Re: [RFC PATCH 3/3] cxl/test: Exercise Type-2 automatic region creation

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Failure to restore a previously-enabled manual decoder permanently destroys its manual configuration across unbind/rebind cycles.
--

--- Patch [3]: [RFC PATCH 3/3] cxl/test: Exercise Type-2 automatic region creation ---
commit e8d600bcac1235041afc295954c1b2f226a9c8d7
Author: Richard Cheng <icheng@nvidia.com>

cxl/test: Exercise Type-2 automatic region creation

This patch adds a second mock Type-2 accelerator with an independent
single-target CFMWS and an uncommitted manual DEVMEM decoder. It verifies
that devm_cxl_probe_mem() creates the missing region and preserves the manual
decoder config after reset so the fallback remains available across unbind and
rebind.

> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 8ab2ce1262f30..305a0c3705da4 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c

[ ... ]

> @@ -1121,7 +1159,9 @@ static enum cxld_init_type get_decoder_init_type(struct cxl_decoder *cxld,
>  			    MOCK_DECODER_INIT_TYPE3_AUTO;
>  }
>  
> -static bool mock_decoder_handle_saved(struct cxl_decoder *cxld, struct cxl_test_decoder *td)
> +static bool mock_decoder_handle_saved(struct cxl_decoder *cxld,
> +				      struct cxl_test_decoder *td,
> +				      struct platform_device *pdev)
>  {
>  	bool enabled;
>  
> @@ -1133,6 +1173,11 @@ static bool mock_decoder_handle_saved(struct cxl_decoder *cxld, struct cxl_test_
>  	if (enabled)
>  		return !cxld_registry_restore(cxld, td);
>  
> +	if (is_type2_manual_decoder(cxld, pdev)) {

[Severity: Medium]
If cxld_registry_restore() fails, does this bypass the manual fallback logic?

Looking at the preceding lines:

	if (enabled)
		return !cxld_registry_restore(cxld, td);

If the decoder was enabled but cxld_registry_restore() fails (e.g., due to a
DPA reservation error), this function returns immediately. 

Since cxld_registry_restore() internally calls init_disabled_mock_decoder()
on failure, the decoder is forcefully reverted to a HOSTONLYMEM state instead
of the intended DEVMEM fallback state.

Would it be better to fall through to the is_type2_manual_decoder() check
when cxld_registry_restore() fails, so the manual configuration isn't lost
across unbind and rebind cycles?

> +		init_type2_manual_decoder(to_cxl_endpoint_decoder(&cxld->dev));
> +		return false;
> +	}
> +
>  	init_disabled_mock_decoder(cxld);
>  	return false;
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260805074042.30173-1-icheng@nvidia.com?part=3