[PATCH 09/16] drm/i915: Check for scratch page scribbling
Chris Wilson
chris at chris-wilson.co.uk
Fri Feb 12 13:27:58 UTC 2021
Periodically check, for example when idling and upon closing user
contexts, whether or not some client has written into unallocated PTE in
their ppGTT.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
.../drm/i915/gem/selftests/i915_gem_context.c | 24 +++++++---
.../drm/i915/gem/selftests/i915_gem_mman.c | 32 ++++++++++++-
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 31 +------------
drivers/gpu/drm/i915/gt/intel_gt_pm.c | 10 +++++
drivers/gpu/drm/i915/gt/intel_gtt.c | 45 +++++++++++++++++++
drivers/gpu/drm/i915/gt/intel_gtt.h | 1 +
drivers/gpu/drm/i915/i915_scheduler.c | 33 +-------------
drivers/gpu/drm/i915/i915_utils.c | 29 ++++++++++++
drivers/gpu/drm/i915/i915_utils.h | 3 ++
9 files changed, 141 insertions(+), 67 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index 39fc548d927a..302fa125127f 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -1743,7 +1743,7 @@ static int read_from_scratch(struct i915_gem_context *ctx,
return err;
}
-static int check_scratch_page(struct i915_gem_context *ctx, u32 *out)
+static int check_ctx_scratch(struct i915_gem_context *ctx, u32 *out)
{
struct i915_address_space *vm;
struct page *page;
@@ -1776,6 +1776,17 @@ static int check_scratch_page(struct i915_gem_context *ctx, u32 *out)
return err;
}
+static void reset_ctx_scratch(struct i915_gem_context *ctx, u32 value)
+{
+ struct i915_address_space *vm = ctx_vm(ctx);
+ struct page *page = __px_page(vm->scratch[0]);
+ u32 *vaddr;
+
+ vaddr = kmap(page);
+ memset32(vaddr, value, PAGE_SIZE / sizeof(value));
+ kunmap(page);
+}
+
static int igt_vm_isolation(void *arg)
{
struct drm_i915_private *i915 = arg;
@@ -1822,11 +1833,11 @@ static int igt_vm_isolation(void *arg)
goto out_file;
/* Read the initial state of the scratch page */
- err = check_scratch_page(ctx_a, &expected);
+ err = check_ctx_scratch(ctx_a, &expected);
if (err)
goto out_file;
- err = check_scratch_page(ctx_b, &expected);
+ err = check_ctx_scratch(ctx_b, &expected);
if (err)
goto out_file;
@@ -1861,7 +1872,7 @@ static int igt_vm_isolation(void *arg)
err = read_from_scratch(ctx_b, engine,
offset, &value);
if (err)
- goto out_file;
+ goto out_scratch;
if (value != expected) {
pr_err("%s: Read %08x from scratch (offset 0x%08x_%08x), after %lu reads!\n",
@@ -1870,7 +1881,7 @@ static int igt_vm_isolation(void *arg)
lower_32_bits(offset),
this);
err = -EINVAL;
- goto out_file;
+ goto out_scratch;
}
this++;
@@ -1881,6 +1892,9 @@ static int igt_vm_isolation(void *arg)
pr_info("Checked %lu scratch offsets across %lu engines\n",
count, num_engines);
+out_scratch:
+ /* As we deliberately write into scratch, cover up our tracks */
+ reset_ctx_scratch(ctx_a, expected);
out_file:
if (igt_live_test_end(&t))
err = -EIO;
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index e384ff103bbf..7d2127e1abc2 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -155,6 +155,18 @@ static int check_partial_mapping(struct drm_i915_gem_object *obj,
drm_clflush_virt_range(cpu, sizeof(*cpu));
kunmap(p);
+ if (check_scratch_page(vma->vm)) {
+ pr_err("Partial view for %lu [%u] (offset=%llu, size=%u [%llu, row size %u], fence=%d, tiling=%d, stride=%d) overwrote scratch\n",
+ page, n,
+ view.partial.offset,
+ view.partial.size,
+ vma->size >> PAGE_SHIFT,
+ tile->tiling ? tile_row_pages(obj) : 0,
+ vma->fence ? vma->fence->id : -1,
+ tile->tiling, tile->stride);
+ err = -EIO;
+ }
+
out:
__i915_vma_put(vma);
return err;
@@ -250,6 +262,9 @@ static int check_partial_mappings(struct drm_i915_gem_object *obj,
return -EINTR;
}
+ if (check_scratch_page(&to_i915(obj->base.dev)->ggtt.vm))
+ return -EIO;
+
return 0;
}
@@ -399,7 +414,11 @@ static int igt_partial_tiling(void *arg)
}
}
-next_tiling: ;
+next_tiling:
+ if (check_scratch_page(&i915->ggtt.vm)) {
+ err = -EIO;
+ break;
+ }
}
out_unlock:
@@ -496,6 +515,8 @@ static int igt_smoke_tiling(void *arg)
} while (!__igt_timeout(end, NULL));
pr_info("%s: Completed %lu trials\n", __func__, count);
+ if (check_scratch_page(&i915->ggtt.vm))
+ err = -EIO;
intel_runtime_pm_put(&i915->runtime_pm, wakeref);
i915_gem_object_unpin_pages(obj);
@@ -703,6 +724,8 @@ static int igt_mmap_offset_exhaustion(void *arg)
}
}
+ if (check_scratch_page(&i915->ggtt.vm))
+ err = -EIO;
out:
mmap_offset_lock(i915);
out_park:
@@ -904,6 +927,9 @@ static int __igt_mmap(struct drm_i915_private *i915,
err = wc_check(obj);
if (err == -ENXIO)
err = gtt_check(obj);
+
+ if (check_scratch_page(&i915->ggtt.vm))
+ err = -EIO;
out_unmap:
vm_munmap(addr, obj->base.size);
return err;
@@ -1175,6 +1201,8 @@ static int __igt_mmap_gpu(struct drm_i915_private *i915,
goto out_unmap;
}
+ if (check_scratch_page(&i915->ggtt.vm))
+ err = -EIO;
out_unmap:
vm_munmap(addr, obj->base.size);
return err;
@@ -1316,6 +1344,8 @@ static int __igt_mmap_revoke(struct drm_i915_private *i915,
goto out_unmap;
}
+ if (check_scratch_page(&i915->ggtt.vm))
+ err = -EIO;
out_unmap:
vm_munmap(addr, obj->base.size);
return err;
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 577ebd4a324f..8443794df3ee 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1265,35 +1265,6 @@ bool intel_engine_can_store_dword(struct intel_engine_cs *engine)
}
}
-static void hexdump(struct drm_printer *m, const void *buf, size_t len)
-{
- const size_t rowsize = 8 * sizeof(u32);
- const void *prev = NULL;
- bool skip = false;
- size_t pos;
-
- for (pos = 0; pos < len; pos += rowsize) {
- char line[128];
-
- if (prev && !memcmp(prev, buf + pos, rowsize)) {
- if (!skip) {
- drm_printf(m, "*\n");
- skip = true;
- }
- continue;
- }
-
- WARN_ON_ONCE(hex_dump_to_buffer(buf + pos, len - pos,
- rowsize, sizeof(u32),
- line, sizeof(line),
- false) >= sizeof(line));
- drm_printf(m, "[%04zx] %s\n", pos, line);
-
- prev = buf + pos;
- skip = false;
- }
-}
-
static void intel_engine_print_registers(struct intel_engine_cs *engine,
struct drm_printer *m)
{
@@ -1450,7 +1421,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
}
drm_printf(m, "HWSP:\n");
- hexdump(m, engine->status_page.addr, PAGE_SIZE);
+ i915_hexdump(m, engine->status_page.addr, PAGE_SIZE);
drm_printf(m, "Idle? %s\n", yesno(intel_engine_is_idle(engine)));
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index 24f2cc0b1ca0..e9134f32b84f 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -11,6 +11,7 @@
#include "intel_context.h"
#include "intel_engine_pm.h"
#include "intel_gt.h"
+#include "intel_gtt.h"
#include "intel_gt_clock_utils.h"
#include "intel_gt_pm.h"
#include "intel_gt_requests.h"
@@ -100,6 +101,9 @@ static int __gt_park(struct intel_wakeref *wf)
runtime_end(gt);
intel_gt_park_requests(gt);
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ check_scratch_page(gt->vm);
+
i915_vma_parked(gt);
i915_pmu_gt_parked(i915);
intel_rps_park(>->rps);
@@ -215,6 +219,8 @@ int intel_gt_resume(struct intel_gt *gt)
return err;
GT_TRACE(gt, "\n");
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ check_scratch_page(gt->vm);
/*
* After resume, we may need to poke into the pinned kernel
@@ -301,6 +307,8 @@ void intel_gt_suspend_prepare(struct intel_gt *gt)
/* Flush all the contexts and internal state before turning off GGTT */
gt_sanitize(gt, false);
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ check_scratch_page(gt->vm);
}
static suspend_state_t pm_suspend_target(void)
@@ -344,6 +352,8 @@ void intel_gt_suspend_late(struct intel_gt *gt)
}
gt_sanitize(gt, false); /* Be paranoid, remove all residual GPU state */
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ check_scratch_page(gt->vm);
GT_TRACE(gt, "\n");
}
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index d34770ae4c9a..1357fd440f77 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -158,10 +158,52 @@ static void poison_scratch_page(struct drm_i915_gem_object *scratch)
vaddr = kmap(page);
memset(vaddr, val, PAGE_SIZE);
+ set_page_dirty(page); /* keep the poisoned contents */
kunmap(page);
}
}
+bool check_scratch_page(const struct i915_address_space *vm)
+{
+ struct drm_i915_gem_object *scratch;
+ struct sgt_iter sgt;
+ struct page *page;
+ void *vaddr;
+ u8 val;
+
+ scratch = vm->scratch[0];
+ if (!scratch || !i915_gem_object_has_struct_page(scratch))
+ return false;
+
+ val = 0;
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ val = POISON_FREE;
+
+ for_each_sgt_page(page, sgt, scratch->mm.pages) {
+ vaddr = kmap(page);
+ drm_clflush_virt_range(vaddr, PAGE_SIZE);
+ if (memchr_inv(vaddr, val, PAGE_SIZE)) {
+ struct drm_printer p = drm_err_printer(__func__);
+
+ drm_err(&vm->i915->drm,
+ "%s scratch page overwitten, detected by %pS!\n",
+ i915_is_ggtt(vm) ? "Global" : "Per-process",
+ (void *)_RET_IP_);
+ i915_hexdump(&p, vaddr, PAGE_SIZE);
+ vaddr = NULL;
+ }
+ kunmap(page);
+
+ /* Restore the poison, so fresh errors will be detected */
+ if (!vaddr) {
+ poison_scratch_page(scratch);
+ return true;
+ }
+ }
+
+ return false;
+}
+
int setup_scratch_page(struct i915_address_space *vm)
{
unsigned long size;
@@ -229,6 +271,9 @@ void free_scratch(struct i915_address_space *vm)
{
int i;
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ check_scratch_page(vm);
+
for (i = 0; i <= vm->top; i++)
i915_gem_object_put(vm->scratch[i]);
}
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index 24b5808df16d..12f7261e4c89 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -519,6 +519,7 @@ fill_page_dma(struct drm_i915_gem_object *p, const u64 val, unsigned int count);
} while (0)
int setup_scratch_page(struct i915_address_space *vm);
+bool check_scratch_page(const struct i915_address_space *vm);
void free_scratch(struct i915_address_space *vm);
struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm, int sz);
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index a8fb787278e6..7241f85c9967 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -1095,35 +1095,6 @@ void i915_request_show_with_schedule(struct drm_printer *m,
rcu_read_unlock();
}
-static void hexdump(struct drm_printer *m, const void *buf, size_t len)
-{
- const size_t rowsize = 8 * sizeof(u32);
- const void *prev = NULL;
- bool skip = false;
- size_t pos;
-
- for (pos = 0; pos < len; pos += rowsize) {
- char line[128];
-
- if (prev && !memcmp(prev, buf + pos, rowsize)) {
- if (!skip) {
- drm_printf(m, "*\n");
- skip = true;
- }
- continue;
- }
-
- WARN_ON_ONCE(hex_dump_to_buffer(buf + pos, len - pos,
- rowsize, sizeof(u32),
- line, sizeof(line),
- false) >= sizeof(line));
- drm_printf(m, "[%04zx] %s\n", pos, line);
-
- prev = buf + pos;
- skip = false;
- }
-}
-
static void
print_request_ring(struct drm_printer *m, const struct i915_request *rq)
{
@@ -1153,7 +1124,7 @@ print_request_ring(struct drm_printer *m, const struct i915_request *rq)
}
memcpy(ring + len, vaddr + head, size - len);
- hexdump(m, ring, size);
+ i915_hexdump(m, ring, size);
kfree(ring);
}
}
@@ -1195,7 +1166,7 @@ void i915_sched_show(struct drm_printer *m,
if (rq->context->lrc_reg_state) {
drm_printf(m, "Logical Ring Context:\n");
- hexdump(m, rq->context->lrc_reg_state, PAGE_SIZE);
+ i915_hexdump(m, rq->context->lrc_reg_state, PAGE_SIZE);
}
}
diff --git a/drivers/gpu/drm/i915/i915_utils.c b/drivers/gpu/drm/i915/i915_utils.c
index 894de60833ec..432ad0926586 100644
--- a/drivers/gpu/drm/i915/i915_utils.c
+++ b/drivers/gpu/drm/i915/i915_utils.c
@@ -49,6 +49,35 @@ __i915_printk(struct drm_i915_private *dev_priv, const char *level,
}
}
+void i915_hexdump(struct drm_printer *m, const void *buf, size_t len)
+{
+ const size_t rowsize = 8 * sizeof(u32);
+ const void *prev = NULL;
+ bool skip = false;
+ size_t pos;
+
+ for (pos = 0; pos < len; pos += rowsize) {
+ char line[128];
+
+ if (prev && !memcmp(prev, buf + pos, rowsize)) {
+ if (!skip) {
+ drm_printf(m, "*\n");
+ skip = true;
+ }
+ continue;
+ }
+
+ WARN_ON_ONCE(hex_dump_to_buffer(buf + pos, len - pos,
+ rowsize, sizeof(u32),
+ line, sizeof(line),
+ false) >= sizeof(line));
+ drm_printf(m, "[%04zx] %s\n", pos, line);
+
+ prev = buf + pos;
+ skip = false;
+ }
+}
+
void add_taint_for_CI(struct drm_i915_private *i915, unsigned int taint)
{
__i915_printk(i915, KERN_NOTICE, "CI tainted:%#x by %pS\n",
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 4618fe8aacb5..c82461d6ae71 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -32,6 +32,7 @@
#include <linux/workqueue.h>
struct drm_i915_private;
+struct drm_printer;
struct timer_list;
#define FDO_BUG_URL "https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs"
@@ -82,6 +83,8 @@ bool i915_error_injected(void);
__i915_printk(i915, i915_error_injected() ? KERN_DEBUG : KERN_ERR, \
fmt, ##__VA_ARGS__)
+void i915_hexdump(struct drm_printer *m, const void *buf, size_t len);
+
#if defined(GCC_VERSION) && GCC_VERSION >= 70000
#define add_overflows_t(T, A, B) \
__builtin_add_overflow_p((A), (B), (T)0)
--
2.20.1
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