From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Borislav Petkov <bp@alien8.de>, Junichi Nomura <j-nomura@ce.jp.nec.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>
Subject: Re: [PATCH 3/2] x86/microcode/intel: Add a helper which gives the microcode revision
Date: Wed, 28 Dec 2016 14:26:24 -0500 [thread overview]
Message-ID: <e7e50f9f-c06a-6ce5-f00e-a5ae854a2ca0@oracle.com> (raw)
In-Reply-To: <20161228125354.GA30537@nazgul.tnic>
On 12/28/2016 07:53 AM, Borislav Petkov wrote:
> On Wed, Dec 28, 2016 at 12:21:20PM +0100, Borislav Petkov wrote:
>> From: Borislav Petkov <bp@suse.de>
>>
>> Intel supplies the microcode revision value in MSR 0x8b
>> (IA32_BIOS_SIGN_ID) after CPUID(1) has been executed. Execute it each
>> time before reading that MSR.
>
> And then, we can go a step further and even do a separate helper which does the
> required steps to read out the microcode revision so that we don't forget them
> next time we change the code.
>
> Provided that works for xen, though, because I need to do the native
> variants but early_init_intel() can call the paravirt *msr() versions
> and I have no idea whether that's kosher on xen pv.
>
> Boris, any objections?
I think this should work. MSR_IA32_UCODE_REV can be natively read and
written with zero without any side effects.
-boris
next prev parent reply other threads:[~2016-12-28 19:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-28 4:39 [PATCH] x86: Fix Intel microcode revision detection Junichi Nomura
2016-12-28 11:18 ` Borislav Petkov
2016-12-28 11:20 ` [PATCH 1/2] x86/CPU: Add native CPUID variants returning a single datum Borislav Petkov
2016-12-28 18:11 ` Andy Lutomirski
2016-12-29 9:30 ` Borislav Petkov
2016-12-31 2:13 ` Andy Lutomirski
2016-12-31 11:09 ` Borislav Petkov
2017-01-03 18:35 ` Andy Lutomirski
2017-01-03 19:48 ` Borislav Petkov
2016-12-28 11:21 ` [PATCH 2/2] x86/microcode: Use native CPUID to tickle out microcode revision Borislav Petkov
2016-12-28 12:53 ` [PATCH 3/2] x86/microcode/intel: Add a helper which gives the " Borislav Petkov
2016-12-28 18:12 ` Andy Lutomirski
2016-12-29 9:36 ` Borislav Petkov
2016-12-28 19:26 ` Boris Ostrovsky [this message]
2016-12-29 9:38 ` Borislav Petkov
[not found] ` <0a84dd78-809f-c1ef-6adc-551a124170ad@ce.jp.nec.com>
2017-01-05 9:39 ` [PATCH] x86: Fix Intel microcode revision detection Borislav Petkov
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