Re: [PATCH v12 0/3] cxl, EINJ: Update EINJ for CXL error types

[Tony Luck <tony.luck@intel.com>]

On Wed, Feb 14, 2024 at 02:07:06PM -0600, Ben Cheatham wrote:
> v12 Changes:
> 	- Rebase onto v6.8-rc4
> 	- Squash Kconfig patch into patch 2/3 (Jonathan)
> 	- Change CONFIG_CXL_EINJ from "depends on ACPI_APEI_EINJ >= CXL_BUS"
> 	  to "depends on ACPI_APEI_EINJ = CXL_BUS"
> 	- Drop "ACPI, APEI" part of commit message title and use just EINJ
> 	instead (Dan)
> 	- Add protocol error types to "einj_types" documentation (Jonathan)
> 	- Change 0xffff... constants to use GENMASK()
> 	- Drop param* variables and use constants instead in cxl error
> 	  inject functions (Jonathan)
> 	- Add is_cxl_error_type() helper function in einj.c (Jonathan)
> 	- Remove a stray function declaration in einj-cxl.h (Jonathan)
> 	- Comment #else/#endifs with corresponding #if/#ifdef in
> 	einj-cxl.h (Jonathan)
> 
> v11 Changes:
> 	- Drop patch 2/6 (Add CXL protocol error defines) and put the
> 	  defines in patch 4/6 instead (Dan)
> 	- Add Dan's reviewed-by
> 
> The new CXL error types will use the Memory Address field in the
> SET_ERROR_TYPE_WITH_ADDRESS structure in order to target a CXL 1.1
> compliant memory-mapped downstream port. The value of the memory address
> will be in the port's MMIO range, and it will not represent physical
> (normal or persistent) memory.
> 
> Add the functionality for injecting CXL 1.1 errors to the EINJ module,
> but not through the EINJ legacy interface under /sys/kernel/debug/apei/einj.
> Instead, make the error types available under /sys/kernel/debug/cxl.
> This allows for validating the MMIO address for a CXL 1.1 error type
> while also not making the user responsible for finding it.

I tried this series on an Intel Icelake (which as far as I know
doesn't support CXL).

Couple of oddities:

1) I built as a module (CONFIG_ACPI_APEI_EINJ=m) like I normally do.
   But this was autoloaded and EINJ initialized during boot:

[   33.909111] EINJ: Error INJection is initialized.

I'm wondering if that might be a problem for anyone that likes to
leave the einj module not loaded until they have some need to
inject errors.


2) Even though my system doesn't have any CXL support, I found this:

# cat /sys/kernel/debug/cxl/einj_types
0x00001000      CXL.cache Protocol Correctable

What does this mean?

Using ras-tools I injected some DDR memory errors. So legacy
functionality still works OK.

-Tony