From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752742AbeBZLQ5 (ORCPT ); Mon, 26 Feb 2018 06:16:57 -0500 Received: from mail.skyhub.de ([5.9.137.197]:51904 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752157AbeBZLQw (ORCPT ); Mon, 26 Feb 2018 06:16:52 -0500 Date: Mon, 26 Feb 2018 12:16:30 +0100 From: Borislav Petkov To: Wanpeng Li Cc: LKML , kvm , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH] KVM: X86: Allow userspace to define the microcode version Message-ID: <20180226111630.GB4377@pd.tnic> References: <1519629838-4898-1-git-send-email-wanpengli@tencent.com> <20180226094148.GA15539@pd.tnic> <20180226104921.GA4377@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? > https://lkml.org/lkml/2017/12/9/29 The original discussion explain in > more details. My argument stands: exposing microcode revisions to guests is the wrong approach. Instead, the kernel should not look at microcode revisions if it runs virtualized. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.