[PATCH v3 3/3] drm/i915/gt/pxp: User PXP contexts requires runalone bit in lrc

[Alan Previn]

On Meteorlake onwards, HW specs require that all user contexts that
run on render or compute engines and require PXP must enforce
run-alone bit in lrc. Add this enforcement for protected contexts.

Signed-off-by: Alan Previn <alan.previn.teres.alexis at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 957d0aeb0c02..c7cab1c727ac 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -845,6 +845,29 @@ lrc_setup_indirect_ctx(u32 *regs,
 		lrc_ring_indirect_offset_default(engine) << 6;
 }
 
+static bool ctx_needs_runalone(const struct intel_context *ce)
+{
+	struct i915_gem_context *gem_ctx;
+	bool ctx_is_protected = false;
+
+	/*
+	 * On MTL and newer platforms, protected contexts require setting
+	 * the LRC run-alone bit or else the encryption will not happen.
+	 */
+	if (GRAPHICS_VER_FULL(ce->engine->i915) >= IP_VER(12, 70) &&
+	    (ce->engine->class == COMPUTE_CLASS || ce->engine->class == RENDER_CLASS)) {
+		rcu_read_lock();
+		gem_ctx = rcu_dereference(ce->gem_context);
+		if (gem_ctx)
+			ctx_is_protected = gem_ctx->uses_protected_content;
+		rcu_read_unlock();
+		if (ctx_is_protected)
+			return true;
+	}
+
+	return false;
+}
+
 static void init_common_regs(u32 * const regs,
 			     const struct intel_context *ce,
 			     const struct intel_engine_cs *engine,
@@ -860,6 +883,8 @@ static void init_common_regs(u32 * const regs,
 	if (GRAPHICS_VER(engine->i915) < 11)
 		ctl |= _MASKED_BIT_DISABLE(CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT |
 					   CTX_CTRL_RS_CTX_ENABLE);
+	if (ctx_needs_runalone(ce))
+		ctl |= _MASKED_BIT_ENABLE(BIT(7));
 	regs[CTX_CONTEXT_CONTROL] = ctl;
 
 	regs[CTX_TIMESTAMP] = ce->stats.runtime.last;
-- 
2.39.0