From nobody Thu Apr 9 04:41:33 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 E26C2C433FE for ; Wed, 2 Nov 2022 19:30:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230304AbiKBTaa (ORCPT ); Wed, 2 Nov 2022 15:30:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229640AbiKBTaZ (ORCPT ); Wed, 2 Nov 2022 15:30:25 -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 2B42565CA for ; Wed, 2 Nov 2022 12:30:25 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id v18-20020a637a12000000b0046ed84b94efso9853178pgc.6 for ; Wed, 02 Nov 2022 12:30:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=4mfNKilwFmWrqa2spYtO5Tj25NqUdCGG8fx/ELXfW3g=; b=hhK6C71gMmgCuhyKE25DVYTKUHSUUpT5xEYkm1oWFozn/GMGCDvp3A4t4RmXNVxaaV YWZdMzV2pCTe90Zn/na6/OD8hPoDn73YxV4ek+H8NFrId8pLGs9gB15H/I13eQBbfx03 Zq6aRH94hVD2SytAxjwfY+Ri/baAKSJ3od+LHlYlOX9tmS6OfREqelFSknh3W5pxgFBQ qh6aafaql1y7CMtxFYjFwYw+YXOq7TNxfstUffyK70SfuaA5n68E6m6wAQ3ojftVQnMk EbYETIW/CyYkeJyEUoUKENpYhHAVRBVMKCmzAJZQIkUpXXbjG7IGT+BspHKzZoRUyKbw QGWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=4mfNKilwFmWrqa2spYtO5Tj25NqUdCGG8fx/ELXfW3g=; b=FHCTqy5Y423x4/Bs1TpYn4Qvm5VH1day5Ann8VFKVCFIppWXGJIvlGZ+14jynWmhJM wTtIHFo9GjQD372v/J73iL9Sgz+0IqmFz7kfDTOZAf6z1EOTtFyKXSSTukMZhNiTMhEm zXIBjrPHysMrbe+0a5YFH4l0h7Q3Pa/mQw1Czpa0i4zWhn8+r/ElV7mg9mblbXvjvfDk P60rRe1m0xTRLFTFpLWAv7DjzWXVAQ/lVcaum7QOPSmaV7nGtk+lISmsls8eaJRJYj26 fTWSQKE7ui/krXsUGww2A3TtfZJs+3stQQ4igeeaJujxeSHFnC+fwKnTDdrgaq6zsSKt AlJg== X-Gm-Message-State: ACrzQf0cJFwwaBfEegudgG7mhai1DEs+5CXXnZjsATEvfoRdaQJ0J0Jx u0AFMCIEXug14mniuaxpeml1kfEvRB4WhcGjamV2M2U58IQFZ931QshxgzVggq6+vPBS1rI3on+ 53IcimlOE+TmKuumCNFje25egulWR+ypOR4MybkY86r7jMbJfcHwFoEdzI2952aE9xEA6dEqW X-Google-Smtp-Source: AMsMyM6Jl6QZZ8lvOVzndcSJfSzMoMifS9JXraVtV/8BvsFPPKWh2/05r04l+hviMGWLAssl3ix1QT/J950k X-Received: from sweer.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:e45]) (user=bgardon job=sendgmr) by 2002:aa7:9099:0:b0:56a:d3f0:a013 with SMTP id i25-20020aa79099000000b0056ad3f0a013mr26991991pfa.26.1667417424554; Wed, 02 Nov 2022 12:30:24 -0700 (PDT) Date: Wed, 2 Nov 2022 19:30:20 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog Message-ID: <20221102193020.1091939-1-bgardon@google.com> Subject: [PATCH] KVM: x86: Use SRCU to protect zap in __kvm_set_or_clear_apicv_inhibit From: Ben Gardon To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , David Matlack , Anish Ghulati , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kvm_zap_gfn_range must be called in an SRCU read-critical section, but there is no SRCU annotation in __kvm_set_or_clear_apicv_inhibit. Add the needed SRCU annotation. Tested: ran tools/testing/selftests/kvm/x86_64/debug_regs on a DBG build. This patch causes the suspicious RCU warning to disappear. Note that the warning is hit in __kvm_zap_rmaps, so kvm_memslots_have_rmaps must return true in order for this to repro (i.e. the TDP MMU must be off or nesting in use.) Fixes: 36222b117e36 ("KVM: x86: don't disable APICv memslot when inhibited") Signed-off-by: Ben Gardon Reported-by? IIRC this originated in a syzkaller report? --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cd9eb13e2ed7..6d853e5f683d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10091,7 +10091,10 @@ void __kvm_set_or_clear_apicv_inhibit(struct kvm *= kvm, kvm->arch.apicv_inhibit_reasons =3D new; if (new) { unsigned long gfn =3D gpa_to_gfn(APIC_DEFAULT_PHYS_BASE); + int idx =3D srcu_read_lock(&kvm->srcu); + kvm_zap_gfn_range(kvm, gfn, gfn+1); + srcu_read_unlock(&kvm->srcu, idx); } } else { kvm->arch.apicv_inhibit_reasons =3D new; --=20 2.38.1.431.g37b22c650d-goog