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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9CF7C433FE for ; Fri, 11 Feb 2022 11:01:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349295AbiBKLBY (ORCPT ); Fri, 11 Feb 2022 06:01:24 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:59882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349238AbiBKLBW (ORCPT ); Fri, 11 Feb 2022 06:01:22 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7E61FD5F for ; Fri, 11 Feb 2022 03:01:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644577280; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=26enP3RyEfUVYXxVtyOpkulynQz+0id22F0IbI7Q6zQ=; b=bTfVB2AJNYHGoEF15dzECZQMzwmP9hfvi+d7/sgRL+CugfESUQr67fBcGGcr4O+QW/Noi5 uuolKAF5eqbYIP4UA9fWobD3Nj5dDhLszM70KldSxzQj7Uxu3ZB7jOM1MY4fmE5CfElDok UczsljG5MyGGo86baxIGOdpxkqNkDbw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-20-DzU0gAk0OymCK5gEpMFk9A-1; Fri, 11 Feb 2022 06:01:19 -0500 X-MC-Unique: DzU0gAk0OymCK5gEpMFk9A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 863C8814245; Fri, 11 Feb 2022 11:01:18 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 36F4C7BB6A; Fri, 11 Feb 2022 11:01:18 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: mlevitsk@redhat.com Subject: [PATCH 1/3] KVM: SVM: extract avic_ring_doorbell Date: Fri, 11 Feb 2022 06:01:15 -0500 Message-Id: <20220211110117.2764381-2-pbonzini@redhat.com> In-Reply-To: <20220211110117.2764381-1-pbonzini@redhat.com> References: <20220211110117.2764381-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Maxim Levitsky The check on the current CPU adds an extra level of indentation to svm_deliver_avic_intr and conflates documentation on what happens if the vCPU exits (of interest to svm_deliver_avic_intr) and migrates (only of interest to avic_ring_doorbell, which calls get/put_cpu()). Extract the wrmsr to a separate function and rewrite the comment in svm_deliver_avic_intr(). Co-developed-by: Paolo Bonzini Signed-off-by: Paolo Bonzini Signed-off-by: Maxim Levitsky Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 3f9b48732aea..4d1baf5c8f6a 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -269,6 +269,24 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu) return 0; } + +static void avic_ring_doorbell(struct kvm_vcpu *vcpu) +{ + /* + * Note, the vCPU could get migrated to a different pCPU at any + * point, which could result in signalling the wrong/previous + * pCPU. But if that happens the vCPU is guaranteed to do a + * VMRUN (after being migrated) and thus will process pending + * interrupts, i.e. a doorbell is not needed (and the spurious + * one is harmless). + */ + int cpu = READ_ONCE(vcpu->cpu); + + if (cpu != get_cpu()) + wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu)); + put_cpu(); +} + static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source, u32 icrl, u32 icrh) { @@ -669,19 +687,12 @@ int svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec) * automatically process AVIC interrupts at VMRUN. */ if (vcpu->mode == IN_GUEST_MODE) { - int cpu = READ_ONCE(vcpu->cpu); - /* - * Note, the vCPU could get migrated to a different pCPU at any - * point, which could result in signalling the wrong/previous - * pCPU. But if that happens the vCPU is guaranteed to do a - * VMRUN (after being migrated) and thus will process pending - * interrupts, i.e. a doorbell is not needed (and the spurious - * one is harmless). + * Signal the doorbell to tell hardware to inject the IRQ if the vCPU + * is in the guest. If the vCPU is not in the guest, hardware will + * automatically process AVIC interrupts at VMRUN. */ - if (cpu != get_cpu()) - wrmsrl(MSR_AMD64_SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpu)); - put_cpu(); + avic_ring_doorbell(vcpu); } else { /* * Wake the vCPU if it was blocking. KVM will then detect the -- 2.31.1