Commit 6e7a21e7 authored by Chris Wilson's avatar Chris Wilson

drm/i915/selftests: Exercise intel_timeline_read_hwsp()

intel_timeline_read_hwsp() is used to support semaphore waits between
engines, that may themselves be deferred for arbitrary periods -- that
is the read of the target request's HWSP is at an indeterminant point in
the future. To support this, we need to prevent overwriting a HWSP that
is being watched across a seqno wrap (otherwise the next request will
write its value into the old HWSP preventing the watcher from making
progress, ad infinitum.) To simulate the observer across a wrap, let's
create a request that reads from the HWSP and dispatch it at different
points around a wrap to see if the value is lost.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201021220411.5777-2-chris@chris-wilson.co.uk
parent c10f6019
......@@ -17,8 +17,9 @@
#include "../selftests/i915_random.h"
#include "../i915_selftest.h"
#include "../selftests/igt_flush_test.h"
#include "../selftests/mock_gem_device.h"
#include "selftests/igt_flush_test.h"
#include "selftests/lib_sw_fence.h"
#include "selftests/mock_gem_device.h"
#include "selftests/mock_timeline.h"
static struct page *hwsp_page(struct intel_timeline *tl)
......@@ -755,6 +756,378 @@ static int live_hwsp_wrap(void *arg)
return err;
}
static int emit_read_hwsp(struct i915_request *rq,
u32 seqno, u32 hwsp,
u32 *addr)
{
const u32 gpr = i915_mmio_reg_offset(GEN8_RING_CS_GPR(rq->engine->mmio_base, 0));
u32 *cs;
cs = intel_ring_begin(rq, 12);
if (IS_ERR(cs))
return PTR_ERR(cs);
*cs++ = MI_STORE_DWORD_IMM_GEN4 | MI_USE_GGTT;
*cs++ = *addr;
*cs++ = 0;
*cs++ = seqno;
*addr += 4;
*cs++ = MI_LOAD_REGISTER_MEM_GEN8 | MI_USE_GGTT;
*cs++ = gpr;
*cs++ = hwsp;
*cs++ = 0;
*cs++ = MI_STORE_REGISTER_MEM_GEN8 | MI_USE_GGTT;
*cs++ = gpr;
*cs++ = *addr;
*cs++ = 0;
*addr += 4;
intel_ring_advance(rq, cs);
return 0;
}
struct hwsp_watcher {
struct i915_vma *vma;
struct i915_request *rq;
u32 addr;
u32 *map;
};
static bool cmp_lt(u32 a, u32 b)
{
return a < b;
}
static bool cmp_gte(u32 a, u32 b)
{
return a >= b;
}
static int setup_watcher(struct hwsp_watcher *w, struct intel_gt *gt)
{
struct drm_i915_gem_object *obj;
struct i915_vma *vma;
obj = i915_gem_object_create_internal(gt->i915, SZ_2M);
if (IS_ERR(obj))
return PTR_ERR(obj);
w->map = i915_gem_object_pin_map(obj, I915_MAP_WB);
if (IS_ERR(w->map)) {
i915_gem_object_put(obj);
return PTR_ERR(w->map);
}
vma = i915_gem_object_ggtt_pin_ww(obj, NULL, NULL, 0, 0, 0);
if (IS_ERR(vma)) {
i915_gem_object_put(obj);
return PTR_ERR(vma);
}
w->vma = vma;
w->addr = i915_ggtt_offset(vma);
return 0;
}
static int create_watcher(struct hwsp_watcher *w,
struct intel_engine_cs *engine,
int ringsz)
{
struct intel_context *ce;
struct intel_timeline *tl;
ce = intel_context_create(engine);
if (IS_ERR(ce))
return PTR_ERR(ce);
ce->ring = __intel_context_ring_size(ringsz);
w->rq = intel_context_create_request(ce);
intel_context_put(ce);
if (IS_ERR(w->rq))
return PTR_ERR(w->rq);
w->addr = i915_ggtt_offset(w->vma);
tl = w->rq->context->timeline;
/* some light mutex juggling required; think co-routines */
lockdep_unpin_lock(&tl->mutex, w->rq->cookie);
mutex_unlock(&tl->mutex);
return 0;
}
static int check_watcher(struct hwsp_watcher *w, const char *name,
bool (*op)(u32 hwsp, u32 seqno))
{
struct i915_request *rq = fetch_and_zero(&w->rq);
struct intel_timeline *tl = rq->context->timeline;
u32 offset, end;
int err;
GEM_BUG_ON(w->addr - i915_ggtt_offset(w->vma) > w->vma->size);
i915_request_get(rq);
mutex_lock(&tl->mutex);
rq->cookie = lockdep_pin_lock(&tl->mutex);
i915_request_add(rq);
if (i915_request_wait(rq, 0, HZ) < 0) {
err = -ETIME;
goto out;
}
err = 0;
offset = 0;
end = (w->addr - i915_ggtt_offset(w->vma)) / sizeof(*w->map);
while (offset < end) {
if (!op(w->map[offset + 1], w->map[offset])) {
pr_err("Watcher '%s' found HWSP value %x for seqno %x\n",
name, w->map[offset + 1], w->map[offset]);
err = -EINVAL;
}
offset += 2;
}
out:
i915_request_put(rq);
return err;
}
static void cleanup_watcher(struct hwsp_watcher *w)
{
if (w->rq) {
struct intel_timeline *tl = w->rq->context->timeline;
mutex_lock(&tl->mutex);
w->rq->cookie = lockdep_pin_lock(&tl->mutex);
i915_request_add(w->rq);
}
i915_vma_unpin_and_release(&w->vma, I915_VMA_RELEASE_MAP);
}
static bool retire_requests(struct intel_timeline *tl)
{
struct i915_request *rq, *rn;
mutex_lock(&tl->mutex);
list_for_each_entry_safe(rq, rn, &tl->requests, link)
if (!i915_request_retire(rq))
break;
mutex_unlock(&tl->mutex);
return !i915_active_fence_isset(&tl->last_request);
}
static struct i915_request *wrap_timeline(struct i915_request *rq)
{
struct intel_context *ce = rq->context;
struct intel_timeline *tl = ce->timeline;
u32 seqno = rq->fence.seqno;
while (tl->seqno >= seqno) { /* Cause a wrap */
i915_request_put(rq);
rq = intel_context_create_request(ce);
if (IS_ERR(rq))
return rq;
i915_request_get(rq);
i915_request_add(rq);
}
i915_request_put(rq);
rq = intel_context_create_request(ce);
if (IS_ERR(rq))
return rq;
i915_request_get(rq);
i915_request_add(rq);
return rq;
}
static int live_hwsp_read(void *arg)
{
struct intel_gt *gt = arg;
struct hwsp_watcher watcher[2] = {};
struct intel_engine_cs *engine;
struct intel_timeline *tl;
enum intel_engine_id id;
int err = 0;
int i;
/*
* If we take a reference to the HWSP for reading on the GPU, that
* read may be arbitrarily delayed (either by foreign fence or
* priority saturation) and a wrap can happen within 30 minutes.
* When the GPU read is finally submitted it should be correct,
* even across multiple wraps.
*/
if (INTEL_GEN(gt->i915) < 8) /* CS convenience [SRM/LRM] */
return 0;
tl = intel_timeline_create(gt);
if (IS_ERR(tl))
return PTR_ERR(tl);
if (!tl->hwsp_cacheline)
goto out_free;
for (i = 0; i < ARRAY_SIZE(watcher); i++) {
err = setup_watcher(&watcher[i], gt);
if (err)
goto out;
}
for_each_engine(engine, gt, id) {
struct intel_context *ce;
unsigned long count = 0;
IGT_TIMEOUT(end_time);
/* Create a request we can use for remote reading of the HWSP */
err = create_watcher(&watcher[1], engine, SZ_512K);
if (err)
goto out;
do {
struct i915_sw_fence *submit;
struct i915_request *rq;
u32 hwsp;
submit = heap_fence_create(GFP_KERNEL);
if (!submit) {
err = -ENOMEM;
goto out;
}
err = create_watcher(&watcher[0], engine, SZ_4K);
if (err)
goto out;
ce = intel_context_create(engine);
if (IS_ERR(ce)) {
err = PTR_ERR(ce);
goto out;
}
/* Skip to the end, saving 30 minutes of nops */
tl->seqno = -10u + 2 * (count & 3);
WRITE_ONCE(*(u32 *)tl->hwsp_seqno, tl->seqno);
ce->timeline = intel_timeline_get(tl);
rq = intel_context_create_request(ce);
if (IS_ERR(rq)) {
err = PTR_ERR(rq);
intel_context_put(ce);
goto out;
}
err = i915_sw_fence_await_dma_fence(&rq->submit,
&watcher[0].rq->fence, 0,
GFP_KERNEL);
if (err < 0) {
i915_request_add(rq);
intel_context_put(ce);
goto out;
}
mutex_lock(&watcher[0].rq->context->timeline->mutex);
err = intel_timeline_read_hwsp(rq, watcher[0].rq, &hwsp);
if (err == 0)
err = emit_read_hwsp(watcher[0].rq, /* before */
rq->fence.seqno, hwsp,
&watcher[0].addr);
mutex_unlock(&watcher[0].rq->context->timeline->mutex);
if (err) {
i915_request_add(rq);
intel_context_put(ce);
goto out;
}
mutex_lock(&watcher[1].rq->context->timeline->mutex);
err = intel_timeline_read_hwsp(rq, watcher[1].rq, &hwsp);
if (err == 0)
err = emit_read_hwsp(watcher[1].rq, /* after */
rq->fence.seqno, hwsp,
&watcher[1].addr);
mutex_unlock(&watcher[1].rq->context->timeline->mutex);
if (err) {
i915_request_add(rq);
intel_context_put(ce);
goto out;
}
i915_request_get(rq);
i915_request_add(rq);
rq = wrap_timeline(rq);
intel_context_put(ce);
if (IS_ERR(rq)) {
err = PTR_ERR(rq);
goto out;
}
err = i915_sw_fence_await_dma_fence(&watcher[1].rq->submit,
&rq->fence, 0,
GFP_KERNEL);
if (err < 0) {
i915_request_put(rq);
goto out;
}
err = check_watcher(&watcher[0], "before", cmp_lt);
i915_sw_fence_commit(submit);
heap_fence_put(submit);
if (err) {
i915_request_put(rq);
goto out;
}
count++;
if (8 * watcher[1].rq->ring->emit >
3 * watcher[1].rq->ring->size) {
i915_request_put(rq);
break;
}
/* Flush the timeline before manually wrapping again */
if (i915_request_wait(rq,
I915_WAIT_INTERRUPTIBLE,
HZ) < 0) {
err = -ETIME;
i915_request_put(rq);
goto out;
}
retire_requests(tl);
i915_request_put(rq);
} while (!__igt_timeout(end_time, NULL));
WRITE_ONCE(*(u32 *)tl->hwsp_seqno, 0xdeadbeef);
pr_info("%s: simulated %lu wraps\n", engine->name, count);
err = check_watcher(&watcher[1], "after", cmp_gte);
if (err)
goto out;
}
out:
for (i = 0; i < ARRAY_SIZE(watcher); i++)
cleanup_watcher(&watcher[i]);
if (igt_flush_test(gt->i915))
err = -EIO;
out_free:
intel_timeline_put(tl);
return err;
}
static int live_hwsp_rollover_kernel(void *arg)
{
struct intel_gt *gt = arg;
......@@ -998,6 +1371,7 @@ int intel_timeline_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_hwsp_engine),
SUBTEST(live_hwsp_alternate),
SUBTEST(live_hwsp_wrap),
SUBTEST(live_hwsp_read),
SUBTEST(live_hwsp_rollover_kernel),
SUBTEST(live_hwsp_rollover_user),
};
......
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