From patchwork Sat Oct 9 02:12:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12546907 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1128DC433EF for ; Sat, 9 Oct 2021 02:14:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFC7560FD7 for ; Sat, 9 Oct 2021 02:14:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244626AbhJICQ2 (ORCPT ); Fri, 8 Oct 2021 22:16:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244541AbhJICP4 (ORCPT ); Fri, 8 Oct 2021 22:15:56 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EFAAEC061777 for ; Fri, 8 Oct 2021 19:13:31 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 124-20020a251182000000b005a027223ed9so14953047ybr.13 for ; Fri, 08 Oct 2021 19:13:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=JkZfdKKKsnqnpAtGUC7eJv8NSTwENPUfH6MKqHK3m28=; b=qVLIqxee/wprC+4bjZNYJueP2zjkd+ggVBKmgUwNSOpnEV7X/9yGfblAJrRqdCWEih HkkaQsOOaOeL+/6gKeVGYHju8vK+HKNcdt3bTPsONepW8SXVyQdRvqfaAKZcB8+jVwae l3QyVEsfib1Ds5XSLDwK5fjGQZuWnnjDxgzphYDPgXfwssEpRJVHvOakRnpFdPD78q0R +0gwjhJzjz6GJsBbS0TZrWfFGUf6BV3+uE57g+PTVVc8UKWIe6wyeSoVcPpQNBbE7SiU oPp2V17b+NBHZjC8Iixu81AY6DPeXf4DpNjHUN5949xj5Ej8bfX8i2do7PuBJAHe/oBY ATyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=JkZfdKKKsnqnpAtGUC7eJv8NSTwENPUfH6MKqHK3m28=; b=k+8trO4M2dejg9C5R2CdBEUGHfVO/nQWl/f1oGxjhwv1Rm6HfRgXD5DpkZbk5yBT+1 xlY913bpGeqnDZLy/+oxU2XauO6u/IN2TF39J6LBycosMnbztZI9NnOHOkRXV2NZTW8T se1FJk0Fa5T9Xp7zOCiulrv1egkICj7QL23/o7lCudOkSVQLGE3PBHE13C+PYwRa6E1o MddVMtu/ZoFNHs/DUz+cf6uTBiWFJBodja4PBqIGQxAe66513pD+OVIFTZyqjsBrR+OE Y5tey7hsfR9AtEqaori6Y+GIOwaR/N434H7zCQ82c8hBGPBcgntdSPfA2gaT8WNdPUJ7 ljIA== X-Gm-Message-State: AOAM530vUMvbXg48fRDnFh+zrgPVoLo85Byxfc8GQqgo2PS6h6ZxnnVw C+AzahwrhEemY8FH/fWGNd1S1XHJf+A= X-Google-Smtp-Source: ABdhPJzgeMmRSEoifPybAsuoSY+JDjln6XTZNwptycydEyLK/6KcdeEb7uS4dZEit5L6yoPPTC+t8rdx1rg= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:e39b:6333:b001:cb]) (user=seanjc job=sendgmr) by 2002:a5b:d03:: with SMTP id y3mr7590634ybp.400.1633745611129; Fri, 08 Oct 2021 19:13:31 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 8 Oct 2021 19:12:13 -0700 In-Reply-To: <20211009021236.4122790-1-seanjc@google.com> Message-Id: <20211009021236.4122790-21-seanjc@google.com> Mime-Version: 1.0 References: <20211009021236.4122790-1-seanjc@google.com> X-Mailer: git-send-email 2.33.0.882.g93a45727a2-goog Subject: [PATCH v2 20/43] KVM: VMX: Skip Posted Interrupt updates if APICv is hard disabled From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , Atish Patra , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , Oliver Upton , Jing Zhang Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Explicitly skip posted interrupt updates if APICv is disabled in all of KVM, or if the guest doesn't have an in-kernel APIC. The PI descriptor is kept up-to-date if APICv is inhibited, e.g. so that re-enabling APICv doesn't require a bunch of updates, but neither the module param nor the APIC type can be changed on-the-fly. Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky --- arch/x86/kvm/vmx/posted_intr.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 3263056784f5..351666c41bbc 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -28,11 +28,14 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) unsigned int dest; /* - * In case of hot-plug or hot-unplug, we may have to undo - * vmx_vcpu_pi_put even if there is no assigned device. And we - * always keep PI.NDST up to date for simplicity: it makes the - * code easier, and CPU migration is not a fast path. + * To simplify hot-plug and dynamic toggling of APICv, keep PI.NDST and + * PI.SN up-to-date even if there is no assigned device or if APICv is + * deactivated due to a dynamic inhibit bit, e.g. for Hyper-V's SyncIC. */ + if (!enable_apicv || !lapic_in_kernel(vcpu)) + return; + + /* Nothing to do if PI.SN==0 and the vCPU isn't being migrated. */ if (!pi_test_sn(pi_desc) && vcpu->cpu == cpu) return;