On 01/12/2016 09:46, Chris Wilson wrote:
> Move the GuC invalidation of its ggtt TLB to where we perform the ggtt
> modification rather than proliferate it into all the callers of the
> insert (which may or may not in fact have to do the insertion).
>
> v2: Just do the guc invalidate unconditionally, (afaict) it has no impact
> without the guc loaded on gen8+

Why do you find it tempting to do it unconditionally? I would rather not 
touch it on gen8 at all and would also prefer the conditional flush in gen9.

Regards,

Tvrtko

> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch> # v1
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch> # v1
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c        | 12 ++++++++----
>  drivers/gpu/drm/i915/i915_guc_submission.c |  3 ---
>  drivers/gpu/drm/i915/intel_guc_loader.c    |  3 ---
>  drivers/gpu/drm/i915/intel_lrc.c           |  6 ------
>  4 files changed, 8 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 02fb063302bf..dccc4d0eef88 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -2387,6 +2387,12 @@ static void gen8_set_pte(void __iomem *addr, gen8_pte_t pte)
>  	writeq(pte, addr);
>  }
>
> +static void gen8_ggtt_invalidate(struct drm_i915_private *dev_priv)
> +{
> +	I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
> +	I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
> +}
> +
>  static void gen8_ggtt_insert_page(struct i915_address_space *vm,
>  				  dma_addr_t addr,
>  				  uint64_t offset,
> @@ -2400,8 +2406,7 @@ static void gen8_ggtt_insert_page(struct i915_address_space *vm,
>
>  	gen8_set_pte(pte, gen8_pte_encode(addr, level));
>
> -	I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
> -	POSTING_READ(GFX_FLSH_CNTL_GEN6);
> +	gen8_ggtt_invalidate(dev_priv);
>  }
>
>  static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
> @@ -2438,8 +2443,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
>  	 * want to flush the TLBs only after we're certain all the PTE updates
>  	 * have finished.
>  	 */
> -	I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
> -	POSTING_READ(GFX_FLSH_CNTL_GEN6);
> +	gen8_ggtt_invalidate(dev_priv);
>  }
>
>  struct insert_entries {
> diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
> index 58413803ba3c..ef8c18d61a0f 100644
> --- a/drivers/gpu/drm/i915/i915_guc_submission.c
> +++ b/drivers/gpu/drm/i915/i915_guc_submission.c
> @@ -589,9 +589,6 @@ static struct i915_vma *guc_allocate_vma(struct intel_guc *guc, u32 size)
>  		goto err;
>  	}
>
> -	/* Invalidate GuC TLB to let GuC take the latest updates to GTT. */
> -	I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
> -
>  	return vma;
>
>  err:
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index a330fa499384..4fb1037faad1 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -366,9 +366,6 @@ static int guc_ucode_xfer(struct drm_i915_private *dev_priv)
>  		return PTR_ERR(vma);
>  	}
>
> -	/* Invalidate GuC TLB to let GuC take the latest updates to GTT. */
> -	I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
> -
>  	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
>
>  	/* init WOPCM */
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index b2c0d509e191..48fc93dadb40 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -874,12 +874,6 @@ static int intel_lr_context_pin(struct i915_gem_context *ctx,
>
>  	ce->state->obj->mm.dirty = true;
>
> -	/* Invalidate GuC TLB. */
> -	if (i915.enable_guc_submission) {
> -		struct drm_i915_private *dev_priv = ctx->i915;
> -		I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
> -	}
> -
>  	i915_gem_context_get(ctx);
>  	return 0;
>
>