From: Borislav Petkov <bp@alien8.de>
To: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Cc: x86@kernel.org, linux-edac@vger.kernel.org,
linux-kernel@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Yazen Ghannam <yazen.ghannam@amd.com>
Subject: Re: [PATCH v4 1/2] x86/mce: Check for writes ignored in MCA_STATUS register
Date: Tue, 3 May 2022 23:14:05 +0200 [thread overview]
Message-ID: <YnGbHcMkLCsauzXF@zn.tnic> (raw)
In-Reply-To: <3fd01af5-c665-6dbb-4ed4-dfc39109d63a@amd.com>
On Mon, May 02, 2022 at 08:28:47PM -0700, Smita Koralahalli wrote:
> I'm bit more inclined towards your previous approach of
> hw_injection_possible
> check in do_inject(). This seems better than doing it in flags_write().
If you don't do it in flags_write() then the user would do
echo "hw" > flags
the command will succeed and the user will think that hw injection is
possible and then wonder why it fails later.
I even actually think that in the first run, when hw_injection_possible
is not determined yet, you should try to poke at MCi_STATUS of some
non-reserved bank - and we enumerate which those are at boot in
__mcheck_cpu_check_banks(), so you can pick a random, non-RAZ bank, save
its MCi_STATUS, try to write it and if it succeeds, restore it.
This way you'll determine whether hw injection is possible, store it
in the static hw_injection_possible and then query only that variable.
I.e., you'll have to poke that MCi_STATUS only once on driver init. And
this way it'll be the most optimal, methinks.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-05-03 21:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 23:36 [PATCH v4 0/2] x86/mce: Handle error injection failure in mce-inject module Smita Koralahalli
2022-02-14 23:36 ` [PATCH v4 1/2] x86/mce: Check for writes ignored in MCA_STATUS register Smita Koralahalli
2022-04-06 16:08 ` Borislav Petkov
2022-04-13 19:16 ` Smita Koralahalli
2022-04-13 20:19 ` Borislav Petkov
2022-04-19 3:24 ` Smita Koralahalli
2022-04-20 9:17 ` Borislav Petkov
2022-04-21 19:10 ` Smita Koralahalli
2022-04-24 22:32 ` Borislav Petkov
2022-05-03 3:28 ` Smita Koralahalli
2022-05-03 21:14 ` Borislav Petkov [this message]
2022-05-05 19:03 ` Smita Koralahalli
2022-06-28 10:17 ` [tip: ras/core] x86/mce: Check whether writes to MCA_STATUS are getting ignored tip-bot2 for Smita Koralahalli
2022-02-14 23:36 ` [PATCH v4 2/2] x86/mce/mce-inject: Return appropriate error code if CPUs are offline Smita Koralahalli
2022-03-11 20:55 ` [PATCH v4 0/2] x86/mce: Handle error injection failure in mce-inject module Koralahalli Channabasappa, Smita
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