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From: Wanpeng Li <kernellwp@gmail.com>
To: Borislav Petkov <bp@alien8.de>
Cc: LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH] KVM: X86: Allow userspace to define the microcode version
Date: Mon, 26 Feb 2018 19:25:28 +0800	[thread overview]
Message-ID: <CANRm+Cxw2-8Cf+6cg_yZC+SD66uNA5RO+ZaoHHmkpHLzjCih=A@mail.gmail.com> (raw)
In-Reply-To: <20180226111630.GB4377@pd.tnic>

2018-02-26 19:16 GMT+08:00 Borislav Petkov <bp@alien8.de>:
> On Mon, Feb 26, 2018 at 07:02:29PM +0800, Wanpeng Li wrote:
>> > So a guest will have *two* microcode revisions - both of which are most
>> > likely wrong?!
>>
>> Just one revision.
>
> So what does "the non-sensical value which is written by the guest will
> not reflect to guest-visible microcode revision" even mean then?
>
> cat /proc/cpuinfo
>
> in the guest shows what exactly?
>
> And what would RDMSR 0x8b show then?

Both are the same values set by kvm userspace.

>
>> https://lkml.org/lkml/2017/12/9/29 The original discussion explain in
>> more details.
>

> approach. Instead, the kernel should not look at microcode revisions if
> it runs virtualized.

This is correct. The link explains why the userspace sets microcode
revision is still needed.

Regards,
Wanpeng Li

  reply	other threads:[~2018-02-26 11:25 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-26  7:23 [PATCH] KVM: X86: Allow userspace to define the microcode version Wanpeng Li
2018-02-26  9:41 ` Borislav Petkov
2018-02-26 10:06   ` Wanpeng Li
2018-02-26 10:49     ` Borislav Petkov
2018-02-26 11:02       ` Wanpeng Li
2018-02-26 11:16         ` Borislav Petkov
2018-02-26 11:25           ` Wanpeng Li [this message]
2018-02-26 11:30             ` Borislav Petkov
2018-02-26 11:37               ` Wanpeng Li
2018-02-26 11:44                 ` Borislav Petkov
2018-02-26 11:52                   ` Wanpeng Li
2018-02-26 11:54                   ` Paolo Bonzini
2018-02-26 12:15                     ` Borislav Petkov
2018-02-26 12:16                       ` Paolo Bonzini
2018-02-26 12:18                         ` Paolo Bonzini
2018-02-26 12:22                           ` Borislav Petkov
2018-02-26 12:41                             ` Paolo Bonzini
2018-02-26 13:05                               ` Borislav Petkov
2018-02-26 14:39                               ` Konrad Rzeszutek Wilk
2018-02-26 14:46                                 ` Paolo Bonzini
2018-02-26 19:37                                 ` Borislav Petkov
2018-02-26 20:51                                   ` Konrad Rzeszutek Wilk
2018-02-26 21:30                                     ` Konrad Rzeszutek Wilk
2018-02-27  8:33                                       ` Paolo Bonzini
2018-03-08  9:24                                       ` [tip:x86/pti] x86/spectre_v2: Don't check microcode versions when running under hypervisors tip-bot for Konrad Rzeszutek Wilk
2018-04-17 10:40                               ` [PATCH] KVM: X86: Allow userspace to define the microcode version Wanpeng Li
2018-04-17 20:24                                 ` Eduardo Habkost
2018-04-18  3:24                                   ` Wanpeng Li
2018-04-18  9:03                                     ` Eduardo Habkost
2018-04-18 10:36                                       ` Paolo Bonzini
2018-04-23 12:58                                         ` Borislav Petkov
2018-04-23 13:08                                           ` Eduardo Habkost
2018-04-23 13:23                                             ` Borislav Petkov
2018-04-23 16:03                                           ` Paolo Bonzini
2018-04-24  2:59                                         ` Wanpeng Li
2018-04-24  3:14                                           ` Konrad Rzeszutek Wilk
2018-04-24  5:09                                             ` Paolo Bonzini
2018-04-24 13:44                                               ` Konrad Rzeszutek Wilk
2018-04-24  2:56                               ` Wanpeng Li
2018-02-26 11:47       ` Paolo Bonzini
2018-02-26 12:20         ` Borislav Petkov
2018-02-26  9:26 Liran Alon
2018-02-26 10:08 ` Wanpeng Li

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