tests/i915/pxp: test_pxp_stale_buf_optout_execution requires arb session

Subtest 'test_pxp_stale_buf_optout_execution' when run on its own,
could be executing without the PXP Arb session being alive. This
would result in the termination trigger to fail (when writing to
the pxp termination debugfs).

Create a background protected context to start the Arb session so
the simulated termination will succeed.

   v2: - use create_ctx_with_params instead of prepare_exec_assets
         for the background pxp context (Daniele)

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

tests/i915/gem_pxp.c

@@ -933,6 +933,27 @@ static void test_pxp_stale_buf_optout_execution(int i915)
 {
 	int ret;
 	struct simple_exec_assets data = {0};
+	uint32_t tmpctx;
+
+	/*
+	 * NOTE: this subtest creates a non-protected context
+	 * for submissions that uses a protected buffer. The UAPI
+	 * requirement dictates that gem_exec_buf will not fail
+	 * if a teardown occurs since the context was not protected,
+	 * despite the buffer being protected. However, the teardown
+	 * is simulated using the pxp termination debugfs which will
+	 * fail if PXP arb session is not active. Coincidentially
+	 * this will likely not happen when running all the subtests
+	 * together but if we execute this specific subtest on its own
+	 * and we didn't previously create an ARB session or if runtime
+	 * power management forced the arb session into invalid state,
+	 * we will not have active ARB session and thus the termination debugfs
+	 * will fail and cause an assertion. That said, we need to
+	 * create a background protected context (uninvolved with
+	 * the intent of the subtest) to ensure ARB session is alive.
+	 */
+	ret = create_ctx_with_params(i915, true, true, true, false, &tmpctx);
+	igt_assert(ret == 0);
 
 	/*
 	 * Use a normal context for testing opt-out behavior
@@ -948,6 +969,7 @@ static void test_pxp_stale_buf_optout_execution(int i915)
 	igt_assert_f((ret == 0), "Opt-out-execution with stale pxp buffer didn't succeed\n");
 
 	free_exec_assets(i915, &data);
+	gem_context_destroy(i915, tmpctx);
 }
 
 static void test_pxp_pwrcycle_staleasset_execution(int i915, struct powermgt_data *pm)