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 X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41189C43333 for ; Thu, 18 Mar 2021 22:44:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BF7864F40 for ; Thu, 18 Mar 2021 22:44:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233281AbhCRWn6 (ORCPT ); Thu, 18 Mar 2021 18:43:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232529AbhCRWnX (ORCPT ); Thu, 18 Mar 2021 18:43:23 -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 3982AC06175F for ; Thu, 18 Mar 2021 15:43:23 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id a63so50322825yba.2 for ; Thu, 18 Mar 2021 15:43:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=1L+9lJpNp7J82u8N+nWZfaJrNB467GIkhUgouUBgX1A=; b=Ns4hn+Cm38G8KktGdmCcDEaDZhKu9bZZgQazz7PyEoR+V0VC0jn/T4UDFfOv0jp6cK HKTUehDXiabOIJEmov51KsVzGhfp2GKVr9zO7Gh12AeCKXtaqHYirkfljTEqjNjFY1EB lQorNY8gkhM135aIIyWOE1zq3YzkZo3i79CNPyyCPoQrTc09WZ5he3RHFGWiwY6xLqw/ 5TyfbMXEmatfms8d2T8yLBs/L1QkqPjCIMy+I1qSa7uQgtAWmEFUQmGGS7LV2N1Wu6M4 XtSDl3piXlaiss6qL2n0zIgMgcmjHfoSXQZJ/RozpsW4MWFp88oPn8NLesQBoVabmk8O BEpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=1L+9lJpNp7J82u8N+nWZfaJrNB467GIkhUgouUBgX1A=; b=oqzMejieFHoZOsCMEKAya+0hfljzTMtdLUKOL8Z7A7ab1ZXUe7pxPzz/LUWYXGTJDD 6eyO+2ne4JI844FM91pCMkzsaWkvGe+nFdLSp2lAu+J5yQ9vOWN9U5U81NIfpr6KC6uz 1zqw2p5BN3izjzrpMOXKxejawIL8n70jTS4O6Mni8AvbRVq7z/61ZprfMMF4uz9BebB4 bBww8OScggyntOnV3wVUDeoZCJOyBdomGUYUCKpckqPvlRl5ajfsNjkMBLI5wy+XtL6m 5iXHWfnyAH005FCcY2FTLpnxVONlfvDU8o2IsbNlj4Hnc3UY85ZscNS/H46orl/mYJAV NmGA== X-Gm-Message-State: AOAM533pEDK3+d8KeFH8l8B21NGHScPSWjIbMTwwXNYVyWHd18+40P+h 87FLzpp1E8SlHJheb1F0VVy/ri6DXNA= X-Google-Smtp-Source: ABdhPJwwTJRd0BuDJ+GgYU89A4UQxSdfhSeDOq9f7SOu95IyLgNBPSJ3LyU+VylpQ/EPLpXHWDXsGv+QqoE= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:25e0:6b8b:f878:23d1]) (user=seanjc job=sendgmr) by 2002:a25:accd:: with SMTP id x13mr2417534ybd.88.1616107402509; Thu, 18 Mar 2021 15:43:22 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 18 Mar 2021 15:43:10 -0700 In-Reply-To: <20210318224310.3274160-1-seanjc@google.com> Message-Id: <20210318224310.3274160-5-seanjc@google.com> Mime-Version: 1.0 References: <20210318224310.3274160-1-seanjc@google.com> X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog Subject: [PATCH v2 4/4] KVM: nVMX: Clean up x2APIC MSR handling for L2 From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Graf , Yuan Yao Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Clean up the x2APIC MSR bitmap intereption code for L2, which is the last holdout of open coded bitmap manipulations. Freshen up the SDM/PRM comment, rename the function to make it abundantly clear the funky behavior is x2APIC specific, and explain _why_ vmcs01's bitmap is ignored (the previous comment was flat out wrong for x2APIC behavior). No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/nested.c | 53 +++++++++++---------------------------- arch/x86/kvm/vmx/vmx.h | 8 ++++++ 2 files changed, 22 insertions(+), 39 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index aff41a432a56..49eeffb79823 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -476,44 +476,19 @@ static int nested_vmx_check_tpr_shadow_controls(struct kvm_vcpu *vcpu, } /* - * If a msr is allowed by L0, we should check whether it is allowed by L1. - * The corresponding bit will be cleared unless both of L0 and L1 allow it. + * For x2APIC MSRs, ignore the vmcs01 bitmap. L1 can enable x2APIC without L1 + * itself utilizing x2APIC. All MSRs were previously set to be intercepted, + * only the disable intercept case needs to be handled. */ -static void nested_vmx_disable_intercept_for_msr(unsigned long *msr_bitmap_l1, - unsigned long *msr_bitmap_nested, - u32 msr, int type) +static void nested_vmx_disable_intercept_for_x2apic_msr(unsigned long *msr_bitmap_l1, + unsigned long *msr_bitmap_l0, + u32 msr, int type) { - int f = sizeof(unsigned long); + if (type & MSR_TYPE_R && !vmx_test_msr_bitmap_read(msr_bitmap_l1, msr)) + vmx_clear_msr_bitmap_read(msr_bitmap_l0, msr); - /* - * See Intel PRM Vol. 3, 20.6.9 (MSR-Bitmap Address). Early manuals - * have the write-low and read-high bitmap offsets the wrong way round. - * We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff. - */ - if (msr <= 0x1fff) { - if (type & MSR_TYPE_R && - !test_bit(msr, msr_bitmap_l1 + 0x000 / f)) - /* read-low */ - __clear_bit(msr, msr_bitmap_nested + 0x000 / f); - - if (type & MSR_TYPE_W && - !test_bit(msr, msr_bitmap_l1 + 0x800 / f)) - /* write-low */ - __clear_bit(msr, msr_bitmap_nested + 0x800 / f); - - } else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) { - msr &= 0x1fff; - if (type & MSR_TYPE_R && - !test_bit(msr, msr_bitmap_l1 + 0x400 / f)) - /* read-high */ - __clear_bit(msr, msr_bitmap_nested + 0x400 / f); - - if (type & MSR_TYPE_W && - !test_bit(msr, msr_bitmap_l1 + 0xc00 / f)) - /* write-high */ - __clear_bit(msr, msr_bitmap_nested + 0xc00 / f); - - } + if (type & MSR_TYPE_W && !vmx_test_msr_bitmap_write(msr_bitmap_l1, msr)) + vmx_clear_msr_bitmap_write(msr_bitmap_l0, msr); } static inline void enable_x2apic_msr_intercepts(unsigned long *msr_bitmap) @@ -582,7 +557,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, /* * To keep the control flow simple, pay eight 8-byte writes (sixteen * 4-byte writes on 32-bit systems) up front to enable intercepts for - * the x2APIC MSR range and selectively disable them below. + * the x2APIC MSR range and selectively toggle those relevant to L2. */ enable_x2apic_msr_intercepts(msr_bitmap_l0); @@ -601,17 +576,17 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, } } - nested_vmx_disable_intercept_for_msr( + nested_vmx_disable_intercept_for_x2apic_msr( msr_bitmap_l1, msr_bitmap_l0, X2APIC_MSR(APIC_TASKPRI), MSR_TYPE_R | MSR_TYPE_W); if (nested_cpu_has_vid(vmcs12)) { - nested_vmx_disable_intercept_for_msr( + nested_vmx_disable_intercept_for_x2apic_msr( msr_bitmap_l1, msr_bitmap_l0, X2APIC_MSR(APIC_EOI), MSR_TYPE_W); - nested_vmx_disable_intercept_for_msr( + nested_vmx_disable_intercept_for_x2apic_msr( msr_bitmap_l1, msr_bitmap_l0, X2APIC_MSR(APIC_SELF_IPI), MSR_TYPE_W); diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 42c25fc79427..03ab9ccd95d2 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -393,6 +393,14 @@ void vmx_set_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type, bool value); void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu); +/* + * Note, early Intel manuals have the write-low and read-high bitmap offsets + * the wrong way round. The bitmaps control MSRs 0x00000000-0x00001fff and + * 0xc0000000-0xc0001fff. The former (low) uses bytes 0-0x3ff for reads and + * 0x800-0xbff for writes. The latter (high) uses 0x400-0x7ff for reads and + * 0xc00-0xfff for writes. MSRs not covered by either of the ranges always + * VM-Exit. + */ #define __BUILD_VMX_MSR_BITMAP_HELPER(rtype, action, bitop, access, base) \ static inline rtype vmx_##action##_msr_bitmap_##access(unsigned long *bitmap, \ u32 msr) \ -- 2.31.0.rc2.261.g7f71774620-goog