From nobody Thu Apr 2 21:30:44 2026 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 88D1BC54EE9 for ; Tue, 20 Sep 2022 23:33:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231598AbiITXdr (ORCPT ); Tue, 20 Sep 2022 19:33:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231437AbiITXcp (ORCPT ); Tue, 20 Sep 2022 19:32:45 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A06178BD7 for ; Tue, 20 Sep 2022 16:32:15 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id w1-20020a63d741000000b0042c254a4ccdso2461622pgi.15 for ; Tue, 20 Sep 2022 16:32:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date; bh=vsB2EXY9q1cnnbhcdlWF5rsjKI75izh6EDAPIDxJ6Xw=; b=bAJ+timLm9bQ/xjMToD+8hIRKEhT5G4/eow6iqd/oCrUU1Th682zYJLp9CmuweIK+h FHkCiCip6gMjjAmhl2K7/108Tk2/avuol43nXGBGrDH2Chjck4ekNFs9GbOcLBpGr+CN pxIPOdfDGkQBLyU/QwhsjLPiFmhH4f5M5EHNq4C+yjFn8xRBjIXPfL9XCbGAsTW57WEt AmO2zcCd6MtrTPUjfRxCOPtLhmCiFIugUbtHd9bSDMQvj2NzYZDDtNQU/YXynKdm17eb iV2aaTyeIA5FUasRIARSCaYhFE2Zbe1Qp4qwdFp6/BuDFKcW762bIk9Pfg8vFfbu7l5k WdCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date; bh=vsB2EXY9q1cnnbhcdlWF5rsjKI75izh6EDAPIDxJ6Xw=; b=Cs32pYA5BVmRqAk7RXN3j/AXf2jP9jW1wWRFJc7fjMbKVHDM/G4rV+i75X1yONDNIK Frp7u73Uaaket/jDBcNX+jCi5YGcRf9i8MIu/5S5yIIW6Tpj1SfmDiCsnS3FvBSaWaeL 46itxtxQQOBxd72PnAMkwbkquPg0J7GcHxa4y/w7rkOy/SFob1R1Xh6SMQwMa5qHppPD fxQwcn8ePTYSUNXd4Yqpz6kAP2Y7xK0EKhqIda61oIjjbs5ql6PsgAxKQpdJePqbd8lT J8rhZagI/p9M/RIRWHLnA48+86TRtoQ0QQM7046jstdeU0SnNKGBDFnToHR1Meppae0u xMBQ== X-Gm-Message-State: ACrzQf3D5hGItSoN8USy9cZMYGsc2VycOgTggH/1cMngRp4uQFHIFU3J 48Bev1aYpLZZ17mpY3dHQgQ3Ml6buJU= X-Google-Smtp-Source: AMsMyM6gwxE+9V1iUOnFoB3jGYRREssKhetvh4T5MdU4y0U/leMrubqM0MU6KrMORuQPVeU27W//QbTQbSU= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90b:10a:b0:200:2849:235f with SMTP id p10-20020a17090b010a00b002002849235fmr524276pjz.1.1663716733523; Tue, 20 Sep 2022 16:32:13 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 20 Sep 2022 23:31:28 +0000 In-Reply-To: <20220920233134.940511-1-seanjc@google.com> Mime-Version: 1.0 References: <20220920233134.940511-1-seanjc@google.com> X-Mailer: git-send-email 2.37.3.968.ga6b4b080e4-goog Message-ID: <20220920233134.940511-23-seanjc@google.com> Subject: [PATCH v3 22/28] KVM: SVM: Inhibit AVIC if vCPUs are aliased in logical mode From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Alejandro Jimenez , Suravee Suthikulpanit , Maxim Levitsky , Li RongQing Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Inhibit SVM's AVIC if multiple vCPUs are aliased to the same logical ID. Architecturally, all CPUs whose logical ID matches the MDA are supposed to receive the interrupt; overwriting existing entries in AVIC's logical=3D>physical map can result in missed IPIs. Fixes: 18f40c53e10f ("svm: Add VMEXIT handlers for AVIC") Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 6 ++++++ arch/x86/kvm/lapic.c | 5 +++++ arch/x86/kvm/svm/avic.c | 3 ++- 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index 594674eefe59..32c0bca052e3 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1152,6 +1152,12 @@ enum kvm_apicv_inhibit { * APIC base. For simplicity, this is sticky. */ APICV_INHIBIT_REASON_X2APIC, + + /* + * AVIC is disabled because not all vCPUs with a valid LDR have a 1:1 + * mapping between logical ID and vCPU. + */ + APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED, }; =20 struct kvm_arch { diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 4db162b1f0b1..804d529d9bfb 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -391,6 +391,11 @@ void kvm_recalculate_apic_map(struct kvm *kvm) else kvm_clear_apicv_inhibit(kvm, APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED); =20 + if (!new || new->logical_mode =3D=3D KVM_APIC_MODE_MAP_DISABLED) + kvm_set_apicv_inhibit(kvm, APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED); + else + kvm_clear_apicv_inhibit(kvm, APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED); + old =3D rcu_dereference_protected(kvm->arch.apic_map, lockdep_is_held(&kvm->arch.apic_map_lock)); rcu_assign_pointer(kvm->arch.apic_map, new); diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 2908adc79ea6..27d5abc15a91 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -968,7 +968,8 @@ bool avic_check_apicv_inhibit_reasons(enum kvm_apicv_in= hibit reason) BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) | BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) | BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED) | - BIT(APICV_INHIBIT_REASON_X2APIC); + BIT(APICV_INHIBIT_REASON_X2APIC) | + BIT(APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED); =20 return supported & BIT(reason); } --=20 2.37.3.968.ga6b4b080e4-goog