[PATCH V2] drm/i915/gvt: addressed guest GPU hang with HWS index mode

[Xiaolin Zhang]

with the introduce of "switch to use HWS indices rather than address",
guest GPU hang observed when running workloads which will update the
seqno to the real HW HWSP, not vitural GPU HWSP and then cause GPU hang.

this patch is to revoke index mode in PIPE_CTRL and MI_FLUSH_DW and
patch guest GPU HWSP address value to these commands.

Fixes: 54939ea0b("drm/i915: Switch to use HWS indices rather than
addresses")

v2: PIPE_CTRL and MI_FLUSH_DW has different address offset, offset is
also passed for gma address update. <zhenyu>

Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
---
 drivers/gpu/drm/i915/gvt/cmd_parser.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
index b420919279c7..2716fd349ecc 100644
--- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
+++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
@@ -1070,6 +1070,18 @@ static struct cmd_interrupt_event cmd_interrupt_events[] = {
 	},
 };
 
+static int index_mode_to_gma(struct parser_exec_state *s, u32 offset, u32 index)
+{
+	u32 gma;
+	u32 val;
+
+	gma = s->vgpu->hws_pga[s->ring_id] + index;
+	patch_value(s, cmd_ptr(s, offset), gma);
+	val = cmd_val(s, offset - 1) & (~PIPE_CONTROL_STORE_DATA_INDEX);
+	patch_value(s, cmd_ptr(s, offset - 1), val);
+	return 0;
+}
+
 static int cmd_handler_pipe_control(struct parser_exec_state *s)
 {
 	int gmadr_bytes = s->vgpu->gvt->device_info.gmadr_bytes_in_cmd;
@@ -1098,8 +1110,11 @@ static int cmd_handler_pipe_control(struct parser_exec_state *s)
 				/* Store Data Index */
 				if (cmd_val(s, 1) & (1 << 21))
 					index_mode = true;
-				ret |= cmd_address_audit(s, gma, sizeof(u64),
-						index_mode);
+				if (index_mode)
+					ret = index_mode_to_gma(s, 2, gma);
+				else
+					ret |= cmd_address_audit(s, gma,
+						sizeof(u64), index_mode);
 			}
 		}
 	}
@@ -1607,7 +1622,11 @@ static int cmd_handler_mi_flush_dw(struct parser_exec_state *s)
 		/* Store Data Index */
 		if (cmd_val(s, 0) & (1 << 21))
 			index_mode = true;
-		ret = cmd_address_audit(s, gma, sizeof(u64), index_mode);
+		if (index_mode)
+			ret = index_mode_to_gma(s, 1, gma);
+		else
+			ret = cmd_address_audit(s, gma,
+					sizeof(u64), index_mode);
 	}
 	/* Check notify bit */
 	if ((cmd_val(s, 0) & (1 << 8)))
-- 
2.15.1