From nobody Mon Apr 6 20:11:03 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 EFC05ECAAA1 for ; Sat, 3 Sep 2022 00:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231617AbiICAYY (ORCPT ); Fri, 2 Sep 2022 20:24:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231464AbiICAXc (ORCPT ); Fri, 2 Sep 2022 20:23:32 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8AF73107C4D for ; Fri, 2 Sep 2022 17:23:28 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id k126-20020a253d84000000b0068bb342010dso2791035yba.1 for ; Fri, 02 Sep 2022 17:23:28 -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=hPKVqX/qKnbg4wtZZoqH1v9WwL48+nuyy8M1K1yFn+Q=; b=NCUtkesuJSiUM6spxe/b4OJyxwM4vl24hU8ZXa6374IknbrY5QqWmqKMebFz1qDW96 2n9Gepnfn4gmaDx383mdo1EsfgdC22ScVDQZJEvcGVyvbBDYhc0s1Z3YOVR+gjhh1Loo +sX/Ggp2y3ceBJIVtzuZYvEiRtvPLXUOgirVn4+/IFDCHZ6UlLd0QXF3AWoCUnXY8qNx 2vQXT+gyc/3XYYo14X9e8v+QEPdZRqM3ED89N68rdRs2gySaYeiS0/Tq05DkE5b4jBve VdGk5JR8FwmLqV18faUMvvbC/JIAhIyub67JqnML0SqMIA2F7cx8plclbpFUgcAhOhCh 22kg== 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=hPKVqX/qKnbg4wtZZoqH1v9WwL48+nuyy8M1K1yFn+Q=; b=zBTnHaEGhkiHTzsrqSpQQw0MvJN3dF7HkC7sDO/JiXkxfNrIaIqWduR7SiJF7ysRBQ MWPW4U1n3WDlXvLcY1mhjEGuliQeUx8MECQPrrrhxQYL6bYwjEfOdwVgCCfbnO3B8su3 OyrKbIta8sELZbnc5fgz4bVeWpPqnME/SFL6Rmckb6GpqoEtfllxkAq0zK3Sjy80Uwh+ 9KYm3xGq97UIY9hQ9oNVcYmyjkj3LvwoF5YDOTrAPzd4PVuMn3kQt92rX8hY/zMR7toK 1TJiGUpxDqGjvQCncV7W1dP3P9+RC6sS4d4Hdh7V1X0Wf3iLjdcMqVJ2YChx7Bn5rw5H D0PA== X-Gm-Message-State: ACgBeo2p31gm0jo4ornY3QLLje2qcK1kdkRRPD0xkNDh8PeSlaBH3iiH gPG6+xpD5dNIQqmhABNq4K2VrEE9rT8= X-Google-Smtp-Source: AA6agR4AaMlxF/lgiWVv9UUSOZdreD17ciJY/4ExZuNkD+3dtrVHtCNRS9VPhDGPrWRp8mglAoCyQWRhppU= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a81:8502:0:b0:340:a7fc:ddb2 with SMTP id v2-20020a818502000000b00340a7fcddb2mr31888545ywf.378.1662164608243; Fri, 02 Sep 2022 17:23:28 -0700 (PDT) Reply-To: Sean Christopherson Date: Sat, 3 Sep 2022 00:22:48 +0000 In-Reply-To: <20220903002254.2411750-1-seanjc@google.com> Mime-Version: 1.0 References: <20220903002254.2411750-1-seanjc@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220903002254.2411750-18-seanjc@google.com> Subject: [PATCH v2 17/23] 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, 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 13dadc96d9ac..042dcdf987d2 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1144,6 +1144,12 @@ enum kvm_apicv_inhibit { * inhibits, this is sticky for simplicity. */ 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 407e933eb073..4cebbdd3431b 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -364,6 +364,11 @@ void kvm_recalculate_apic_map(struct kvm *kvm) cluster[ldr] =3D apic; } out: + 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 3400046ad0b4..efb0632d7457 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -994,7 +994,8 @@ bool avic_check_apicv_inhibit_reasons(enum kvm_apicv_in= hibit reason) BIT(APICV_INHIBIT_REASON_SEV) | 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 2.37.2.789.g6183377224-goog