From: Ingo Molnar <mingo@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
Andy Lutomirski <luto@amacapital.net>,
linux-nvdimm <linux-nvdimm@ml01.01.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Robert <elliott@hpe.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
X86 ML <x86@kernel.org>
Subject: Re: [PATCH v8 3/3] x86, mce: Add __mcsafe_copy()
Date: Mon, 11 Jan 2016 11:44:25 +0100 [thread overview]
Message-ID: <20160111104425.GA29448@gmail.com> (raw)
In-Reply-To: <20160110112635.GC22896@pd.tnic>
* Borislav Petkov <bp@alien8.de> wrote:
> On Sat, Jan 09, 2016 at 05:40:05PM -0800, Tony Luck wrote:
> > BUT ... it's all going to be very messy. We don't have any CPUID
> > capability bits to say whether we support recovery, or which instructions
> > are good/bad choices for recovery.
>
> We can always define synthetic ones and set them after having checked
> MCA capability bits, f/m/s, etc., maybe even based on the list you're
> supplying...
So such a synthetic CPUID bit would definitely be useful.
Also, knowing whether a memcpy function is recoverable or not, should not be
delegated to callers: there should be the regular memcpy APIs, plus new APIs that
do everything they can to provide recoverable memory copies. Whether it's achieved
via flag checking, a function pointer or code patching is an implementation detail
that's not visible to drivers making use of the new facility.
I'd go for the simplest, most robust solution initially, also perhaps with boot
time messages to make sure users know which variant is used and now.
Thanks,
Ingo
WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
Andy Lutomirski <luto@amacapital.net>,
linux-nvdimm <linux-nvdimm@ml01.01.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Robert <elliott@hpe.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
X86 ML <x86@kernel.org>
Subject: Re: [PATCH v8 3/3] x86, mce: Add __mcsafe_copy()
Date: Mon, 11 Jan 2016 11:44:25 +0100 [thread overview]
Message-ID: <20160111104425.GA29448@gmail.com> (raw)
In-Reply-To: <20160110112635.GC22896@pd.tnic>
* Borislav Petkov <bp@alien8.de> wrote:
> On Sat, Jan 09, 2016 at 05:40:05PM -0800, Tony Luck wrote:
> > BUT ... it's all going to be very messy. We don't have any CPUID
> > capability bits to say whether we support recovery, or which instructions
> > are good/bad choices for recovery.
>
> We can always define synthetic ones and set them after having checked
> MCA capability bits, f/m/s, etc., maybe even based on the list you're
> supplying...
So such a synthetic CPUID bit would definitely be useful.
Also, knowing whether a memcpy function is recoverable or not, should not be
delegated to callers: there should be the regular memcpy APIs, plus new APIs that
do everything they can to provide recoverable memory copies. Whether it's achieved
via flag checking, a function pointer or code patching is an implementation detail
that's not visible to drivers making use of the new facility.
I'd go for the simplest, most robust solution initially, also perhaps with boot
time messages to make sure users know which variant is used and now.
Thanks,
Ingo
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next prev parent reply other threads:[~2016-01-11 10:44 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-09 0:04 [PATCH v8 0/3] Machine check recovery when kernel accesses poison Tony Luck
2016-01-09 0:04 ` Tony Luck
2015-12-31 19:40 ` [PATCH v8 2/3] x86, mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries Tony Luck
2015-12-31 19:40 ` Tony Luck
2016-01-08 20:49 ` [PATCH v8 1/3] x86: Expand exception table to allow new handling options Tony Luck
2016-01-08 20:49 ` Tony Luck
2016-01-09 1:52 ` Andy Lutomirski
2016-01-09 1:52 ` Andy Lutomirski
2016-01-09 3:39 ` Brian Gerst
2016-01-09 3:39 ` Brian Gerst
2016-01-09 4:31 ` Brian Gerst
2016-01-09 4:31 ` Brian Gerst
2016-01-09 6:36 ` Andy Lutomirski
2016-01-09 6:36 ` Andy Lutomirski
2016-01-11 23:09 ` Brian Gerst
2016-01-11 23:09 ` Brian Gerst
2016-01-11 23:22 ` Andy Lutomirski
2016-01-11 23:22 ` Andy Lutomirski
2016-01-11 23:48 ` Luck, Tony
2016-01-11 23:48 ` Luck, Tony
2016-01-09 17:45 ` Tony Luck
2016-01-09 17:45 ` Tony Luck
2016-01-09 18:00 ` Andy Lutomirski
2016-01-09 18:00 ` Andy Lutomirski
2016-01-09 19:51 ` Tony Luck
2016-01-09 19:51 ` Tony Luck
2016-01-09 22:32 ` Andy Lutomirski
2016-01-09 22:32 ` Andy Lutomirski
2016-01-10 1:15 ` Tony Luck
2016-01-10 1:15 ` Tony Luck
2016-01-11 0:25 ` Luck, Tony
2016-01-11 0:25 ` Luck, Tony
2016-01-08 21:18 ` [PATCH v8 3/3] x86, mce: Add __mcsafe_copy() Tony Luck
2016-01-08 21:18 ` Tony Luck
2016-01-09 1:49 ` Andy Lutomirski
2016-01-09 1:49 ` Andy Lutomirski
2016-01-09 17:48 ` Tony Luck
2016-01-09 17:48 ` Tony Luck
2016-01-09 17:57 ` Andy Lutomirski
2016-01-09 17:57 ` Andy Lutomirski
2016-01-09 19:39 ` Tony Luck
2016-01-09 19:39 ` Tony Luck
2016-01-09 22:15 ` Dan Williams
2016-01-09 22:15 ` Dan Williams
2016-01-09 22:33 ` Andy Lutomirski
2016-01-09 22:33 ` Andy Lutomirski
2016-01-10 0:23 ` Dan Williams
2016-01-10 0:23 ` Dan Williams
2016-01-10 1:40 ` Tony Luck
2016-01-10 1:40 ` Tony Luck
2016-01-10 11:26 ` Borislav Petkov
2016-01-10 11:26 ` Borislav Petkov
2016-01-11 10:44 ` Ingo Molnar [this message]
2016-01-11 10:44 ` Ingo Molnar
2016-01-13 23:22 ` Tony Luck
2016-01-13 23:22 ` Tony Luck
2016-01-14 4:39 ` Borislav Petkov
2016-01-14 4:39 ` Borislav Petkov
2016-01-30 0:35 ` Tony Luck
2016-01-30 0:35 ` Tony Luck
2016-01-30 10:28 ` Borislav Petkov
2016-01-30 10:28 ` Borislav Petkov
2016-02-01 23:10 ` Tony Luck
2016-02-01 23:10 ` Tony Luck
2016-02-01 23:16 ` Dan Williams
2016-02-01 23:16 ` Dan Williams
2016-01-12 0:26 ` Luck, Tony
2016-01-12 0:26 ` Luck, Tony
2016-01-12 0:30 ` Andy Lutomirski
2016-01-12 0:30 ` Andy Lutomirski
2016-01-12 0:37 ` Andy Lutomirski
2016-01-12 0:37 ` Andy Lutomirski
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