From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753369AbeBZNIM (ORCPT ); Mon, 26 Feb 2018 08:08:12 -0500 Received: from mail.skyhub.de ([5.9.137.197]:56338 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170AbeBZNGO (ORCPT ); Mon, 26 Feb 2018 08:06:14 -0500 Date: Mon, 26 Feb 2018 14:05:54 +0100 From: Borislav Petkov To: Paolo Bonzini Cc: Wanpeng Li , LKML , kvm , Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH] KVM: X86: Allow userspace to define the microcode version Message-ID: <20180226130553.GI4377@pd.tnic> References: <20180226113000.GC4377@pd.tnic> <20180226114409.GD4377@pd.tnic> <46cecef2-b0fb-b0c2-bbf3-983328d52763@redhat.com> <20180226121509.GE4377@pd.tnic> <24cd527d-5287-f0be-ffe8-eab341bf1d94@redhat.com> <3866d359-0ef8-6a99-6254-84890be62b93@redhat.com> <20180226122205.GG4377@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 01:41:38PM +0100, Paolo Bonzini wrote: > More like "-cpu foo,ucode_rev=0xdeadbeef". But in practice what would > happen is one of the following: > > 1) "-cpu host" sets ucode_rev to the same value of the host, everyone > else leaves it to zero as is now. > > 2) Only Amazon uses this feature and we ignore it. :) I fear that that might get misused and we probably should consider some trivial range checking and each qemu cpu model would have a valid range or so. Or we should better do that in kvm_set_msr_common directly... although if we do it here, it would require kvm knowing about all those different microcode revisions and qemu cpu models sounds better... -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.