[PATCH v11 09/10] drm/i915/selftest: maintain context ref during reset test

[Robert Beckett]

Commit "bcb9aa45d5a0 Revert "drm/i915: Hold reference to intel_context over 
life of i915_request""
Stopped requests from maintaining a ref on the context.
This caused the contexts to be freed, releasing stolen memory while
under test, leading to false positive detection of stolen corruption.
Fix this by maintaining a ref on the contexts until testing is complete.

Signed-off-by: Robert Beckett <bob.beck...@collabora.com>
---
 drivers/gpu/drm/i915/gt/selftest_reset.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_reset.c 
b/drivers/gpu/drm/i915/gt/selftest_reset.c
index 55f3b34e5f6e..ba536e8a2e32 100644
--- a/drivers/gpu/drm/i915/gt/selftest_reset.c
+++ b/drivers/gpu/drm/i915/gt/selftest_reset.c
@@ -6,6 +6,7 @@
 #include <linux/crc32.h>
 
 #include "gem/i915_gem_stolen.h"
+#include "gt/intel_gt.h"
 
 #include "i915_memcpy.h"
 #include "i915_selftest.h"
@@ -26,6 +27,7 @@ __igt_reset_stolen(struct intel_gt *gt,
        intel_wakeref_t wakeref;
        enum intel_engine_id id;
        struct igt_spinner spin;
+       struct intel_context *contexts[I915_NUM_ENGINES] = {0};
        long max, count;
        void *tmp;
        u32 *crc;
@@ -71,12 +73,12 @@ __igt_reset_stolen(struct intel_gt *gt,
                        goto err_spin;
                }
                rq = igt_spinner_create_request(&spin, ce, MI_ARB_CHECK);
-               intel_context_put(ce);
                if (IS_ERR(rq)) {
                        err = PTR_ERR(rq);
                        goto err_spin;
                }
                i915_request_add(rq);
+               contexts[id] = ce;
        }
 
        for (page = 0; page < num_pages; page++) {
@@ -165,8 +167,21 @@ __igt_reset_stolen(struct intel_gt *gt,
                err = -EINVAL;
        }
 
+       err = intel_gt_wait_for_idle(gt, HZ);
+       if (err < 0) {
+               pr_err("%s failed to wait for gt idle: %d\n", msg, err);
+               goto err_spin;
+       }
+
+       err = 0;
+
 err_spin:
        igt_spinner_fini(&spin);
+       for (id = 0; id < I915_NUM_ENGINES; id++) {
+               if (!contexts[id])
+                       continue;
+               intel_context_put(contexts[id]);
+       }
 
 err_lock:
        intel_runtime_pm_put(gt->uncore->rpm, wakeref);
-- 
2.25.1