Re: [RFC PATCH 0/6] CCIX Protocol Error reporting

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Thu, 6 Jun 2019 20:36:48 +0800
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:

Hi All,

I'm looking for some reviews on this series if anyone has time to take
a look.  Rasdaemon patches to match with this are on linux-edac but
are waiting on the tracepoints merging.

I'm not currently planning to upstream the qemu injection patches
used to test this but anyone would like those I can certainly put
a public branch up somewhere.

Thanks,

Jonathan

> UEFI 2.8 defines a new CPER record Appendix N for CCIX Protocol Error Records
> (PER). www.uefi.org
> 
> These include Protocol Error Record logs which are defined in the
> CCIX 1.0 Base Specification www.ccixconsortium.com.
> 
> Handling of coherency protocol errors is complex and how Linux does this
> will take some time to evolve.  For now, fatal errors are handled via the
> usual means and everything else is reported.
> 
> There are 6 types of error defined, covering:
> * Memory errors
> * Cache errors
> * Address translation unit errors
> * CCIX port errors 
> * CCIX link errors
> * Agent internal errors.
> 
> The set includes tracepoints to report the errors to RAS Daemon and a patch
> set for RAS Daemon will follow shortly.
> 
> There are several open questions for this RFC.
> 1. Reporting of vendor data.  We have little choice but to do this via a
>    dynamic array as these blocks can take arbitrary size. I had hoped
>    no one would actually use these given the odd mismatch between a
>    standard error structure and non standard element, but there are
>    already designs out there that do use it.
> 2. The trade off between explicit tracepoint fields, on which we might
>    want to filter, and the simplicity of a blob. I have gone for having
>    the whole of the block specific to the PER error type in an opaque blob.
>    Perhaps this is not the right balance?
> 3. Whether defining 6 new tracepoints is sensible. I think it is:
>    * They are all defined by the CCIX specification as independant error
>      classes.
>    * Many of them can only be generated by particular types of agent.
>    * The handling required will vary widely depending on types.
>      In the kernel some map cleanly onto existing handling. Keeping the
>      whole flow separate will aide this. They vary by a similar amount
>      in scope to the RAS errors found on an existing system which have
>      independent tracepoints.
>    * Separating them out allows for filtering on the tracepoints by
>      elements that are not shared between them.
>    * Muxing the lot into one record type can lead to ugly code both in
>      kernel and in userspace.
> 
> Rasdaemon patches will follow shortly.
> 
> This patch is being distributed by the CCIX Consortium, Inc. (CCIX) to
> you and other parties that are paticipating (the "participants") in the
> Linux kernel with the understanding that the participants will use CCIX's
> name and trademark only when this patch is used in association with the
> Linux kernel and associated user space.
> 
> CCIX is also distributing this patch to these participants with the
> understanding that if any portion of the CCIX specification will be
> used or referenced in the Linux kernel, the participants will not modify
> the cited portion of the CCIX specification and will give CCIX propery
> copyright attribution by including the following copyright notice with
> the cited part of the CCIX specification:
> "© 2019 CCIX CONSORTIUM, INC. ALL RIGHTS RESERVED."
> 
> Jonathan Cameron (6):
>   efi / ras: CCIX Memory error reporting
>   efi / ras: CCIX Cache error reporting
>   efi / ras: CCIX Address Translation Cache error reporting
>   efi / ras: CCIX Port error reporting
>   efi / ras: CCIX Link error reporting
>   efi / ras: CCIX Agent internal error reporting
> 
>  drivers/acpi/apei/Kconfig        |   8 +
>  drivers/acpi/apei/ghes.c         |  59 ++
>  drivers/firmware/efi/Kconfig     |   5 +
>  drivers/firmware/efi/Makefile    |   1 +
>  drivers/firmware/efi/cper-ccix.c | 916 +++++++++++++++++++++++++++++++
>  drivers/firmware/efi/cper.c      |   6 +
>  include/linux/cper.h             | 333 +++++++++++
>  include/ras/ras_event.h          | 405 ++++++++++++++
>  8 files changed, 1733 insertions(+)
>  create mode 100644 drivers/firmware/efi/cper-ccix.c
>