From nobody Mon Feb 9 04:14:26 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 7A36CC001DF for ; Fri, 21 Jul 2023 23:00:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231310AbjGUXAl (ORCPT ); Fri, 21 Jul 2023 19:00:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231179AbjGUXA1 (ORCPT ); Fri, 21 Jul 2023 19:00:27 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DD5E3A9E for ; Fri, 21 Jul 2023 16:00:22 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5704991ea05so25109677b3.1 for ; Fri, 21 Jul 2023 16:00:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689980421; x=1690585221; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=X/oIShHlu0RWHnSfFLoqzSAF9H1dCTHQouzdEN73lD8=; b=pwTqHKWTE0X3bdnmjOpODVldyzk1dIzpF7+/KwNuUcq64cH0kstCCEWs/DVZKzzEcQ UIYI4y3o0dgHuY00MGLBeSShDY9DK9C+Vfe4LhtztHr1nAl9wCZc6nU2bDk/liPtPPYx eAE7ePKu5VeqX1llGnUpHdkCH0Naz8m2VAO2fa1k9qT0yn88NXpzEGgopXRvGimnBP79 cCyS3p/HCCNaTaVR6tDiHh7Jk/rUY4F9H9aVkv+jM+VqiQSGK7B7d2bMKDH9A9eDIub9 sJnTzFf4aggrhXC+PkV0I/dQ1oj5ueL69wIDEM+TJnL9gSTW5M1DReAyvT+tQK2kt83X SGPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689980421; x=1690585221; 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:message-id :reply-to; bh=X/oIShHlu0RWHnSfFLoqzSAF9H1dCTHQouzdEN73lD8=; b=ja9kvnyLJpeaxO+fXqeZtICdVHs0WNUtMP8bhMDTulDHVA1DSJ5o4OjULmRsav62EM RKLBUBN4YdN3IqIxrKcJH7cSa2f+FeO1hH2EzvVjzeq/fq3hQOASyRWYFaJ5nTOhLXas rHDN2RCuvE7jrQsfaZWGPaG8+ZwvkppyN67qPvG0vi5a1LoScqnbCW66AXuBLgsIZnAV h6S+lCce45ADJopLbJz2emOEr8Zg5AU/0OCHWUY7s5lgB4uEFcd0HYzGcdKwtak0uZmv Dl0EycuTvRjnPR6j4p38OjfIKCzNZDFs5RqL0xDabGT8nbJkghoG+C3Lrn6+ZkuRggQR IcAw== X-Gm-Message-State: ABy/qLYJVhXLgFXm9OaQDfst2EgYJ87Zfp6Al5L2eGyazU8ai1iIKH3v mYJkv50Dx/r5qw8Y904HsMrWaZlEypg= X-Google-Smtp-Source: APBJJlGsBQocGngXBpfZzLx0ZDqWk+ySytms2F+SQYW02DzFelMXdLlIMGbRjWpoaeOJ0cRSsCRm8yAEIk0= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a81:ae18:0:b0:577:4540:905a with SMTP id m24-20020a81ae18000000b005774540905amr12452ywh.7.1689980421153; Fri, 21 Jul 2023 16:00:21 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 21 Jul 2023 16:00:03 -0700 In-Reply-To: <20230721230006.2337941-1-seanjc@google.com> Mime-Version: 1.0 References: <20230721230006.2337941-1-seanjc@google.com> X-Mailer: git-send-email 2.41.0.487.g6d72f3e995-goog Message-ID: <20230721230006.2337941-7-seanjc@google.com> Subject: [PATCH v2 6/9] KVM: x86/mmu: Replace MMU_DEBUG with proper KVM_PROVE_MMU Kconfig From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Mingwei Zhang , David Matlack , Jim Mattson Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace MMU_DEBUG, which requires manually modifying KVM to enable the macro, with a proper Kconfig, KVM_PROVE_MMU. Now that pgprintk() and rmap_printk() are gone, i.e. the macro guards only KVM_MMU_WARN_ON() and won't flood the kernel logs, enabling the option for debug kernels is both desirable and feasible. Signed-off-by: Sean Christopherson --- arch/x86/kvm/Kconfig | 13 +++++++++++++ arch/x86/kvm/mmu/mmu.c | 4 ++-- arch/x86/kvm/mmu/mmu_internal.h | 4 +--- 3 files changed, 16 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 89ca7f4c1464..4e5a282cc518 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -138,6 +138,19 @@ config KVM_XEN =20 If in doubt, say "N". =20 +config KVM_PROVE_MMU + bool "Prove KVM MMU correctness" + depends on DEBUG_KERNEL + depends on KVM + depends on EXPERT + help + Enables runtime assertions in KVM's MMU that are too costly to enable + in anything remotely resembling a production environment, e.g. this + gates code that verifies a to-be-freed page table doesn't have any + present SPTEs. + + If in doubt, say "N". + config KVM_EXTERNAL_WRITE_TRACKING bool =20 diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index eb6af9c4cf14..933e48a73a9a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1693,7 +1693,7 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn= _range *range) return young; } =20 -#ifdef MMU_DEBUG +#ifdef CONFIG_KVM_PROVE_MMU static int is_empty_shadow_page(u64 *spt) { u64 *pos; @@ -1707,7 +1707,7 @@ static int is_empty_shadow_page(u64 *spt) } return 1; } -#endif +#endif /* CONFIG_KVM_PROVE_MMU */ =20 /* * This value is the sum of all of the kvm instances's diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_interna= l.h index cfe925fefa68..40e74db6a7d5 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -6,9 +6,7 @@ #include #include =20 -#undef MMU_DEBUG - -#ifdef MMU_DEBUG +#ifdef CONFIG_KVM_PROVE_MMU #define KVM_MMU_WARN_ON(x) WARN_ON_ONCE(x) #else #define KVM_MMU_WARN_ON(x) do { } while (0) --=20 2.41.0.487.g6d72f3e995-goog