From: Robert Richter <rrichter@amd.com>
To: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: Borislav Petkov <bp@alien8.de>,
linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org,
tony.luck@intel.com, x86@kernel.org, Avadhut.Naik@amd.com,
John.Allen@amd.com
Subject: Re: [PATCH v2 07/16] x86/mce/amd: Simplify DFR handler setup
Date: Thu, 2 May 2024 20:48:34 +0200 [thread overview]
Message-ID: <ZjPgAoFZXQDsWMJ_@rric.localdomain> (raw)
In-Reply-To: <a5f623ba-6df1-42f1-a709-aafa59b004ba@amd.com>
On 02.05.24 12:02:02, Yazen Ghannam wrote:
> On 4/30/24 2:06 PM, Borislav Petkov wrote:
> > On Mon, Apr 29, 2024 at 08:34:37PM +0200, Robert Richter wrote:
> > > After looking a while into it I think the issue was the following:
> > >
> > > IBS offset was not enabled by firmware, but MCE already was (due to
> > > earlier setup). And mce was (maybe) not on all cpus and only one cpu
> > > per socket enabled. The IBS vector should be enabled on all cpus. Now
> > > firmware allocated offset 1 for mce (instead of offset 0 as for
> > > k8). This caused the hardcoded value (offset 1 for IBS) to be already
> > > taken. Also, hardcoded values couldn't be used at all as this would
> > > have not been worked on k8 (for mce). Another issue was to find the
> > > next free offset as you couldn't examine just the current cpu. So even
> > > if the offset on the current was available, another cpu might have
> > > that offset already in use. Yet another problem was that programmed
> > > offsets for mce and ibs overlapped each other and the kernel had to
> > > reassign them (the ibs offset).
> > >
> > > I hope a remember correctly here with all details.
> >
> > I think you're remembering it correct because after I read this, a very
> > very old and dormant brain cell did light up in my head and said, oh
> > yeah, that definitely rings a bell!
> >
> > :-P
> >
> > Yazen, this is the type of mess I was talking about.
> >
>
> Yep, I see what you mean. Definitely a pain :/
>
> So is this the only known issue? And was it encountered in production
> systems? Were/are people using IBS on K8 (Family Fh) systems? I know
> that perf got support at this time, but do people still use it?
>
> Just as an example, this project has Family 10h as the earliest supported.
> https://github.com/jlgreathouse/AMD_IBS_Toolkit
No, IBS was introduced with 10h, but the eilvt offset came already
with k8, but with only one entry. That affected productions systems
and BIOSes.
>
> My thinking is that we can simplify the code if there are no practical
> issues. And we can address any reported issues as they come.
>
> If you think that's okay, then I can continue with this particular clean
> up. If not, then at least we have some more context here.
The general approach to use the preprogrammed offsets looks good to
me. Though, existing code [1] checks the offset and reapplies a
hardcoded value of 2 if it is zero. I don't know the history of
this. However, it would be great if that code could be simplified.
-Robert
[1] commit 24fd78a81f6d ("x86/mce/amd: Introduce deferred error interrupt handler")
>
> I'm sure there will be more topics like this when redoing the MCA init path.
>
> :)
>
> Thanks,
> Yazen
next prev parent reply other threads:[~2024-05-02 18:48 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-04 15:13 [PATCH v2 00/16] MCA Updates Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 01/16] x86/mce: Define mce_setup() helpers for common and per-CPU fields Yazen Ghannam
2024-04-16 10:02 ` Borislav Petkov
2024-04-17 13:50 ` Yazen Ghannam
2024-04-22 8:13 ` Borislav Petkov
2024-04-04 15:13 ` [PATCH v2 02/16] x86/mce: Use mce_setup() helpers for apei_smca_report_x86_error() Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 03/16] x86/mce/amd: Use fixed bank number for quirks Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 04/16] x86/mce/amd: Look up bank type by IPID Yazen Ghannam
2024-04-23 17:06 ` Borislav Petkov
2024-04-23 19:16 ` Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 05/16] x86/mce/amd: Clean up SMCA configuration Yazen Ghannam
2024-04-23 19:06 ` Borislav Petkov
2024-04-23 19:32 ` Yazen Ghannam
2024-04-24 2:29 ` Borislav Petkov
2024-04-24 13:44 ` Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 06/16] x86/mce/amd: Prep DFR handler before enabling banks Yazen Ghannam
2024-04-24 18:34 ` Borislav Petkov
2024-04-25 13:31 ` Yazen Ghannam
2024-04-29 12:38 ` Borislav Petkov
2024-04-29 13:22 ` Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 07/16] x86/mce/amd: Simplify DFR handler setup Yazen Ghannam
2024-04-24 19:06 ` Borislav Petkov
2024-04-25 14:12 ` Yazen Ghannam
2024-04-29 12:59 ` Borislav Petkov
2024-04-29 13:56 ` Yazen Ghannam
2024-04-29 14:12 ` Borislav Petkov
2024-04-29 14:25 ` Yazen Ghannam
2024-04-30 13:47 ` Borislav Petkov
2024-04-29 18:34 ` Robert Richter
2024-04-30 18:06 ` Borislav Petkov
2024-05-02 16:02 ` Yazen Ghannam
2024-05-02 18:48 ` Robert Richter [this message]
2024-05-04 14:37 ` Borislav Petkov
2024-04-04 15:13 ` [PATCH v2 08/16] x86/mce/amd: Clean up enable_deferred_error_interrupt() Yazen Ghannam
2024-04-29 13:12 ` Borislav Petkov
2024-04-29 14:18 ` Yazen Ghannam
2024-05-04 14:41 ` Borislav Petkov
2024-04-04 15:13 ` [PATCH v2 09/16] x86/mce: Unify AMD THR handler with MCA Polling Yazen Ghannam
2024-04-29 13:40 ` Borislav Petkov
2024-04-29 14:36 ` Yazen Ghannam
2024-05-04 14:52 ` Borislav Petkov
2024-05-07 16:25 ` Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 10/16] x86/mce: Unify AMD DFR " Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 11/16] x86/mce: Skip AMD threshold init if no threshold banks found Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 12/16] x86/mce/amd: Support SMCA Corrected Error Interrupt Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 13/16] x86/mce: Add wrapper for struct mce to export vendor specific info Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 14/16] x86/mce, EDAC/mce_amd: Add support for new MCA_SYND{1,2} registers Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 15/16] x86/mce/apei: Handle variable register array size Yazen Ghannam
2024-04-04 15:13 ` [PATCH v2 16/16] EDAC/mce_amd: Add support for FRU Text in MCA Yazen Ghannam
2024-04-05 16:06 ` Luck, Tony
2024-04-07 13:19 ` Yazen Ghannam
2024-04-08 19:47 ` Naik, Avadhut
2024-04-08 19:57 ` Luck, Tony
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