From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751384AbaLRPKc (ORCPT ); Thu, 18 Dec 2014 10:10:32 -0500 Received: from mga11.intel.com ([192.55.52.93]:29033 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751068AbaLRPKb convert rfc822-to-8bit (ORCPT ); Thu, 18 Dec 2014 10:10:31 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,601,1413270000"; d="scan'208";a="639750919" From: "Zhang, Yang Z" To: Paolo Bonzini , "kvm@vger.kernel.org" CC: "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" Subject: RE: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set Thread-Topic: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set Thread-Index: AQHQGqESVjGwCGGcx0GfXydnqyBdC5yVc2Hg Date: Thu, 18 Dec 2014 15:09:48 +0000 Message-ID: References: <1418397300-10870-1-git-send-email-feng.wu@intel.com> <1418397300-10870-26-git-send-email-feng.wu@intel.com> <5491C0A2.7040503@redhat.com> <5492926E.8070207@redhat.com> In-Reply-To: <5492926E.8070207@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo Bonzini wrote on 2014-12-18: > > > On 18/12/2014 04:14, Wu, Feng wrote: >> >> >> linux-kernel-owner@vger.kernel.org wrote on mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Paolo: >>> x86@kernel.org; Gleb Natapov; Paolo Bonzini; dwmw2@infradead.org; >>> joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org; Alex Williamson; >>> joro-zLv9SwRftAIdnm+Jiang >>> Liu >>> Cc: iommu@lists.linux-foundation.org; >>> linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; KVM list; >>> Eric Auger >>> Subject: Re: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is >>> set >>> >>> >>> >>> On 12/12/2014 16:14, Feng Wu wrote: >>>> Currently, we don't support urgent interrupt, all interrupts are >>>> recognized as non-urgent interrupt, so we cannot send >>>> posted-interrupt when 'SN' is set. >>> >>> Can this happen? If the vcpu is in guest mode, it cannot have been >>> scheduled out, and that's the only case when SN is set. >>> >>> Paolo >> >> Currently, the only place where SN is set is vCPU is preempted and If the vCPU is preempted, shouldn't the subsequent be ignored? What happens if a PI is occurs when vCPU is preempted? >> waiting for the next scheduling in the runqueue. But I am not sure >> whether we need to set SN for other purpose in future. Adding SN >> checking here is just to follow the Spec. non-urgent interrupts are >> suppressed > when SN is set. > > I would change that to a WARN_ON_ONCE then. Best regards, Yang