[PATCH 4.10 51/69] drm/i915/gvt: set the correct default value of CTX STATUS PTR

[Greg Kroah-Hartman]

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Min He <min.he@xxxxxxxxx>

commit a34f83639490a5cc11a9d5c1b3773d4b6eb69a9e upstream.

Fix wrong initial csb read pointer value. This fixes the random
engine timeout issue in guest when guest boots up.

Fixes: 8453d674ae7e ("drm/i915/gvt: vGPU execlist virtualization")
Signed-off-by: Min He <min.he@xxxxxxxxx>
Signed-off-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/gvt/execlist.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/gvt/execlist.c
+++ b/drivers/gpu/drm/i915/gvt/execlist.c
@@ -778,7 +778,8 @@ static void init_vgpu_execlist(struct in
 			_EL_OFFSET_STATUS_PTR);
 
 	ctx_status_ptr.dw = vgpu_vreg(vgpu, ctx_status_ptr_reg);
-	ctx_status_ptr.read_ptr = ctx_status_ptr.write_ptr = 0x7;
+	ctx_status_ptr.read_ptr = 0;
+	ctx_status_ptr.write_ptr = 0x7;
 	vgpu_vreg(vgpu, ctx_status_ptr_reg) = ctx_status_ptr.dw;
 }