drm/i915/execlists: Verify context register state before execution

Check that the context's ring register state still matches our
expectations prior to execution.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191102125739.24626-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 51aef2a..f2b31c9 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -990,6 +990,58 @@ static void intel_engine_context_out(struct intel_engine_cs *engine)
        write_sequnlock_irqrestore(&engine->stats.lock, flags);
 }
 
+static int lrc_ring_mi_mode(const struct intel_engine_cs *engine)
+{
+       if (INTEL_GEN(engine->i915) >= 12)
+               return 0x60;
+       else if (INTEL_GEN(engine->i915) >= 9)
+               return 0x54;
+       else if (engine->class == RENDER_CLASS)
+               return 0x58;
+       else
+               return -1;
+}
+
+static void
+execlists_check_context(const struct intel_context *ce,
+                       const struct intel_engine_cs *engine)
+{
+       const struct intel_ring *ring = ce->ring;
+       u32 *regs = ce->lrc_reg_state;
+       bool valid = true;
+       int x;
+
+       if (regs[CTX_RING_START] != i915_ggtt_offset(ring->vma)) {
+               pr_err("%s: context submitted with incorrect RING_START [%08x], expected %08x\n",
+                      engine->name,
+                      regs[CTX_RING_START],
+                      i915_ggtt_offset(ring->vma));
+               regs[CTX_RING_START] = i915_ggtt_offset(ring->vma);
+               valid = false;
+       }
+
+       if ((regs[CTX_RING_CTL] & ~(RING_WAIT | RING_WAIT_SEMAPHORE)) !=
+           (RING_CTL_SIZE(ring->size) | RING_VALID)) {
+               pr_err("%s: context submitted with incorrect RING_CTL [%08x], expected %08x\n",
+                      engine->name,
+                      regs[CTX_RING_CTL],
+                      (u32)(RING_CTL_SIZE(ring->size) | RING_VALID));
+               regs[CTX_RING_CTL] = RING_CTL_SIZE(ring->size) | RING_VALID;
+               valid = false;
+       }
+
+       x = lrc_ring_mi_mode(engine);
+       if (x != -1 && regs[x + 1] & (regs[x + 1] >> 16) & STOP_RING) {
+               pr_err("%s: context submitted with STOP_RING [%08x] in RING_MI_MODE\n",
+                      engine->name, regs[x + 1]);
+               regs[x + 1] &= ~STOP_RING;
+               regs[x + 1] |= STOP_RING << 16;
+               valid = false;
+       }
+
+       WARN_ONCE(!valid, "Invalid lrc state found before submission\n");
+}
+
 static inline struct intel_engine_cs *
 __execlists_schedule_in(struct i915_request *rq)
 {
@@ -998,6 +1050,9 @@ __execlists_schedule_in(struct i915_request *rq)
 
        intel_context_get(ce);
 
+       if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+               execlists_check_context(ce, rq->engine);
+
        if (ce->tag) {
                /* Use a fixed tag for OA and friends */
                ce->lrc_desc |= (u64)ce->tag << 32;
@@ -2353,7 +2408,7 @@ __execlists_update_reg_state(const struct intel_context *ce,
        GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->head));
        GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->tail));
 
-       regs[CTX_RING_BUFFER_START] = i915_ggtt_offset(ring->vma);
+       regs[CTX_RING_START] = i915_ggtt_offset(ring->vma);
        regs[CTX_RING_HEAD] = ring->head;
        regs[CTX_RING_TAIL] = ring->tail;
 
@@ -2940,18 +2995,6 @@ static void reset_csb_pointers(struct intel_engine_cs *engine)
                               &execlists->csb_status[reset_value]);
 }
 
-static int lrc_ring_mi_mode(const struct intel_engine_cs *engine)
-{
-       if (INTEL_GEN(engine->i915) >= 12)
-               return 0x60;
-       else if (INTEL_GEN(engine->i915) >= 9)
-               return 0x54;
-       else if (engine->class == RENDER_CLASS)
-               return 0x58;
-       else
-               return -1;
-}
-
 static void __execlists_reset_reg_state(const struct intel_context *ce,
                                        const struct intel_engine_cs *engine)
 {
@@ -3885,7 +3928,7 @@ static void init_common_reg_state(u32 * const regs,
                        _MASKED_BIT_DISABLE(CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT |
                                            CTX_CTRL_RS_CTX_ENABLE);
 
-       regs[CTX_RING_BUFFER_CONTROL] = RING_CTL_SIZE(ring->size) | RING_VALID;
+       regs[CTX_RING_CTL] = RING_CTL_SIZE(ring->size) | RING_VALID;
        regs[CTX_BB_STATE] = RING_BB_PPGTT;
 }
 

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc_reg.h b/drivers/gpu/drm/i915/gt/intel_lrc_reg.h
index 06ab027..08a3be6 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_lrc_reg.h
+++ b/drivers/gpu/drm/i915/gt/intel_lrc_reg.h
@@ -13,8 +13,8 @@
 #define CTX_CONTEXT_CONTROL            (0x02 + 1)
 #define CTX_RING_HEAD                  (0x04 + 1)
 #define CTX_RING_TAIL                  (0x06 + 1)
-#define CTX_RING_BUFFER_START          (0x08 + 1)
-#define CTX_RING_BUFFER_CONTROL                (0x0a + 1)
+#define CTX_RING_START                 (0x08 + 1)
+#define CTX_RING_CTL                   (0x0a + 1)
 #define CTX_BB_STATE                   (0x10 + 1)
 #define CTX_BB_PER_CTX_PTR             (0x18 + 1)
 #define CTX_PDP3_UDW                   (0x24 + 1)

diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index eb71ac2..d1ed3c0 100644 (file)
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -3207,12 +3207,12 @@ static int live_lrc_fixed(void *arg)
                } tbl[] = {
                        {
                                i915_mmio_reg_offset(RING_START(engine->mmio_base)),
-                               CTX_RING_BUFFER_START - 1,
+                               CTX_RING_START - 1,
                                "RING_START"
                        },
                        {
                                i915_mmio_reg_offset(RING_CTL(engine->mmio_base)),
-                               CTX_RING_BUFFER_CONTROL - 1,
+                               CTX_RING_CTL - 1,
                                "RING_CTL"
                        },
                        {
@@ -3231,7 +3231,7 @@ static int live_lrc_fixed(void *arg)
                                "RING_MI_MODE"
                        },
                        {
-                               engine->mmio_base + 0x110,
+                               i915_mmio_reg_offset(RING_BBSTATE(engine->mmio_base)),
                                CTX_BB_STATE - 1,
                                "BB_STATE"
                        },