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 38094C64EC4 for ; Fri, 3 Mar 2023 21:23:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231519AbjCCVXc (ORCPT ); Fri, 3 Mar 2023 16:23:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231339AbjCCVXa (ORCPT ); Fri, 3 Mar 2023 16:23:30 -0500 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07552CC33 for ; Fri, 3 Mar 2023 13:23:30 -0800 (PST) Received: by mail-pj1-x1033.google.com with SMTP id qa18-20020a17090b4fd200b0023750b675f5so7468079pjb.3 for ; Fri, 03 Mar 2023 13:23:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1677878609; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=J13QPDCD8erOXLzAP87eHVLFoCiKXjrrledHT75DlE8=; b=mpAYCLzvihPhqmQf5R0abRG/qfPnWg50bmlf0Dwd+T7Kvl+XrjewYeCAVm21NTOE4Z OV0x4ZQbGveGseJvZKklQbcgKkBmVdgsrXycBggO3SMIEu5qFQTv9gZpp1f5cDz928Hr EqPa+anfhgNFsSyeXk8TpNQymp/5QpTA9x37YneDOZL29beD0AAn4+1DKKwLbFRTSw/K 0+H+IBejr/QcbpB3aHzutgfplnE65nWLo+dZkXPdzO/om33BfOQ6DrBYF2puuMyL+bcp mNbPwjNPpa+iTPuPFyVNj4tEGAMkUT5mZZhdxSxfEgietBHFJL/psq5YdOH62ULenLYi i1NQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677878609; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=J13QPDCD8erOXLzAP87eHVLFoCiKXjrrledHT75DlE8=; b=kAaPntK8bNwsOf1CjgKHQPN2E0udWiJ1CMt793AYwFnP0m6i925HXjIkxOoIL9uNM1 m/+cJmsfVB8kohtvyvUnD+wWPd2eU2BfTT5VZBSwTrZbAi1To66JIlahVp4/ccoDbvOt lUYpLsHthJzk7eMRQlVUmRtGjIFrpDsE7OKTyzfZzoXMqMQY+YsvIOhCZHxRMNKKrPx8 2worLLxlNyRuUyGIIxMocd3mRy50feNoXtgf9HZYrooRUNINBBrGlz+SLWvbri93vrqE dHa+Nei58bOk4liqMY9NCGtyrzC5sXPOUuSGCANH+vVEX/zjvXpuBGjSczxxsEU0IXVz DeWA== X-Gm-Message-State: AO0yUKWAjVtKLcj5CzMAF6+MPf9hkMK6jz6fQDsOzBbBBDjKsaLg038v GW/sk86cs+u9QoEQPjvORUTQhQ== X-Google-Smtp-Source: AK7set8wDlQmB+2LkMhcIApEDe7dX/+rc1CGwIPHnpf6/crOMMw35lb2DinfXiFQpaHrf0/DRwKjPA== X-Received: by 2002:a17:902:f54c:b0:19a:8304:21eb with SMTP id h12-20020a170902f54c00b0019a830421ebmr7698974plf.6.1677878609293; Fri, 03 Mar 2023 13:23:29 -0800 (PST) Received: from google.com (77.62.105.34.bc.googleusercontent.com. [34.105.62.77]) by smtp.gmail.com with ESMTPSA id e8-20020a170902cf4800b0019a96d3b456sm1962346plg.44.2023.03.03.13.23.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Mar 2023 13:23:28 -0800 (PST) Date: Fri, 3 Mar 2023 21:23:24 +0000 From: Mingwei Zhang To: Aaron Lewis Cc: kvm@vger.kernel.org, pbonzini@redhat.com, jmattson@google.com, seanjc@google.com Subject: Re: [PATCH v3 2/8] KVM: x86: Clear all supported MPX xfeatures if they are not all set Message-ID: References: <20230224223607.1580880-1-aaronlewis@google.com> <20230224223607.1580880-3-aaronlewis@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230224223607.1580880-3-aaronlewis@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Feb 24, 2023, Aaron Lewis wrote: > Be a good citizen and don't allow any of the supported MPX xfeatures[1] > to be set if they can't all be set. That way userspace or a guest > doesn't fail if it attempts to set them in XCR0. > > [1] CPUID.(EAX=0DH,ECX=0):EAX.BNDREGS[bit-3] > CPUID.(EAX=0DH,ECX=0):EAX.BNDCSR[bit-4] > > Suggested-by: Jim Mattson > Signed-off-by: Aaron Lewis > --- > arch/x86/kvm/cpuid.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index e1165c196970..b2e7407cd114 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -60,9 +60,22 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted) > return ret; > } > > +static u64 sanitize_xcr0(u64 xcr0) > +{ > + u64 mask; > + > + mask = XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR; > + if ((xcr0 & mask) != mask) > + xcr0 &= ~mask; > + > + return xcr0; > +} Is it better to put sanitize_xcr0() into the previous patch? If we do that, this one will be just adding purely the MPX related logic and thus cleaner I think. > + > u64 kvm_permitted_xcr0(void) > { > - return kvm_caps.supported_xcr0 & xstate_get_guest_group_perm(); > + u64 permitted_xcr0 = kvm_caps.supported_xcr0 & xstate_get_guest_group_perm(); > + > + return sanitize_xcr0(permitted_xcr0); > } > > /* > -- > 2.39.2.637.g21b0678d19-goog >