From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933094AbcCIQBF (ORCPT ); Wed, 9 Mar 2016 11:01:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37934 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753634AbcCIQA5 (ORCPT ); Wed, 9 Mar 2016 11:00:57 -0500 Date: Wed, 9 Mar 2016 17:00:50 +0100 From: Radim =?utf-8?B?S3LEjW3DocWZ?= To: Paolo Bonzini Cc: Suravee Suthikulpanit , joro@8bytes.org, bp@alien8.de, gleb@kernel.org, alex.williamson@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, wei@redhat.com, sherry.hurwitz@amd.com Subject: Re: [PART1 RFC v2 06/10] svm: Add interrupt injection via AVIC Message-ID: <20160309160050.GB31328@potion.brq.redhat.com> References: <1457124368-2025-1-git-send-email-Suravee.Suthikulpanit@amd.com> <1457124368-2025-7-git-send-email-Suravee.Suthikulpanit@amd.com> <56DD9FF5.7010201@redhat.com> <20160308215424.GA31328@potion.brq.redhat.com> <56E004A2.70702@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <56E004A2.70702@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2016-03-09 12:10+0100, Paolo Bonzini: > On 08/03/2016 22:54, Radim Krčmář wrote: >> 2016-03-07 16:36+0100, Paolo Bonzini: >>> On 04/03/2016 21:46, Suravee Suthikulpanit wrote: >>>> +static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec) >>>> +{ >>>> + struct vcpu_svm *svm = to_svm(vcpu); >>>> + >>>> + kvm_lapic_set_vector(vec, avic_get_bk_page_entry(svm, APIC_IRR)); >> >> (I think that smp_mb here would make sense, even though we're fine now >> thanks to re-checking vcpu->mode in kvm_vcpu_kick. > > Right, though only a smp_mb__after_atomic() is required (which is a > compiler barrier). It is similarly required in vmx. True, kvm_lapic_set_vector uses a lock prefix. (I thought it behaves like atomic_set, which would require MFENCE for correct ordering here ... I don't like smp_mb__after_atomic much because of the discrepancy on some atomic operations.) > Offtopic remark, kvm_make_request() and kvm_check_request() should > probably have a smp_wmb() and a smp_rmb(). Yeah, noted.