Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752132AbbHMHby (ORCPT ); Thu, 13 Aug 2015 03:31:54 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:36382 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751233AbbHMHbx (ORCPT ); Thu, 13 Aug 2015 03:31:53 -0400 Subject: Re: [PATCH 1/2] KVM: x86: set TMR when the interrupt is accepted To: "Zhang, Yang Z" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" References: <1438177055-26764-1-git-send-email-pbonzini@redhat.com> <1438177055-26764-2-git-send-email-pbonzini@redhat.com> <55BB2B62.1030605@redhat.com> <55BF21E1.5030100@redhat.com> <55BF48A4.5030409@redhat.com> <55C062EC.20006@redhat.com> Cc: "alex.williamson@redhat.com" , "srutherford@intel.com" , "Gudimetla, Giridhar Kumar" , "Nakajima, Jun" From: Paolo Bonzini Message-ID: <55CC47E4.5090200@redhat.com> Date: Thu, 13 Aug 2015 09:31:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 824 Lines: 22 On 13/08/2015 08:35, Zhang, Yang Z wrote: >> You may be right. It is safe if no future hardware plans to use >> it. Let me check with our hardware team to see whether it will be >> used or not in future. > > After checking with Jun, there is no guarantee that the guest running > on another CPU will operate properly if hypervisor modify the vTMR > from another CPU. So the hypervisor should not to do it. I guess I can cause a vmexit on level-triggered interrupts, it's not a big deal, but no weasel words, please. What's going to break, and where is it documented? Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/