From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A3ABC6778D for ; Tue, 11 Sep 2018 13:55:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAC4A2087F for ; Tue, 11 Sep 2018 13:55:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAC4A2087F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727778AbeIKSyu (ORCPT ); Tue, 11 Sep 2018 14:54:50 -0400 Received: from mx2.suse.de ([195.135.220.15]:48928 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726985AbeIKSyu (ORCPT ); Tue, 11 Sep 2018 14:54:50 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 088A6AF64; Tue, 11 Sep 2018 13:55:22 +0000 (UTC) Date: Tue, 11 Sep 2018 15:55:19 +0200 From: Borislav Petkov To: Paolo Bonzini Cc: Brijesh Singh , Sean Christopherson , x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Tom Lendacky , Thomas Gleixner , "H. Peter Anvin" , Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active Message-ID: <20180911135519.GI11418@zn.tnic> References: <1536586152.11460.40.camel@intel.com> <097eb5f5-2cd9-8b08-32c5-d90c8e0cbb6d@amd.com> <1536593297.11460.72.camel@intel.com> <11618b8b-4d1f-9307-35f0-3c0f0fc856ca@amd.com> <20180910164851.GC20286@zn.tnic> <3b8b4c9c-b0f6-1e08-3d26-0e146cd7189e@redhat.com> <20180911100142.GA11418@zn.tnic> <554c6fb5-0de4-5415-9970-0d09325d718b@redhat.com> <20180911102504.GC11418@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 11, 2018 at 01:07:06PM +0200, Paolo Bonzini wrote: > If the host TSCs are unsynchronized then yes, that's what happens. And > you can do live migration from synchronized to unsynchronized. Which brings us back to my original question: why would we *ever* want to support unsynchronized TSCs in a guest? Such machines are a real abomination for baremetal - it doesn't make *any* sense to me to have that in guests too, if it can be helped... -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --