[PATCH v5] 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")

v5: refine code logic to handle index_mode.
v4: call cmd_address_audit for new address converted from index.
v3: handle index mode to gma conversion within cmd handler itself.
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 | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
index b420919279c7..083ba64c8f5d 100644
--- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
+++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
@@ -1077,6 +1077,8 @@ static int cmd_handler_pipe_control(struct parser_exec_state *s)
 	bool index_mode = false;
 	unsigned int post_sync;
 	int ret = 0;
+	u32 hws_gpa;
+	u32 val;
 
 	post_sync = (cmd_val(s, 1) & PIPE_CONTROL_POST_SYNC_OP_MASK) >> 14;
 
@@ -1100,6 +1102,15 @@ static int cmd_handler_pipe_control(struct parser_exec_state *s)
 					index_mode = true;
 				ret |= cmd_address_audit(s, gma, sizeof(u64),
 						index_mode);
+				if (ret)
+					return ret;
+				if (index_mode) {
+					hws_gpa = s->vgpu->hws_pga[s->ring_id];
+					gma = hws_gpa + gma;
+					patch_value(s, cmd_ptr(s, 2), gma);
+					val = cmd_val(s, 1) & (~(1 << 21));
+					patch_value(s, cmd_ptr(s, 1), val);
+				}
 			}
 		}
 	}
@@ -1598,6 +1609,8 @@ static int cmd_handler_mi_flush_dw(struct parser_exec_state *s)
 	unsigned long gma;
 	bool index_mode = false;
 	int ret = 0;
+	u32 hws_gpa;
+	u32 val;
 
 	/* Check post-sync and ppgtt bit */
 	if (((cmd_val(s, 0) >> 14) & 0x3) && (cmd_val(s, 1) & (1 << 2))) {
@@ -1608,6 +1621,15 @@ static int cmd_handler_mi_flush_dw(struct parser_exec_state *s)
 		if (cmd_val(s, 0) & (1 << 21))
 			index_mode = true;
 		ret = cmd_address_audit(s, gma, sizeof(u64), index_mode);
+		if (ret)
+			return ret;
+		if (index_mode) {
+			hws_gpa = s->vgpu->hws_pga[s->ring_id];
+			gma = hws_gpa + gma;
+			patch_value(s, cmd_ptr(s, 1), gma);
+			val = cmd_val(s, 0) & (~(1 << 21));
+			patch_value(s, cmd_ptr(s, 0), val);
+		}
 	}
 	/* Check notify bit */
 	if ((cmd_val(s, 0) & (1 << 8)))
-- 
2.15.1