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 AA653C38145 for ; Sat, 3 Sep 2022 00:24:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231790AbiICAYI (ORCPT ); Fri, 2 Sep 2022 20:24:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231611AbiICAXl (ORCPT ); Fri, 2 Sep 2022 20:23:41 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59B3AF7B20 for ; Fri, 2 Sep 2022 17:23:34 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-340a4dcb403so27045227b3.22 for ; Fri, 02 Sep 2022 17:23:34 -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=mbHk1vkw63VQJwpK5v7OYSHF5DuBwhkzqDp695B1D9E=; b=Am/ejqk+FXEoTdqA6s2ljphu1EM0595EUQYpOwC6lvm+KgrWBOIESYOdvlI13rVCPZ Vyi+6UUz2mfrA2rVOJSNVOKI3qA+J8gMPcEaeBitIxso8rJXNGznyswNq1LAm/wsV10n MSKiH3Q0nAksWQ2VqG2wE58WzWg88snpUMaDHItO4Egu8fVBUhx5nNuxWMUliI6+jOiI MBPOk1DctspVhiTN9Nbz9xYS/nO7y+mw9NG6cE/zu2LF4j0nWjFPuKm29jlhEKJqdkqo qAORYwnGOGgK7alkjsAgIaJ28v1W1M0g1xa6oVtijvyRmMWxTm3jxfdwsyPJZHw7eyP9 BIYw== 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=mbHk1vkw63VQJwpK5v7OYSHF5DuBwhkzqDp695B1D9E=; b=OIFYPJF7EIQJt2W7rlJI0XJ+N/xgQNgE/8/O9LR6DzTkDRA1D3EzCFCcbM2vbGAvGd 9qDo7knLdShVYOsJ4xuYcqIXbpU23FLx9IxW3VqQjLrlrKt6USfz0ku+xVTqiBUM3hNr cmkAOCGMtaPfZMeh9lb6tp2+KDiCzHKPiKuWUlWz0t64g57opgTClFFrwlxbVeTqtggU Xt79xHPLazfjeU9ipigmlNXQ8n/gaZzfXeDGINB3AHIN3hzMPJSpi9jK29LvK8lciWuJ u+xIn7U27OJsyRogXL8PY/oFsSS2kSJExC8g5PGTawTzF/tKzPBEX1YDzM67Lfil91GF Px/A== X-Gm-Message-State: ACgBeo3oq23AFQQLiPDOz1BAon6hzT6wYZr+YkQVK3HWNDDBupGpsGOZ 4QYOQgQ/vNRj6LdS7DXAWK/B99Eu1ks= X-Google-Smtp-Source: AA6agR78lhCJtcYdGkURpNKpNyVQm/bS5YisWK7p8gjPFbOehg4PIXtAlB4cJGGV/ylcAYQsbRZCRdb2N2E= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a5b:7c6:0:b0:6a7:509e:f13e with SMTP id t6-20020a5b07c6000000b006a7509ef13emr1382020ybq.302.1662164613075; Fri, 02 Sep 2022 17:23:33 -0700 (PDT) Reply-To: Sean Christopherson Date: Sat, 3 Sep 2022 00:22:51 +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: <20220903002254.2411750-21-seanjc@google.com> Subject: [PATCH v2 20/23] KVM: SVM: Require logical ID to be power-of-2 for AVIC entry From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Suravee Suthikulpanit , Maxim Levitsky , Li RongQing Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Do not modify AVIC's logical ID table if the logical ID portion of the LDR is not a power-of-2, i.e. if the LDR has multiple bits set. Taking only the first bit means that KVM will fail to match MDAs that intersect with "higher" bits in the "ID" The "ID" acts as a bitmap, but is referred to as an ID because theres an implicit, unenforced "requirement" that software only set one bit. This edge case is arguably out-of-spec behavior, but KVM cleanly handles it in all other cases, e.g. the optimized logical map (and AVIC!) is also disabled in this scenario. Refactor the code to consolidate the checks, and so that the code looks more like avic_kick_target_vcpus_fast(). Fixes: 18f40c53e10f ("svm: Add VMEXIT handlers for AVIC") Cc: Suravee Suthikulpanit Cc: Maxim Levitsky Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/avic.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 894d0afd761b..e34b9baa9ee0 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -540,26 +540,26 @@ unsigned long avic_vcpu_get_apicv_inhibit_reasons(struct kvm_vcpu *vcpu) static u32 *avic_get_logical_id_entry(struct kvm_vcpu *vcpu, u32 ldr, bool flat) { struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm); - int index; u32 *logical_apic_id_table; - int dlid = GET_APIC_LOGICAL_ID(ldr); + u32 cluster, index; - if (!dlid) - return NULL; + ldr = GET_APIC_LOGICAL_ID(ldr); - if (flat) { /* flat */ - index = ffs(dlid) - 1; - if (index > 7) + if (flat) { + cluster = 0; + } else { + cluster = (ldr >> 4) << 2; + if (cluster >= 0xf) return NULL; - } else { /* cluster */ - int cluster = (dlid & 0xf0) >> 4; - int apic = ffs(dlid & 0x0f) - 1; - - if ((apic < 0) || (apic > 7) || - (cluster >= 0xf)) - return NULL; - index = (cluster << 2) + apic; + ldr &= 0xf; } + if (!ldr || !is_power_of_2(ldr)) + return NULL; + + index = __ffs(ldr); + if (WARN_ON_ONCE(index > 7)) + return NULL; + index += (cluster << 2); logical_apic_id_table = (u32 *) page_address(kvm_svm->avic_logical_id_table_page); -- 2.37.2.789.g6183377224-goog