drm/i915/gvt: set the correct default value of CTX STATUS PTR

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@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/gvt/execlist.c b/drivers/gpu/drm/i915/gvt/execlist.c
index 34083731669d8cbe55b94de2e5b3585aa73a7039..6804bf5fec3a4c1ce65c8c6a73255d3788e93c20 100644 (file)
--- 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 intel_vgpu *vgpu, int ring_id)
                        _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;
 }