From: "Koralahalli Channabasappa, Smita" <skoralah@amd.com>
To: Borislav Petkov <bp@alien8.de>,
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@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 11:58:58 -0500 [thread overview]
Message-ID: <00f4a0ab-f241-6674-f37f-623f3d9a8337@amd.com> (raw)
In-Reply-To: <YXfSGW1i5dLsiX84@zn.tnic>
Hi Boris,
On 10/26/21 5:02 AM, Borislav Petkov wrote:
> On Tue, Oct 19, 2021 at 06:36:38PM -0500, Smita Koralahalli wrote:
>> MCA handlers check the valid bit in each status register (MCA_STATUS[Val])
>> and will likely ignore signatures if the valid bit is not set.
>>
>> Warn the user if the valid bit is not set before doing error injection.
>>
>> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
>> ---
>> v2:
>> Added a warning statement instead of setting the valid bit.
>> ---
>> arch/x86/kernel/cpu/mce/inject.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
>> index 601efd104bb4..a993dc3d0333 100644
>> --- a/arch/x86/kernel/cpu/mce/inject.c
>> +++ b/arch/x86/kernel/cpu/mce/inject.c
>> @@ -487,6 +487,9 @@ static void do_inject(void)
>>
>> i_mce.tsc = rdtsc_ordered();
>>
>> + if (!(i_mce.status & MCI_STATUS_VAL))
>> + pr_warn("Handlers might ignore signatures with Val=0 in MCA_STATUS\n");
>> +
>> if (i_mce.misc)
>> i_mce.status |= MCI_STATUS_MISCV;
>>
>> --
> So what's the real reason for this?
>
> You've injected and you didn't get any feedback and were wondering why?
>
> If handlers ignore !VAL MCEs, why don't you simply set it
> unconditionally on entry to do_inject()?
Like how it was done here?
https://lkml.kernel.org/r/20210915232739.6367-3-Smita.KoralahalliChannabasappa@amd.com
Thanks,
next prev parent reply other threads:[~2021-10-26 16:59 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 [this message]
2021-10-26 17:15 ` Borislav Petkov
2021-10-26 18:53 ` Koralahalli Channabasappa, Smita
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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