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

From: Chris Wilson <chris@chris-wilson.co.uk>
To: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: intel-gfx@lists.freedesktop.org, Alex Dai <yu.dai@intel.com>,
	Peter Antoine <peter.antoine@intel.com>
Subject: Re: [PATCH 7/8] drm/i915/huc: Support HuC authentication
Date: Thu, 22 Dec 2016 23:30:14 +0000	[thread overview]
Message-ID: <20161222233014.GG11865@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <1482448344-6505-8-git-send-email-anusha.srivatsa@intel.com>

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.

> +	/* 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.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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