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From: "Jan Beulich" <JBeulich@suse.com>
To: Ashok Raj <ashok.raj@intel.com>, Chao Gao <chao.gao@intel.com>
Cc: Sergey Dyasli <sergey.dyasli@citrix.com>,
	Kevin Tian <kevin.tian@intel.com>, Wei Liu <wei.liu2@citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	tglx@linutronix.de, Borislav Petkov <bp@suse.de>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [PATCH v6 11/12] x86/microcode: Synchronize late microcode loading
Date: Wed, 13 Mar 2019 02:02:55 -0600	[thread overview]
Message-ID: <5C88B92F020000780021DF64@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <5C88B746020000780021DF4D@prv1-mh.provo.novell.com>

>>> On 13.03.19 at 08:54, <JBeulich@suse.com> wrote:
>>>> On 13.03.19 at 06:02, <chao.gao@intel.com> wrote:
>> On Tue, Mar 12, 2019 at 05:07:51PM -0700, Raj, Ashok wrote:
>>>On Mon, Mar 11, 2019 at 03:57:35PM +0800, Chao Gao wrote:
>>>> +    if ( cpu == cpumask_first(per_cpu(cpu_sibling_mask, cpu)) )
>>>> +        ret = microcode_update_cpu();
>>>
>>>Does ret have any useful things on if the update failed? Doesn't seem 
>>>to be used before you overwrite later in collect_cpu_info()?
>> 
>> It has the reason of failure on error. Actally, there are two reasons:
>> one is no patch of newer revision, the other is we tried to update but
>> the microcode revision didn't change. I can check this return value and
>> print more informative message to admin. And furthermore, for the
>> latter, we can remove the ucode patch from caches to address Roger's
>> concern expressed in comments to patch 4 & 5.
> 
> Btw, I'm not sure removing such ucode from the cache is appropriate:
> It may well apply elsewhere, unless there's a clear indication that the
> blob is broken. So perhaps there needs to be special casing of -EIO,
> which gets returned when the ucode rev reported by the CPU after
> the update does not match expectations.

An to go one step further, perhaps we should also store more than
just the newest variant for a given pf. If the newest fails to apply
but there is another one newer than what's on a CPU, updating to
that may work, and once that intermediate update worked, the
update to the newest version may then work too.

Jan



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  reply	other threads:[~2019-03-13  8:03 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-11  7:57 [PATCH v6 00/12] improve late microcode loading Chao Gao
2019-03-11  7:57 ` [PATCH v6 01/12] misc/xenmicrocode: Upload a microcode blob to the hypervisor Chao Gao
2019-03-12 15:27   ` Roger Pau Monné
2019-03-13  5:05     ` Chao Gao
2019-03-13  9:24   ` Wei Liu
2019-03-25  9:38   ` Sergey Dyasli
2019-04-02  2:26     ` Chao Gao
2019-03-11  7:57 ` [PATCH v6 02/12] microcode/intel: use union to get fields without shifting and masking Chao Gao
2019-03-12 15:33   ` Roger Pau Monné
2019-03-12 16:43     ` Jan Beulich
2019-03-12 18:23       ` Wei Liu
2019-03-11  7:57 ` [PATCH v6 03/12] microcode/intel: extend microcode_update_match() Chao Gao
2019-03-11  7:57 ` [PATCH v6 04/12] microcode: introduce a global cache of ucode patch Chao Gao
2019-03-12 16:53   ` Roger Pau Monné
2019-03-12 23:31     ` Raj, Ashok
2019-03-13  5:28     ` Chao Gao
2019-03-13  7:39     ` Jan Beulich
2019-03-13 10:30       ` Andrew Cooper
2019-03-13 17:04         ` Andrew Cooper
2019-03-14  7:42           ` Jan Beulich
2019-03-13 16:36   ` Sergey Dyasli
2019-03-14  1:39     ` Chao Gao
2019-03-11  7:57 ` [PATCH v6 05/12] microcode: only save compatible ucode patches Chao Gao
2019-03-12 17:03   ` Roger Pau Monné
2019-03-13  7:45     ` Jan Beulich
2019-03-11  7:57 ` [PATCH v6 06/12] microcode: remove struct ucode_cpu_info Chao Gao
2019-03-11  7:57 ` [PATCH v6 07/12] microcode: remove pointless 'cpu' parameter Chao Gao
2019-03-11  7:57 ` [PATCH v6 08/12] microcode: split out apply_microcode() from cpu_request_microcode() Chao Gao
2019-03-11  7:57 ` [PATCH v6 09/12] microcode: remove struct microcode_info Chao Gao
2019-03-11  7:57 ` [PATCH v6 10/12] microcode/intel: Writeback and invalidate caches before updating microcode Chao Gao
2019-03-21 11:08   ` Sergey Dyasli
2019-03-11  7:57 ` [PATCH v6 11/12] x86/microcode: Synchronize late microcode loading Chao Gao
2019-03-13  0:07   ` Raj, Ashok
2019-03-13  5:02     ` Chao Gao
2019-03-13  7:54       ` Jan Beulich
2019-03-13  8:02         ` Jan Beulich [this message]
2019-03-14 12:39           ` Andrew Cooper
2019-03-14 18:57             ` Raj, Ashok
2019-03-14 20:25               ` Thomas Gleixner
2019-03-15  9:40                 ` Andrew Cooper
2019-03-15 10:44                   ` Thomas Gleixner
2019-03-14 13:01           ` Chao Gao
2019-03-14 13:08             ` Jan Beulich
2019-03-11  7:57 ` [PATCH v6 12/12] microcode: update microcode on cores in parallel Chao Gao
2019-03-21 12:24   ` [RFC PATCH v6 13/12] microcode: add sequential application policy Sergey Dyasli
2019-03-21 14:25     ` Chao Gao
2019-03-26 16:23     ` Jan Beulich
2019-03-19 20:22 ` [PATCH v6 00/12] improve late microcode loading Woods, Brian
2019-03-19 21:39   ` Woods, Brian
2019-03-20  8:58     ` Chao Gao

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