Re: [PATCH 7/8] drm/i915/huc: Support HuC authentication

["Srivatsa, Anusha" <anusha.srivatsa@intel.com>]

>-----Original Message-----
>From: Chris Wilson [mailto:chris@chris-wilson.co.uk]
>Sent: Thursday, December 22, 2016 3:30 PM
>To: Srivatsa, Anusha <anusha.srivatsa@intel.com>
>Cc: intel-gfx@lists.freedesktop.org; Alex Dai <yu.dai@intel.com>; Peter Antoine
><peter.antoine@intel.com>
>Subject: Re: [Intel-gfx] [PATCH 7/8] drm/i915/huc: Support HuC authentication
>
>On Thu, Dec 22, 2016 at 03:12:23PM -0800, Anusha Srivatsa wrote:
>> +void intel_guc_auth_huc(struct drm_i915_private *dev_priv) {
>> +	struct intel_guc *guc = &dev_priv->guc;
>> +	struct intel_huc *huc = &dev_priv->huc;
>> +	struct i915_vma *vma;
>> +	int ret;
>> +	u32 data[2];
>> +
>> +	/* Bypass the case where there is no HuC firmware */
>> +	if (huc->fw.fetch_status == INTEL_UC_FIRMWARE_NONE ||
>> +		huc->fw.load_status == INTEL_UC_FIRMWARE_NONE)
>> +		return;
>> +
>> +	if (guc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS) {
>> +		DRM_ERROR("HuC: GuC fw wasn't loaded. Can't
>authenticate\n");
>> +		return;
>> +	}
>> +
>> +	if (huc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS) {
>> +		DRM_ERROR("HuC: fw wasn't loaded. Nothing to
>authenticate\n");
>> +		return;
>> +	}
>> +
>> +	vma = i915_gem_object_ggtt_pin(huc->fw.uc_fw_obj, NULL, 0, 0, 0);
>> +	if (IS_ERR(vma)) {
>> +		DRM_DEBUG_DRIVER("pin failed %d\n", (int)PTR_ERR(vma));
>> +		return;
>> +	}
>> +
>> +
>> +	/* Invalidate GuC TLB to let GuC take the latest updates to GTT. */
>> +	I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
>
>Still working on stopping this from frequently popping up in code outside of the
>GTT routines.
So, basically beautify the code such that the GTT routines do not pop out in non GTT parts of code. Correct? 
>
>> +	/* Specify auth action and where public signature is. */
>> +	data[0] = INTEL_GUC_ACTION_AUTHENTICATE_HUC;
>> +	data[1] = i915_ggtt_offset(vma) + huc->fw.rsa_offset;
>> +
>> +	ret = intel_guc_send(guc, data, ARRAY_SIZE(data));
>> +	if (ret) {
>> +		DRM_ERROR("HuC: GuC did not ack Auth request\n");
>> +		goto out;
>> +	}
>> +
>> +	/* Check authentication status, it should be done by now */
>> +	ret = wait_for((I915_READ(HUC_STATUS2) & HUC_FW_VERIFIED) > 0,
>50);
>
>ret = intel_wait_for_register(dev_priv,
>			      HUC_STATUS2,
>			      HUC_FW_VERIFIED,
>			      HUC_FW_VERIFIED,
>			      50);
>
>wait_for() is a rather large macro, and intel_wait_for_register() employs the spin
>then sleep optimisation for quick responses.

Thankyou for bringing this to my notice. 

Anusha

>-Chris
>
>--
>Chris Wilson, Intel Open Source Technology Centre
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