[Intel-gfx] [PATCH] drm/i915/vgpu: Neuter forcewakes for VGPU more thouroughly

[Chris Wilson]

On Fri, Mar 10, 2017 at 09:57:47AM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> If we avoid initializing forcewake domains when running as
> a guest, and also use gen2 mmio accessors in that case, we
> can avoid the timer traffic and any looping through the
> forcewake code which is currently just so it can end up in
> the no-op forcewake implementation.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Weinan Li <weinan.z.li at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_uncore.c | 76 +++++++++++++------------------------
>  1 file changed, 27 insertions(+), 49 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index 71b9b387ad04..09f5f02d7901 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -138,13 +138,6 @@ fw_domains_put(struct drm_i915_private *dev_priv, enum forcewake_domains fw_doma
>  }
>  
>  static void
> -vgpu_fw_domains_nop(struct drm_i915_private *dev_priv,
> -		    enum forcewake_domains fw_domains)
> -{
> -	/* Guest driver doesn't need to takes care forcewake. */
> -}
> -
> -static void
>  fw_domains_posting_read(struct drm_i915_private *dev_priv)
>  {
>  	struct intel_uncore_forcewake_domain *d;
> @@ -1187,7 +1180,7 @@ static void fw_domain_init(struct drm_i915_private *dev_priv,
>  
>  static void intel_uncore_fw_domains_init(struct drm_i915_private *dev_priv)
>  {
> -	if (INTEL_INFO(dev_priv)->gen <= 5)
> +	if (INTEL_GEN(dev_priv) <= 5 || intel_vgpu_active(dev_priv))

Make these separate ifs, they aren't semantically related so be verbose.

>  		return;
>  
>  	if (IS_GEN9(dev_priv)) {
> @@ -1273,11 +1266,6 @@ static void intel_uncore_fw_domains_init(struct drm_i915_private *dev_priv)
>  			       FORCEWAKE, FORCEWAKE_ACK);
>  	}
>  
> -	if (intel_vgpu_active(dev_priv)) {
> -		dev_priv->uncore.funcs.force_wake_get = vgpu_fw_domains_nop;
> -		dev_priv->uncore.funcs.force_wake_put = vgpu_fw_domains_nop;
> -	}
> -
>  	/* All future platforms are expected to require complex power gating */
>  	WARN_ON(dev_priv->uncore.fw_domains == 0);
>  }
> @@ -1327,22 +1315,22 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
>  	dev_priv->uncore.pmic_bus_access_nb.notifier_call =
>  		i915_pmic_bus_access_notifier;
>  
> -	switch (INTEL_INFO(dev_priv)->gen) {
> -	default:
> -	case 9:
> -		ASSIGN_FW_DOMAINS_TABLE(__gen9_fw_ranges);
> -		ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
> -		ASSIGN_READ_MMIO_VFUNCS(fwtable);
> -		if (HAS_DECOUPLED_MMIO(dev_priv)) {
> -			dev_priv->uncore.funcs.mmio_readl =
> -						gen9_decoupled_read32;
> -			dev_priv->uncore.funcs.mmio_readq =
> -						gen9_decoupled_read64;
> -			dev_priv->uncore.funcs.mmio_writel =
> -						gen9_decoupled_write32;
> +	if (IS_GEN(dev_priv, 2, 4) || intel_vgpu_active(dev_priv)) {

Ok, this doesn't look too bad.

Do the gvt-g hosts in CI now provide coverage for us of vgpu paths?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre