[PATCH v2 2/4] drm/i915/gvt: Select appropriate mmio list at initialization time

[Du, Changbin]

On Tue, Dec 05, 2017 at 11:46:22AM +0800, Zhenyu Wang wrote:
 >  static u32 gen9_render_mocs[I915_NUM_ENGINES][64];
> > @@ -282,21 +276,14 @@ static void switch_mmio_to_vgpu(struct intel_vgpu *vgpu, int ring_id)
> >  	u32 inhibit_mask =
> >  		_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT);
> >  	i915_reg_t last_reg = _MMIO(0);
> > -	struct render_mmio *mmio;
> > +	struct engine_mmio *mmio;
> >  	u32 v;
> > -	int i, array_size;
> >  
> > -	if (IS_SKYLAKE(vgpu->gvt->dev_priv)
> > -		|| IS_KABYLAKE(vgpu->gvt->dev_priv)) {
> > -		mmio = gen9_render_mmio_list;
> > -		array_size = ARRAY_SIZE(gen9_render_mmio_list);
> > +	if (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv))
> >  		load_mocs(vgpu, ring_id);
> > -	} else {
> > -		mmio = gen8_render_mmio_list;
> > -		array_size = ARRAY_SIZE(gen8_render_mmio_list);
> > -	}
> >  
> > -	for (i = 0; i < array_size; i++, mmio++) {
> > +	mmio = vgpu->gvt->engine_mmio_list;
> > +	while (i915_mmio_reg_offset((mmio++)->reg)) {
> >  		if (mmio->ring_id != ring_id)
> >  			continue;
> 
> Not safe to check end of the list and this will try to exceed the list?
> Seems wrong to me. Either use size of the list or mark array 0 end then
> check mmio pointer.
>
It will not exceed the list. The last mmio item is termination mark.
 
> -- 
> Open Source Technology Center, Intel ltd.
> 
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-- 
Thanks,
Changbin Du