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[0/2] watchdog/hpwdt: Cleanup Claiming NMI

Message ID 20231109024407.120856-1-jerry.hoemann@hpe.com
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Series watchdog/hpwdt: Cleanup Claiming NMI | expand

Message

Jerry Hoemann Nov. 9, 2023, 2:44 a.m. UTC 
In addition to being a watchdog, hpwdt participates in error
containmnet on ProLiant systems.

On legacy platforms (Gen 8/Gen 9 and earlier) Fatal IO errors would be
signaled as an IO CHECK NMI with expectation that hpwdt would be present
to receive the NMI and crash the systems thus containing the error.

A problem was that hwpdt did not discriminate enough in accepting NMIs.
This could lead to problems if an NMI generated for another subsystems
was not claimed by that subsystem and became UNKNOWN and was claimed
by hpwdt.  Application profiling was such an example.  While, profiling
issue was fixed, hpwdt should avoid claiming NMI not intended for it.

In iLO 5 time frame, checks were added to make hpwdt more selective
in claiming NMI.  This patchset cleans up the checks and enables it
for future versions of iLO.


Jerry Hoemann (2):
  watchdog/hpwdt: Only claim UNKNOWN NMI if from iLO
  watchdog/hpwdt: Remove checks on ilo5

 drivers/watchdog/hpwdt.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

Comments

Jerry Hoemann Nov. 27, 2023, 3:16 a.m. UTC | #1 
On Wed, Nov 08, 2023 at 07:44:05PM -0700, Jerry Hoemann wrote:
> In addition to being a watchdog, hpwdt participates in error
> containmnet on ProLiant systems.
> 
> On legacy platforms (Gen 8/Gen 9 and earlier) Fatal IO errors would be
> signaled as an IO CHECK NMI with expectation that hpwdt would be present
> to receive the NMI and crash the systems thus containing the error.
> 
> A problem was that hwpdt did not discriminate enough in accepting NMIs.
> This could lead to problems if an NMI generated for another subsystems
> was not claimed by that subsystem and became UNKNOWN and was claimed
> by hpwdt.  Application profiling was such an example.  While, profiling
> issue was fixed, hpwdt should avoid claiming NMI not intended for it.
> 
> In iLO 5 time frame, checks were added to make hpwdt more selective
> in claiming NMI.  This patchset cleans up the checks and enables it
> for future versions of iLO.
> 

Hi Guenter,

Was there a problem with this patch set?

Thanks

Jerry


> 
> Jerry Hoemann (2):
>   watchdog/hpwdt: Only claim UNKNOWN NMI if from iLO
>   watchdog/hpwdt: Remove checks on ilo5
> 
>  drivers/watchdog/hpwdt.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> -- 
> 2.41.0