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drm/i915/selftests: Check the context size 

Add a redzone to our context image and check the HW does not write into
after a context save, to verify that we have the correct context size.
(This does vary with feature bits, so test with a live setup that should
match how we run userspace.)

v2: Check the redzone on every context unpin
v3: Use a kernel context to prevent loading garbage for ringbuffer
submission

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190817073711.5897-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2019-08-17 08:37:11 +01:00
parent eb7c022ddc
commit 9559c87513
2 changed files with 175 additions and 0 deletions
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34
drivers/gpu/drm/i915/gt/intel_lrc.c
View File

@ -1617,8 +1617,38 @@ static void execlists_context_destroy(struct kref *kref)
intel_context_free(ce);
}
static void
set_redzone(void *vaddr, const struct intel_engine_cs *engine)
{
if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
return;
vaddr += LRC_HEADER_PAGES * PAGE_SIZE;
vaddr += engine->context_size;
memset(vaddr, POISON_INUSE, I915_GTT_PAGE_SIZE);
}
static void
check_redzone(const void *vaddr, const struct intel_engine_cs *engine)
{
if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
return;
vaddr += LRC_HEADER_PAGES * PAGE_SIZE;
vaddr += engine->context_size;
if (memchr_inv(vaddr, POISON_INUSE, I915_GTT_PAGE_SIZE))
dev_err_once(engine->i915->drm.dev,
"%s context redzone overwritten!\n",
engine->name);
}
static void execlists_context_unpin(struct intel_context *ce)
{
check_redzone((void *)ce->lrc_reg_state - LRC_STATE_PN * PAGE_SIZE,
ce->engine);
i915_gem_context_unpin_hw_id(ce->gem_context);
i915_gem_object_unpin_map(ce->state->obj);
intel_ring_reset(ce->ring, ce->ring->tail);
@ -3157,6 +3187,8 @@ populate_lr_context(struct intel_context *ce,
return ret;
}
set_redzone(vaddr, engine);
if (engine->default_state) {
/*
* We only want to copy over the template context state;
@ -3211,6 +3243,8 @@ static int __execlists_context_alloc(struct intel_context *ce,
* for our own use and for sharing with the GuC.
*/
context_size += LRC_HEADER_PAGES * PAGE_SIZE;
if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
context_size += I915_GTT_PAGE_SIZE; /* for redzone */
ctx_obj = i915_gem_object_create_shmem(engine->i915, context_size);
if (IS_ERR(ctx_obj))

141
drivers/gpu/drm/i915/gt/selftest_context.c
View File

@ -5,6 +5,7 @@
*/
#include "i915_selftest.h"
#include "intel_engine_pm.h"
#include "intel_gt.h"
#include "gem/selftests/mock_context.h"
@ -64,6 +65,145 @@ static int context_sync(struct intel_context *ce)
return err;
}
static int __live_context_size(struct intel_engine_cs *engine,
struct i915_gem_context *fixme)
{
struct intel_context *ce;
struct i915_request *rq;
void *vaddr;
int err;
ce = intel_context_create(fixme, engine);
if (IS_ERR(ce))
return PTR_ERR(ce);
err = intel_context_pin(ce);
if (err)
goto err;
vaddr = i915_gem_object_pin_map(ce->state->obj,
i915_coherent_map_type(engine->i915));
if (IS_ERR(vaddr)) {
err = PTR_ERR(vaddr);
intel_context_unpin(ce);
goto err;
}
/*
* Note that execlists also applies a redzone which it checks on
* context unpin when debugging. We are using the same location
* and same poison value so that our checks overlap. Despite the
* redundancy, we want to keep this little selftest so that we
* get coverage of any and all submission backends, and we can
* always extend this test to ensure we trick the HW into a
* compromising position wrt to the various sections that need
* to be written into the context state.
*
* TLDR; this overlaps with the execlists redzone.
*/
if (HAS_EXECLISTS(engine->i915))
vaddr += LRC_HEADER_PAGES * PAGE_SIZE;
vaddr += engine->context_size - I915_GTT_PAGE_SIZE;
memset(vaddr, POISON_INUSE, I915_GTT_PAGE_SIZE);
rq = intel_context_create_request(ce);
intel_context_unpin(ce);
if (IS_ERR(rq)) {
err = PTR_ERR(rq);
goto err_unpin;
}
err = request_sync(rq);
if (err)
goto err_unpin;
/* Force the context switch */
rq = i915_request_create(engine->kernel_context);
if (IS_ERR(rq)) {
err = PTR_ERR(rq);
goto err_unpin;
}
err = request_sync(rq);
if (err)
goto err_unpin;
if (memchr_inv(vaddr, POISON_INUSE, I915_GTT_PAGE_SIZE)) {
pr_err("%s context overwrote trailing red-zone!", engine->name);
err = -EINVAL;
}
err_unpin:
i915_gem_object_unpin_map(ce->state->obj);
err:
intel_context_put(ce);
return err;
}
static int live_context_size(void *arg)
{
struct intel_gt *gt = arg;
struct intel_engine_cs *engine;
struct i915_gem_context *fixme;
enum intel_engine_id id;
int err = 0;
/*
* Check that our context sizes are correct by seeing if the
* HW tries to write past the end of one.
*/
mutex_lock(&gt->i915->drm.struct_mutex);
fixme = kernel_context(gt->i915);
if (IS_ERR(fixme)) {
err = PTR_ERR(fixme);
goto unlock;
}
for_each_engine(engine, gt->i915, id) {
struct {
struct drm_i915_gem_object *state;
void *pinned;
} saved;
if (!engine->context_size)
continue;
intel_engine_pm_get(engine);
/*
* Hide the old default state -- we lie about the context size
* and get confused when the default state is smaller than
* expected. For our do nothing request, inheriting the
* active state is sufficient, we are only checking that we
* don't use more than we planned.
*/
saved.state = fetch_and_zero(&engine->default_state);
saved.pinned = fetch_and_zero(&engine->pinned_default_state);
/* Overlaps with the execlists redzone */
engine->context_size += I915_GTT_PAGE_SIZE;
err = __live_context_size(engine, fixme);
engine->context_size -= I915_GTT_PAGE_SIZE;
engine->pinned_default_state = saved.pinned;
engine->default_state = saved.state;
intel_engine_pm_put(engine);
if (err)
break;
}
kernel_context_close(fixme);
unlock:
mutex_unlock(&gt->i915->drm.struct_mutex);
return err;
}
static int __live_active_context(struct intel_engine_cs *engine,
struct i915_gem_context *fixme)
{
@ -303,6 +443,7 @@ static int live_remote_context(void *arg)
int intel_context_live_selftests(struct drm_i915_private *i915)
{
static const struct i915_subtest tests[] = {
SUBTEST(live_context_size),
SUBTEST(live_active_context),
SUBTEST(live_remote_context),
};