[PATCH] drm/i915/gvt: Add the support of HUC_STATUS2 reg emulation for Guest VGPU

[Zhenyu Wang]

On 2018.03.28 08:49:48 +0800, Zhao, Yakui wrote:
> 
> 
> On 2018年03月27日 15:27, Zhenyu Wang wrote:
> > On 2018.03.27 14:03:39 +0800, Zhao, Yakui wrote:
> > > > > > > diff --git a/drivers/gpu/drm/i915/gvt/mmio.c b/drivers/gpu/drm/i915/gvt/mmio.c
> > > > > > > index 11b71b3..7cf972d 100644
> > > > > > > --- a/drivers/gpu/drm/i915/gvt/mmio.c
> > > > > > > +++ b/drivers/gpu/drm/i915/gvt/mmio.c
> > > > > > > @@ -235,6 +235,7 @@ void intel_vgpu_reset_mmio(struct intel_vgpu *vgpu, bool dmlr)
> > > > > > >     	struct intel_gvt *gvt = vgpu->gvt;
> > > > > > >     	const struct intel_gvt_device_info *info = &gvt->device_info;
> > > > > > >     	void  *mmio = gvt->firmware.mmio;
> > > > > > > +	struct drm_i915_private *dev_priv = gvt->dev_priv;
> > > > > > >     	if (dmlr) {
> > > > > > >     		memcpy(vgpu->mmio.vreg, mmio, info->mmio_size);
> > > > > > > @@ -256,6 +257,11 @@ void intel_vgpu_reset_mmio(struct intel_vgpu *vgpu, bool dmlr)
> > > > > > >     		memcpy(vgpu->mmio.sreg, mmio, GVT_GEN8_MMIO_RESET_OFFSET);
> > > > > > >     	}
> > > > > > > +	if (HAS_HUC_UCODE(dev_priv)) {
> > > > 
> > > > maybe use USES_HUC()? so only read hw value when huc is loaded, otherwise can just skip.
> > > 
> > > The status of Huc loading only depends on the value of HUC_STATUS2 reg. (The
> > > dev_priv->huc_fw.load_status can't reflect the status of Huc as it needs the
> > > Guc authentication).
> > > 
> > > So it is checked on the platforms that supports the Guc/Huc.
> > > How do you think?
> > > 
> > 
> > I think USES_HUC() just check if huc fw is available for load, which
> > should be the state that we want to check huc fw status. And looks
> > HAS_HUC_UCODE() has no user within i915 code at all? I'm not clear
> > on that history maybe we should not use it anymore.
> > 
> 
> The USES_HUC macro will use the module parameter of i915.enable_guc to check
> whether the HUC is needed. And now it is used to control whether the Huc FW
> is loaded.
> 
> It is also ok to use the USES_HUC in the function of intel_vgpu_reset_mmio.
> 
> I will use the macro of USES_HUC to update the patch.
> 
> BTW:
>    For the real handler of HUC_STATUS2 reg: As it is one read-only register
> and not changed after initialization, I think that it can be initialized
> only once at the vgpu reset time.
>    How do you think?
> 

Still want a handler as looks that reg also contains some state info
that might need to be handled, as should not just expect what current
guest driver behavior is, but consider correct emulated state from hw.

-- 
Open Source Technology Center, Intel ltd.

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