[PATCH v2] drm/i915/gvt: Handle GEN9_WM_CHICKEN3 with F_CMD_ACCESS for BXT.

[Colin Xu]

Recent patch introduce strict check on scanning cmd:
Commit 8d458ea0ec33 ("drm/i915/gvt: return error on cmd access")

Before 8d458ea0ec33, if cmd_reg_handler() checks that a cmd access a mmio
that not marked as F_CMD_ACCESS, it simply returns 0 and log an error.
Now it will return -EBADRQC which will cause the workload fail to submit.

On BXT, i915 applies WaClearHIZ_WM_CHICKEN3 which will program
GEN9_WM_CHICKEN3 by LRI when init wa ctx. If it has no F_CMD_ACCESS flag,
vgpu will fail to start. Also add F_MODE_MASK since it's mode mask reg.

v2: Refresh commit message to elaborate issue symptom in detail.

Signed-off-by: Colin Xu <colin.xu at intel.com>
---
 drivers/gpu/drm/i915/gvt/handlers.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index cf2a4020949d..e32a69fabda3 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -3205,6 +3205,8 @@ static int init_bxt_mmio_info(struct intel_gvt *gvt)
 	MMIO_D(GEN8_L3SQCREG1, D_BXT);
 
 	MMIO_DFH(GEN9_CTX_PREEMPT_REG, D_BXT, F_CMD_ACCESS, NULL, NULL);
+	MMIO_DFH(GEN9_WM_CHICKEN3, D_BXT,
+		 F_MODE_MASK | F_CMD_ACCESS, NULL, NULL);
 
 	return 0;
 }
-- 
2.18.0