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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 0576AECDE5F for ; Mon, 23 Jul 2018 06:09:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACE1120846 for ; Mon, 23 Jul 2018 06:09:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACE1120846 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S2387834AbeGWHI7 (ORCPT ); Mon, 23 Jul 2018 03:08:59 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50888 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728188AbeGWHI6 (ORCPT ); Mon, 23 Jul 2018 03:08:58 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DA5118790F; Mon, 23 Jul 2018 06:09:24 +0000 (UTC) Received: from [10.36.116.129] (ovpn-116-129.ams2.redhat.com [10.36.116.129]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1FF462156897; Mon, 23 Jul 2018 06:09:22 +0000 (UTC) Subject: Re: [PATCH v4 4/6] KVM: X86: Implement PV IPIs send hypercall To: Wanpeng Li Cc: LKML , kvm , Radim Krcmar , Wanpeng Li , Vitaly Kuznetsov References: <1532104133-15777-1-git-send-email-wanpengli@tencent.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; prefer-encrypt=mutual; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Mon, 23 Jul 2018 06:09:24 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Mon, 23 Jul 2018 06:09:24 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'pbonzini@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/07/2018 08:00, Wanpeng Li wrote: > On Mon, 23 Jul 2018 at 13:52, Paolo Bonzini wrote: >> >> On 20/07/2018 18:28, Wanpeng Li wrote: >>> +a0: ipi_bitmap low 64 bits >>> +a1: ipi_bitmap high 64 bits >>> +a2: the lowest APIC ID in bitmap >>> +a3: APIC ICR >>> + >>> +The hypercall lets a guest send multicast IPIs at most can handle >>> +128 vCPUs per hypercall on 64-bit machines and 64 vCPUs per hypercall >>> +on 32-bit machines. >>> + >>> +Returns 0 if successfully delivery the IPIs and 1 if discarded. >> >> This description does not mention what happens in 32-bit mode. > > Will do in next version. > >> >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index 2b812b3..016c7e2 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -6691,6 +6691,41 @@ static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid) >>> kvm_irq_delivery_to_apic(kvm, NULL, &lapic_irq, NULL); >>> } >>> >>> +/* >>> + * Return 0 if successfully added and 1 if discarded. >>> + */ >>> +static int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low, >>> + unsigned long ipi_bitmap_high, int min, int vector, int op_64_bit) >>> +{ >>> + int i; >>> + struct kvm_apic_map *map; >>> + struct kvm_vcpu *vcpu; >>> + struct kvm_lapic_irq irq = { >>> + .delivery_mode = APIC_DM_FIXED, >>> + .vector = vector, >>> + }; >>> + >>> + rcu_read_lock(); >>> + map = rcu_dereference(kvm->arch.apic_map); >>> + >>> + for_each_set_bit(i, &ipi_bitmap_low, BITS_PER_LONG) { >>> + vcpu = map->phys_map[min + i]->vcpu; >>> + if (!kvm_apic_set_irq(vcpu, &irq, NULL)) >>> + return 1; >>> + } >>> + >>> + if (op_64_bit) { >>> + for_each_set_bit(i, &ipi_bitmap_high, BITS_PER_LONG) { >>> + vcpu = map->phys_map[min + i + BITS_PER_LONG]->vcpu; >>> + if (!kvm_apic_set_irq(vcpu, &irq, NULL)) >>> + return 1; >>> + } >>> + } >> >> The second loop processes the second argument, and it should always run, >> even in 32-bit mode. However, the phys_map index should be min + i + 32 >> in 32-bit mode and min + i + 64 in 64-bit mode. (Using BITS_PER_LONG in >> the for_each_set_bit length is not a bug instead; you could write it >> explicitly as 32 in 32-bit mode, and 64 in 64-bit mode, but I think it's >> a little bit more efficient if it's constant). > > Good catch, below should fix it. > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index c9dbc2c..c118040 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6701,6 +6701,7 @@ static int kvm_pv_send_ipi(struct kvm *kvm, > unsigned long ipi_bitmap_low, > struct kvm_apic_map *map; > struct kvm_vcpu *vcpu; > struct kvm_lapic_irq irq = {0}; > + int cluster_size = op_64_bit ? 64 : 32; > > switch (icr & APIC_VECTOR_MASK) { > default: > @@ -6714,18 +6715,16 @@ static int kvm_pv_send_ipi(struct kvm *kvm, > unsigned long ipi_bitmap_low, > rcu_read_lock(); > map = rcu_dereference(kvm->arch.apic_map); > > - for_each_set_bit(i, &ipi_bitmap_low, BITS_PER_LONG) { > + for_each_set_bit(i, &ipi_bitmap_low, cluster_size) { > vcpu = map->phys_map[min + i]->vcpu; > if (!kvm_apic_set_irq(vcpu, &irq, NULL)) > return 1; > } > > - if (op_64_bit) { > - for_each_set_bit(i, &ipi_bitmap_high, BITS_PER_LONG) { > - vcpu = map->phys_map[min + i + BITS_PER_LONG]->vcpu; > - if (!kvm_apic_set_irq(vcpu, &irq, NULL)) > - return 1; > - } > + for_each_set_bit(i, &ipi_bitmap_high, cluster_size) { > + vcpu = map->phys_map[min + i + cluster_size]->vcpu; > + if (!kvm_apic_set_irq(vcpu, &irq, NULL)) > + return 1; > } > > rcu_read_unlock(); > Yes, that should work. Thanks! Paolo