1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
new file mode 100644
index 000000000000..e2314ad9546d
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2020 Intel Corporation.
+ */
+#include <linux/workqueue.h>
+#include "intel_pxp.h"
+#include "intel_pxp_irq.h"
+#include "intel_pxp_session.h"
+#include "intel_pxp_tee.h"
+#include "gem/i915_gem_context.h"
+#include "gt/intel_context.h"
+#include "i915_drv.h"
+
+/**
+ * DOC: PXP
+ *
+ * PXP (Protected Xe Path) is a feature available in Gen12 and newer platforms.
+ * It allows execution and flip to display of protected (i.e. encrypted)
+ * objects. The SW support is enabled via the CONFIG_DRM_I915_PXP kconfig.
+ *
+ * Objects can opt-in to PXP encryption at creation time via the
+ * I915_GEM_CREATE_EXT_PROTECTED_CONTENT create_ext flag. For objects to be
+ * correctly protected they must be used in conjunction with a context created
+ * with the I915_CONTEXT_PARAM_PROTECTED_CONTENT flag. See the documentation
+ * of those two uapi flags for details and restrictions.
+ *
+ * Protected objects are tied to a pxp session; currently we only support one
+ * session, which i915 manages and whose index is available in the uapi
+ * (I915_PROTECTED_CONTENT_DEFAULT_SESSION) for use in instructions targeting
+ * protected objects.
+ * The session is invalidated by the HW when certain events occur (e.g.
+ * suspend/resume). When this happens, all the objects that were used with the
+ * session are marked as invalid and all contexts marked as using protected
+ * content are banned. Any further attempt at using them in an execbuf call is
+ * rejected, while flips are converted to black frames.
+ *
+ * Some of the PXP setup operations are performed by the Management Engine,
+ * which is handled by the mei driver; communication between i915 and mei is
+ * performed via the mei_pxp component module.
+ */
+
+struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp)
+{
+	return container_of(pxp, struct intel_gt, pxp);
+}
+
+bool intel_pxp_is_active(const struct intel_pxp *pxp)
+{
+	return pxp->arb_is_valid;
+}
+
+/* KCR register definitions */
+#define KCR_INIT _MMIO(0x320f0)
+/* Setting KCR Init bit is required after system boot */
+#define KCR_INIT_ALLOW_DISPLAY_ME_WRITES REG_BIT(14)
+
+static void kcr_pxp_enable(struct intel_gt *gt)
+{
+	intel_uncore_write(gt->uncore, KCR_INIT,
+			   _MASKED_BIT_ENABLE(KCR_INIT_ALLOW_DISPLAY_ME_WRITES));
+}
+
+static void kcr_pxp_disable(struct intel_gt *gt)
+{
+	intel_uncore_write(gt->uncore, KCR_INIT,
+			   _MASKED_BIT_DISABLE(KCR_INIT_ALLOW_DISPLAY_ME_WRITES));
+}
+
+static int create_vcs_context(struct intel_pxp *pxp)
+{
+	static struct lock_class_key pxp_lock;
+	struct intel_gt *gt = pxp_to_gt(pxp);
+	struct intel_engine_cs *engine;
+	struct intel_context *ce;
+	int i;
+
+	/*
+	 * Find the first VCS engine present. We're guaranteed there is one
+	 * if we're in this function due to the check in has_pxp
+	 */
+	for (i = 0, engine = NULL; !engine; i++)
+		engine = gt->engine_class[VIDEO_DECODE_CLASS][i];
+
+	GEM_BUG_ON(!engine || engine->class != VIDEO_DECODE_CLASS);
+
+	ce = intel_engine_create_pinned_context(engine, engine->gt->vm, SZ_4K,
+						I915_GEM_HWS_PXP_ADDR,
+						&pxp_lock, "pxp_context");
+	if (IS_ERR(ce)) {
+		drm_err(&gt->i915->drm, "failed to create VCS ctx for PXP\n");
+		return PTR_ERR(ce);
+	}
+
+	pxp->ce = ce;
+
+	return 0;
+}
+
+static void destroy_vcs_context(struct intel_pxp *pxp)
+{
+	intel_engine_destroy_pinned_context(fetch_and_zero(&pxp->ce));
+}
+
+void intel_pxp_init(struct intel_pxp *pxp)
+{
+	struct intel_gt *gt = pxp_to_gt(pxp);
+	int ret;
+
+	if (!HAS_PXP(gt->i915))
+		return;
+
+	mutex_init(&pxp->tee_mutex);
+
+	/*
+	 * we'll use the completion to check if there is a termination pending,
+	 * so we start it as completed and we reinit it when a termination
+	 * is triggered.
+	 */
+	init_completion(&pxp->termination);
+	complete_all(&pxp->termination);
+
+	mutex_init(&pxp->arb_mutex);
+	INIT_WORK(&pxp->session_work, intel_pxp_session_work);
+
+	ret = create_vcs_context(pxp);
+	if (ret)
+		return;
+
+	ret = intel_pxp_tee_component_init(pxp);
+	if (ret)
+		goto out_context;
+
+	drm_info(&gt->i915->drm, "Protected Xe Path (PXP) protected content support initialized\n");
+
+	return;
+
+out_context:
+	destroy_vcs_context(pxp);
+}
+
+void intel_pxp_fini(struct intel_pxp *pxp)
+{
+	if (!intel_pxp_is_enabled(pxp))
+		return;
+
+	pxp->arb_is_valid = false;
+
+	intel_pxp_tee_component_fini(pxp);
+
+	destroy_vcs_context(pxp);
+}
+
+void intel_pxp_mark_termination_in_progress(struct intel_pxp *pxp)
+{
+	pxp->arb_is_valid = false;
+	reinit_completion(&pxp->termination);
+}
+
+static void pxp_queue_termination(struct intel_pxp *pxp)
+{
+	struct intel_gt *gt = pxp_to_gt(pxp);
+
+	/*
+	 * We want to get the same effect as if we received a termination
+	 * interrupt, so just pretend that we did.
+	 */
+	spin_lock_irq(&gt->irq_lock);
+	intel_pxp_mark_termination_in_progress(pxp);
+	pxp->session_events |= PXP_TERMINATION_REQUEST;
+	queue_work(system_unbound_wq, &pxp->session_work);
+	spin_unlock_irq(&gt->irq_lock);
+}
+
+/*
+ * the arb session is restarted from the irq work when we receive the
+ * termination completion interrupt
+ */
+int intel_pxp_start(struct intel_pxp *pxp)
+{
+	int ret = 0;
+
+	if (!intel_pxp_is_enabled(pxp))
+		return -ENODEV;
+
+	mutex_lock(&pxp->arb_mutex);
+
+	if (pxp->arb_is_valid)
+		goto unlock;
+
+	pxp_queue_termination(pxp);
+
+	if (!wait_for_completion_timeout(&pxp->termination,
+					msecs_to_jiffies(250))) {
+		ret = -ETIMEDOUT;
+		goto unlock;
+	}
+
+	/* make sure the compiler doesn't optimize the double access */
+	barrier();
+
+	if (!pxp->arb_is_valid)
+		ret = -EIO;
+
+unlock:
+	mutex_unlock(&pxp->arb_mutex);
+	return ret;
+}
+
+void intel_pxp_init_hw(struct intel_pxp *pxp)
+{
+	kcr_pxp_enable(pxp_to_gt(pxp));
+	intel_pxp_irq_enable(pxp);
+}
+
+void intel_pxp_fini_hw(struct intel_pxp *pxp)
+{
+	kcr_pxp_disable(pxp_to_gt(pxp));
+
+	intel_pxp_irq_disable(pxp);
+}
+
+int intel_pxp_key_check(struct intel_pxp *pxp,
+			struct drm_i915_gem_object *obj,
+			bool assign)
+{
+	if (!intel_pxp_is_active(pxp))
+		return -ENODEV;
+
+	if (!i915_gem_object_is_protected(obj))
+		return -EINVAL;
+
+	GEM_BUG_ON(!pxp->key_instance);
+
+	/*
+	 * If this is the first time we're using this object, it's not
+	 * encrypted yet; it will be encrypted with the current key, so mark it
+	 * as such. If the object is already encrypted, check instead if the
+	 * used key is still valid.
+	 */
+	if (!obj->pxp_key_instance && assign)
+		obj->pxp_key_instance = pxp->key_instance;
+
+	if (obj->pxp_key_instance != pxp->key_instance)
+		return -ENOEXEC;
+
+	return 0;
+}
+
+void intel_pxp_invalidate(struct intel_pxp *pxp)
+{
+	struct drm_i915_private *i915 = pxp_to_gt(pxp)->i915;
+	struct i915_gem_context *ctx, *cn;
+
+	/* ban all contexts marked as protected */
+	spin_lock_irq(&i915->gem.contexts.lock);
+	list_for_each_entry_safe(ctx, cn, &i915->gem.contexts.list, link) {
+		struct i915_gem_engines_iter it;
+		struct intel_context *ce;
+
+		if (!kref_get_unless_zero(&ctx->ref))
+			continue;
+
+		if (likely(!i915_gem_context_uses_protected_content(ctx))) {
+			i915_gem_context_put(ctx);
+			continue;
+		}
+
+		spin_unlock_irq(&i915->gem.contexts.lock);
+
+		/*
+		 * By the time we get here we are either going to suspend with
+		 * quiesced execution or the HW keys are already long gone and
+		 * in this case it is worthless to attempt to close the context
+		 * and wait for its execution. It will hang the GPU if it has
+		 * not already. So, as a fast mitigation, we can ban the
+		 * context as quick as we can. That might race with the
+		 * execbuffer, but currently this is the best that can be done.
+		 */
+		for_each_gem_engine(ce, i915_gem_context_lock_engines(ctx), it)
+			intel_context_ban(ce, NULL);
+		i915_gem_context_unlock_engines(ctx);
+
+		/*
+		 * The context has been banned, no need to keep the wakeref.
+		 * This is safe from races because the only other place this
+		 * is touched is context_release and we're holding a ctx ref
+		 */
+		if (ctx->pxp_wakeref) {
+			intel_runtime_pm_put(&i915->runtime_pm,
+					     ctx->pxp_wakeref);
+			ctx->pxp_wakeref = 0;
+		}
+
+		spin_lock_irq(&i915->gem.contexts.lock);
+		list_safe_reset_next(ctx, cn, link);
+		i915_gem_context_put(ctx);
+	}
+	spin_unlock_irq(&i915->gem.contexts.lock);
+}