From: "Koralahalli Channabasappa, Smita" <skoralah@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>,
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@amd.com
Subject: Re: [PATCH v2 2/5] x86/mce/inject: Warn the user on a not set valid bit in MCA_STATUS
Date: Tue, 26 Oct 2021 13:53:32 -0500 [thread overview]
Message-ID: <73439c67-b7a3-e43d-511b-86f4a314fa29@amd.com> (raw)
In-Reply-To: <YXg3rIump+CAtgs6@zn.tnic>
On 10/26/21 12:15 PM, Borislav Petkov wrote:
> On Tue, Oct 26, 2021 at 11:58:58AM -0500, Koralahalli Channabasappa, Smita wrote:
> Whoops, sorry about that.
>
> So let's analyze this properly - there are two cases:
>
> 1. warn if VAL=0: what does that bring us? The person doing the injection
> will simply have to set the valid bit and repeat the injection.
>
> I guess "maybe the user wants to inject with Val not set" doesn't make a
> whole lot of sense because nothing will happen - error will get ignored.
>
> So we can do all the warning we want - it will be useless and in some
> cases the user might not even see it.
>
> So it sounds to me like setting the valid bit directly makes a lot more
> sense.
>
> 2. Automatically set VAL=1 to correct any VAL=0 injections.
>
> Yes, we force the VAL bit to 1 and that is not what the user injected
> but the user injecting with VAL=0 will get ignored, i.e., it will be
> pointless.
>
> So we "help" here and set the valid bit.
>
> Anything else I'm missing?
>
> Sorry again for being back'n'forth on this.
Right. We are correcting VAL=0 injections made by the user by setting
valid bit unconditionally.
Not a problem. I could have broken this down in the comments before
coming up with this patch.
I will make the necessary changes and set the valid bit in the next
revision of the patch series.
Thanks,
Smita.
next prev parent reply other threads:[~2021-10-26 18:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 23:36 [PATCH v2 0/5] x86/mce: Handle error injection failures in mce-inject module Smita Koralahalli
2021-10-19 23:36 ` [PATCH v2 1/5] x86/mce/inject: Check if a bank is unpopulated before error injection Smita Koralahalli
2021-10-25 13:56 ` Borislav Petkov
2021-10-25 17:09 ` Koralahalli Channabasappa, Smita
2021-12-08 11:03 ` [tip: ras/core] x86/mce/inject: Check if a bank is populated before injecting tip-bot2 for Smita Koralahalli
2021-10-19 23:36 ` [PATCH v2 2/5] x86/mce/inject: Warn the user on a not set valid bit in MCA_STATUS Smita Koralahalli
2021-10-20 15:06 ` Luck, Tony
2021-10-26 10:02 ` Borislav Petkov
2021-10-26 16:58 ` Koralahalli Channabasappa, Smita
2021-10-26 17:15 ` Borislav Petkov
2021-10-26 18:53 ` Koralahalli Channabasappa, Smita [this message]
2021-10-26 20:25 ` Borislav Petkov
2021-10-19 23:36 ` [PATCH v2 3/5] x86/mce: Use mca_msr_reg() in prepare_msrs() Smita Koralahalli
2021-10-27 11:41 ` Borislav Petkov
2021-10-27 20:19 ` Koralahalli Channabasappa, Smita
2021-10-28 8:53 ` Borislav Petkov
2021-11-01 18:51 ` Koralahalli Channabasappa, Smita
2021-10-19 23:36 ` [PATCH v2 4/5] x86/mce/inject: Check for writes ignored in status registers Smita Koralahalli
2021-10-19 23:36 ` [PATCH v2 5/5] x86/mce/mce-inject: Return error code to userspace from mce-inject module Smita Koralahalli
2021-10-20 15:18 ` Luck, Tony
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