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=ham 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 0C4B5C48BE8 for ; Fri, 18 Jun 2021 21:47:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9FA161279 for ; Fri, 18 Jun 2021 21:47:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234676AbhFRVtN (ORCPT ); Fri, 18 Jun 2021 17:49:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234662AbhFRVtM (ORCPT ); Fri, 18 Jun 2021 17:49:12 -0400 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DEBCC06175F for ; Fri, 18 Jun 2021 14:47:02 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id d12-20020ac8668c0000b0290246e35b30f8so5908549qtp.21 for ; Fri, 18 Jun 2021 14:47:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=reply-to:date:message-id:mime-version:subject:from:to:cc; bh=229mnDm6P0b0PXS4C471S6HQyDxSv4bvPmDKNuB7k40=; b=aKAShhDSlz34FFmsBMzsWaopNkOIayd5iqC4WyI4nw7EHmyz6gT3UNsYYkA71XKeGs HYe325z0spWnArGr1ct0HlvaPXJayYmoz3xEBsLNR2pYu9W5ytLUi3GbsyqNYhhg8FCD Kb0ZSi/hLFCt9lXQLZwNJrIiFthTWhjtN8xLE6U8McLD2HTX3ZnPVJOlc6yt4/ltMrLJ pxCJi0HXJEepqSOcKixEIappwWajaMiojKxb6YUNU6JblgSinSZlx5p1CKyHSE+IrT0d VmEnviQfI4knT2PFN30QysB8oRcrx//+0BzI2VxVhymP1HfHRYD6i2XTIeuYzik0eK+B fpVw== 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:message-id:mime-version:subject :from:to:cc; bh=229mnDm6P0b0PXS4C471S6HQyDxSv4bvPmDKNuB7k40=; b=feTlrQEjGqmqWMcnJfaekjaTyRKni+bfEJ22f2HEBJquU1Uv2DadArfvccizadeNVJ CYj9MQ3ePHSe+MWajn8mOzyHb4ccR4j41OdbN+Iv9CC2N85ilQyV7k80d3I9R+6kDC2P 7zHLxGp9XdWgXJmFQp3ZaG6c5l6qUg+adQzeyrle4NKlYVUdVmMZA6mk1B7jzOjaf/7K jZdywaMCGuwGD51+rqysEa6CQjC1C8YljiqOse3JQVPAKxWzc3f31s2YXT5uRtD3qkoP AqVVEcTLpZ9eQtBcJRPFGwAWa8bJGtUMDQJg5nymw1R++5zSoqunlz0jNwxbGRQCM/J8 Kv7w== X-Gm-Message-State: AOAM531g5EmZkIrJYWtY3C9NSf/8Kflh4TEPQebdwoK+/i/UyfDyB+At H4CLrf5EyFtwXytYnvqE5g5Q+egyx5c= X-Google-Smtp-Source: ABdhPJxZL8lxhONicplEpmwS8lyjiTsFH0Vv+IEk6+sMdK7gQPIj8pWgQOmqhB6KusakfNutUaK0t9NtoaI= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:d689:126c:66f2:8013]) (user=seanjc job=sendgmr) by 2002:a25:4048:: with SMTP id n69mr15751195yba.91.1624052821314; Fri, 18 Jun 2021 14:47:01 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 18 Jun 2021 14:46:58 -0700 Message-Id: <20210618214658.2700765-1-seanjc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.32.0.288.g62a8d224e6-goog Subject: [PATCH] KVM: nVMX: Dynamically compute max VMCS index for vmcs12 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Calculate the max VMCS index for vmcs12 by walking the array to find the actual max index. Hardcoding the index is prone to bitrot, and the calculation is only done on KVM bringup (albeit on every CPU, but there aren't _that_ many null entries in the array). Fixes: 3c0f99366e34 ("KVM: nVMX: Add a TSC multiplier field in VMCS12") Signed-off-by: Sean Christopherson --- Note, the vmx test in kvm-unit-tests will still fail using stock QEMU, as QEMU also hardcodes and overwrites the MSR. The test passes if I hack KVM to ignore userspace (it was easier than rebuilding QEMU). arch/x86/kvm/vmx/nested.c | 37 +++++++++++++++++++++++++++++++++++-- arch/x86/kvm/vmx/vmcs.h | 8 ++++++++ arch/x86/kvm/vmx/vmcs12.h | 6 ------ 3 files changed, 43 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index b531e08a095b..183fd9d62fc5 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -6374,6 +6374,40 @@ void nested_vmx_set_vmcs_shadowing_bitmap(void) } } +/* + * Indexing into the vmcs12 uses the VMCS encoding rotated left by 6. Undo + * that madness to get the encoding for comparison. + */ +#define VMCS12_IDX_TO_ENC(idx) ((u16)(((u16)(idx) >> 6) | ((u16)(idx) << 10))) + +static u64 nested_vmx_calc_vmcs_enum_msr(void) +{ + /* + * Note these are the so called "index" of the VMCS field encoding, not + * the index into vmcs12. + */ + unsigned int max_idx, idx; + int i; + + /* + * For better or worse, KVM allows VMREAD/VMWRITE to all fields in + * vmcs12, regardless of whether or not the associated feature is + * exposed to L1. Simply find the field with the highest index. + */ + max_idx = 0; + for (i = 0; i < nr_vmcs12_fields; i++) { + /* The vmcs12 table is very, very sparsely populated. */ + if (!vmcs_field_to_offset_table[i]) + continue; + + idx = vmcs_field_index(VMCS12_IDX_TO_ENC(i)); + if (idx > max_idx) + max_idx = idx; + } + + return (u64)max_idx << VMCS_FIELD_INDEX_SHIFT; +} + /* * nested_vmx_setup_ctls_msrs() sets up variables containing the values to be * returned for the various VMX controls MSRs when nested VMX is enabled. @@ -6619,8 +6653,7 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps) rdmsrl(MSR_IA32_VMX_CR0_FIXED1, msrs->cr0_fixed1); rdmsrl(MSR_IA32_VMX_CR4_FIXED1, msrs->cr4_fixed1); - /* highest index: VMX_PREEMPTION_TIMER_VALUE */ - msrs->vmcs_enum = VMCS12_MAX_FIELD_INDEX << 1; + msrs->vmcs_enum = nested_vmx_calc_vmcs_enum_msr(); } void nested_vmx_hardware_unsetup(void) diff --git a/arch/x86/kvm/vmx/vmcs.h b/arch/x86/kvm/vmx/vmcs.h index 1472c6c376f7..de3b04d4b587 100644 --- a/arch/x86/kvm/vmx/vmcs.h +++ b/arch/x86/kvm/vmx/vmcs.h @@ -164,4 +164,12 @@ static inline int vmcs_field_readonly(unsigned long field) return (((field >> 10) & 0x3) == 1); } +#define VMCS_FIELD_INDEX_SHIFT (1) +#define VMCS_FIELD_INDEX_MASK GENMASK(9, 1) + +static inline unsigned int vmcs_field_index(unsigned long field) +{ + return (field & VMCS_FIELD_INDEX_MASK) >> VMCS_FIELD_INDEX_SHIFT; +} + #endif /* __KVM_X86_VMX_VMCS_H */ diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h index bb81a23afe89..5e0e1b39f495 100644 --- a/arch/x86/kvm/vmx/vmcs12.h +++ b/arch/x86/kvm/vmx/vmcs12.h @@ -205,12 +205,6 @@ struct __packed vmcs12 { */ #define VMCS12_SIZE KVM_STATE_NESTED_VMX_VMCS_SIZE -/* - * VMCS12_MAX_FIELD_INDEX is the highest index value used in any - * supported VMCS12 field encoding. - */ -#define VMCS12_MAX_FIELD_INDEX 0x17 - /* * For save/restore compatibility, the vmcs12 field offsets must not change. */ -- 2.32.0.288.g62a8d224e6-goog