[Intel-gfx] [RFC 15/22] drm/i915: Reject commands that would store to global HWS page

[bradley.d.volkin at intel.com]

From: Brad Volkin <bradley.d.volkin at intel.com>

PIPE_CONTROL and MI_FLUSH_DW have bits that would write to the
hardware status page. There are no users of this today and it
seems unsafe.

Signed-off-by: Brad Volkin <bradley.d.volkin at intel.com>
---
 drivers/gpu/drm/i915/i915_cmd_parser.c | 30 ++++++++++++++++++++++++++----
 drivers/gpu/drm/i915/i915_reg.h        |  1 +
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index 7b30a03..f32dc69 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -131,7 +131,8 @@ static const struct drm_i915_cmd_descriptor render_cmds[] = {
 	      },
 	      {
 			.offset = 1,
-			.mask = PIPE_CONTROL_GLOBAL_GTT_IVB,
+		        .mask = (PIPE_CONTROL_GLOBAL_GTT_IVB |
+				 PIPE_CONTROL_STORE_DATA_INDEX),
 			.expected = 0,
 			.condition_offset = 1,
 			.condition_mask = PIPE_CONTROL_POST_SYNC_OP_MASK
@@ -167,8 +168,15 @@ static const struct drm_i915_cmd_descriptor video_cmds[] = {
 			.expected = 0,
 			.condition_offset = 0,
 			.condition_mask = MI_FLUSH_DW_OP_MASK
+	      },
+	      {
+			.offset = 0,
+			.mask = MI_FLUSH_DW_STORE_INDEX,
+			.expected = 0,
+			.condition_offset = 0,
+			.condition_mask = MI_FLUSH_DW_OP_MASK
 	      }},
-	      .bits_count = 2					       ),
+	      .bits_count = 3					       ),
 	CMD(  MI_CONDITIONAL_BATCH_BUFFER_END,  SMI,   !F,  0xFF,   B,
 	      .bits = {{
 			.offset = 0,
@@ -192,8 +200,15 @@ static const struct drm_i915_cmd_descriptor vecs_cmds[] = {
 			.expected = 0,
 			.condition_offset = 0,
 			.condition_mask = MI_FLUSH_DW_OP_MASK
+	      },
+	      {
+			.offset = 0,
+			.mask = MI_FLUSH_DW_STORE_INDEX,
+			.expected = 0,
+			.condition_offset = 0,
+			.condition_mask = MI_FLUSH_DW_OP_MASK
 	      }},
-	      .bits_count = 2					       ),
+	      .bits_count = 3					       ),
 	CMD(  MI_CONDITIONAL_BATCH_BUFFER_END,  SMI,   !F,  0xFF,   B,
 	      .bits = {{
 			.offset = 0,
@@ -217,8 +232,15 @@ static const struct drm_i915_cmd_descriptor blt_cmds[] = {
 			.expected = 0,
 			.condition_offset = 0,
 			.condition_mask = MI_FLUSH_DW_OP_MASK
+	      },
+	      {
+			.offset = 0,
+			.mask = MI_FLUSH_DW_STORE_INDEX,
+			.expected = 0,
+			.condition_offset = 0,
+			.condition_mask = MI_FLUSH_DW_OP_MASK
 	      }},
-	      .bits_count = 2					       ),
+	      .bits_count = 3					       ),
 	CMD(  COLOR_BLT,                        S2D,   !F,  0x3F,   S  ),
 	CMD(  SRC_COPY_BLT,                     S2D,   !F,  0x3F,   S  ),
 };
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3f64d41..919d1a6 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -323,6 +323,7 @@
 #define GFX_OP_PIPE_CONTROL(len)	((0x3<<29)|(0x3<<27)|(0x2<<24)|(len-2))
 #define   PIPE_CONTROL_GLOBAL_GTT_IVB			(1<<24) /* gen7+ */
 #define   PIPE_CONTROL_MMIO_WRITE			(1<<23)
+#define   PIPE_CONTROL_STORE_DATA_INDEX			(1<<21)
 #define   PIPE_CONTROL_CS_STALL				(1<<20)
 #define   PIPE_CONTROL_TLB_INVALIDATE			(1<<18)
 #define   PIPE_CONTROL_QW_WRITE				(1<<14)
-- 
1.8.4.4