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

[Li Ming]

在 2026/5/21 15:25, Alison Schofield 写道:
> 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>

Hi Alison,


I missed that you mentioned putting platform_device_alloc() into the 
helper. I will send out v3 for that.


Ming

> > 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(-)