Re: [PATCH v2 1/1] cxl/test: Update mock dev array before calling platform_device_add()

[Alison Schofield]

On Wed, May 20, 2026 at 08:14:57PM +0800, Li Ming wrote:
> CXL test environment hits the following error sometimes.
> 
>  cxl_mem mem9: endpoint7 failed probe
> 
> All mock memdevs are platform firmware devices added by cxl_test module,
> and cxl_test module also provides a platform device driver for them to
> create a memdev device to CXL subsystem. cxl_test module uses
> cxl_rcd/mem_single/mem arrays to store different types of mock memdevs.
> CXL drivers calls registered mock functions for a mock memdev by
> checking if a given memdev is in these arrays.
> 
> When cxl_test module adds these mock memdevs, it always calls
> platform_device_add() before adding them to a suitable mock memdev
> array. However, there is a small window where CXL drivers calls mock
> function for a added memdev before it added to a mock memdev array. In
> above case, cxl endpoint driver considers a added memdev was not a mock
> memdev, then calling devm_cxl_endpoint_decoders_setup() for it rather
> than mock_endpoint_decoders_setup().
> 
> An appropriate solution is that adding a new mock device to a mock
> device array before calling platform_device_add() for it. It can
> guarantee the new mock device is visible to CXL subsystem.
> 
> This patch introduces a new helped called cxl_mock_platform_device_add()
> to handle the issue, and uses the function for all mock devices addition.
> 

Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>



> Fixes: 3a2b97b3210b ("cxl/test: Improve init-order fidelity relative to real-world systems")
> Signed-off-by: Li Ming <ming.li@xxxxxxxxxxxx>
> ---
> Changes from v1:
> - Rebase to v7.1-rc4.
> - Introduce a new helper to handle the issue. (Alison)
> - Use new helper for all mock device addition.
> ---
>  tools/testing/cxl/test/cxl.c | 105 ++++++++++++++---------------------
>  1 file changed, 43 insertions(+), 62 deletions(-)
>