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 09071C433F5 for ; Sat, 21 May 2022 13:16:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354904AbiEUNQ0 (ORCPT ); Sat, 21 May 2022 09:16:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354795AbiEUNQO (ORCPT ); Sat, 21 May 2022 09:16:14 -0400 Received: from mail-pl1-x636.google.com (mail-pl1-x636.google.com [IPv6:2607:f8b0:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F232A1AF22; Sat, 21 May 2022 06:16:12 -0700 (PDT) Received: by mail-pl1-x636.google.com with SMTP id 10so5990112plj.0; Sat, 21 May 2022 06:16:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=sLeJwTRZqKwsni6KD3sTwNx4zaX7WbD0rQURlwLIxqw=; b=qNYBQUMvmkIWvAFd09B6mjeqs0CZHBIWv1m+/Im5RVDENWdlTn9upvNJbBlTUOHRcN 7C2a6qUjwS23O6suq6mAFVsf7xVcB5stZLNTuQQtjxwQIbrXFhYjNWLYWOR22c9VZe98 t7giFroEmdlXDNQFHZe6GD1lp5yRz3SbLwEdIUfgv2/OxFjzuR59KcBHSYGqaoBNhFw+ NTH7GkrCjlCE+awAsQVa4bftDxTuN02nuUWD3tOHa9oJxDkyTCj99giMoltWN/tz8sRP jZSJT4S4TGWzGBOLoxKPTWokrn+wp2w5YqwuGymjhi8Jt1UYiDXJhH6lWzC+k04dm8Yo O4cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=sLeJwTRZqKwsni6KD3sTwNx4zaX7WbD0rQURlwLIxqw=; b=eRNAnl2NXPpF8twoJsdLsJVWZ/ZEAQN6wFAM8y7HoaTLCl6rpBH5EinYcRTstabzFT hLrqsFOI6wCx9ZQPERi6Uw472LB23yjDvjJBxTjOSNILt+hvsYTsqhJTihIZdc0Kbdkm fqXb4zmHrLb6e404ZZki15e1Kfe/BOw/KAuoQPmu7P8H+ERY0ykls7P73TtyhXNInNC3 PPwP9i3ROoDK7Db20Xy8GClgHkK9LknfUaPbF0vBKoS2tK5+49k5k/wozPWzb0KtnRna SMQGRAz+HdsnZ191257H6mJrE2+E03ToLPs2J/ow5vVsJ849ec9P7jDppdHZlZHBSayw 3kbA== X-Gm-Message-State: AOAM531PvRz918jXoTE4bZMYcH8JBs72kfBTfPkwumHOlbIPPbTUYoXe XJvzaY5i3lVN89vuQj6YL79SttpPy8E= X-Google-Smtp-Source: ABdhPJyK0S8CvG3PwY7JthQT8/D6JlpIGj4RcIl+AZHC7FvxjSCPmxjR+nVOei6lvJu6l9H8jSFfVg== X-Received: by 2002:a17:902:e193:b0:161:e848:ad57 with SMTP id y19-20020a170902e19300b00161e848ad57mr9970313pla.167.1653138972211; Sat, 21 May 2022 06:16:12 -0700 (PDT) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id n9-20020a170902f60900b0015e8d4eb2adsm1528316plg.247.2022.05.21.06.16.11 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 21 May 2022 06:16:12 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Sean Christopherson Cc: Vitaly Kuznetsov , Maxim Levitsky , David Matlack , Lai Jiangshan Subject: [PATCH V3 02/12] KVM: X86/MMU: Add using_local_root_page() Date: Sat, 21 May 2022 21:16:50 +0800 Message-Id: <20220521131700.3661-3-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220521131700.3661-1-jiangshanlai@gmail.com> References: <20220521131700.3661-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lai Jiangshan In some cases, local root pages are used for MMU. It is often using to_shadow_page(mmu->root.hpa) to check if local root pages are used. Add using_local_root_page() to directly check if local root pages are used or needed to be used even mmu->root.hpa is not set. Prepare for making to_shadow_page(mmu->root.hpa) returns non-NULL via using local shadow [root] pages. Signed-off-by: Lai Jiangshan --- arch/x86/kvm/mmu/mmu.c | 40 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 37 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index efe5a3dca1e0..624b6d2473f7 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1690,6 +1690,39 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } +/* + * KVM uses the VCPU's local root page (vcpu->mmu->pae_root) when either the + * shadow pagetable is using PAE paging or the host is shadowing nested NPT for + * 32bit L1 hypervisor. + * + * It includes cases: + * nonpaging when !tdp_enabled (direct paging) + * shadow paging for 32 bit guest when !tdp_enabled (shadow paging) + * NPT in 32bit host (not shadowing nested NPT) (direct paging) + * shadow nested NPT for 32bit L1 hypervisor in 32bit host (shadow paging) + * shadow nested NPT for 32bit L1 hypervisor in 64bit host (shadow paging) + * + * For the first four cases, mmu->root_role.level is PT32E_ROOT_LEVEL and the + * shadow pagetable is using PAE paging. + * + * For the last case, it is + * mmu->root_role.level > PT32E_ROOT_LEVEL && + * !mmu->root_role.direct && mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL + * And if this condition is true, it must be the last case. + * + * With the two conditions combined, the checking condition is: + * mmu->root_role.level == PT32E_ROOT_LEVEL || + * (!mmu->root_role.direct && mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL) + * + * (There is no "mmu->root_role.level > PT32E_ROOT_LEVEL" here, because it is + * already ensured that mmu->root_role.level >= PT32E_ROOT_LEVEL) + */ +static bool using_local_root_page(struct kvm_mmu *mmu) +{ + return mmu->root_role.level == PT32E_ROOT_LEVEL || + (!mmu->root_role.direct && mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL); +} + static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct) { struct kvm_mmu_page *sp; @@ -4252,10 +4285,11 @@ static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu, { /* * For now, limit the caching to 64-bit hosts+VMs in order to avoid - * having to deal with PDPTEs. We may add support for 32-bit hosts/VMs - * later if necessary. + * having to deal with PDPTEs. Local roots can not be put into + * mmu->prev_roots[] because mmu->pae_root can not be shared for + * different roots at the same time. */ - if (VALID_PAGE(mmu->root.hpa) && !to_shadow_page(mmu->root.hpa)) + if (unlikely(using_local_root_page(mmu))) kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT); if (VALID_PAGE(mmu->root.hpa)) -- 2.19.1.6.gb485710b