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, URIBL_BLOCKED,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 C8063C43217 for ; Thu, 14 Jan 2021 01:48:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8331E2343E for ; Thu, 14 Jan 2021 01:48:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728484AbhANBsr (ORCPT ); Wed, 13 Jan 2021 20:48:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729927AbhANAi0 (ORCPT ); Wed, 13 Jan 2021 19:38:26 -0500 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 8DB58C061795 for ; Wed, 13 Jan 2021 16:37:37 -0800 (PST) Received: by mail-qt1-x849.google.com with SMTP id i13so2971994qtp.10 for ; Wed, 13 Jan 2021 16:37:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=+lfNaOH1CNuPDcxuYVHAHObVf+9wEEDIr0zVJxlAHxg=; b=gIjihO2I8gwcFheB4YOs8u4uVfZFwXse/1YgRjreNWQX/e2LFZ9vHhNU3O2UbMJppT hbZqpHYf8uNM9lVGC2jEABPKdK+55wkuZSf/POIfMsZ5LvFBacWcKJNaPDRCFWSRout+ uMFxXkDz0idqm68ZyJ+iooMcEsfRvxeGZcE3jvqoHKICY5e/jlJ/Ce3WTRib5aCm+2mn UAxR2lfbyXAMgnM+w0ZAZdihFN2j4rNDsAn9pUY2X9QzpGeBGYiPFnqtIdSFRglaIAJC iory/Ch11tHGh9uc9FOYACz9x3TLLUhe0ZhJRFn9WwPDIRkKFroNhMwGXCzZWhWHkV8f 7GRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=+lfNaOH1CNuPDcxuYVHAHObVf+9wEEDIr0zVJxlAHxg=; b=tfzREh7xK1qNNvJ5jljtBgFwKr6ZttMciTj6W5KzL5zB8X1gvif37cn0ha5AMZ78O2 AlJDefGjzWTxWAjiBU/Diyi/KC+FahZ55RG7bJNbh0JSsBCENOwvpXJymu6z3OCVdl8V bz+oDVnvfxgWY+aDsEmS7QZgBO9QIwf/iYvsdyZgBH1FU/H4y2ZgyGkHBZ9cQwkkkvv9 XMcZZbBbAfCe9ONZWb2y/c6y0aZY9LOpRhnmRg/bD16t4wV1q0hLHNEixc+hV4x8sQmx jR5XN1DGG2sjH4/UY6V/Po6cc8mUUE2T+Tejx8+N4eIze0QtEWY9oqV9rS2SGNLHZHXy ncog== X-Gm-Message-State: AOAM5303/OkbfDPoprTEsE6q2axUt0+V+4xeCQ4dYwPKc9cZGBi7Ycqq GgHBF7XCHLEuLjcmlJG32rF4yz+Y4VE= X-Google-Smtp-Source: ABdhPJz6SZlx5VJJIc17Aooj99sknhXwjukqTwoNewwxv6DIs9ZCRWUkLmY0rTV2mz8FiqTixYZn5yW997c= Sender: "seanjc via sendgmr" X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:1ea0:b8ff:fe73:50f5]) (user=seanjc job=sendgmr) by 2002:a25:8b:: with SMTP id 133mr7308631yba.513.1610584656762; Wed, 13 Jan 2021 16:37:36 -0800 (PST) Reply-To: Sean Christopherson Date: Wed, 13 Jan 2021 16:36:55 -0800 In-Reply-To: <20210114003708.3798992-1-seanjc@google.com> Message-Id: <20210114003708.3798992-2-seanjc@google.com> Mime-Version: 1.0 References: <20210114003708.3798992-1-seanjc@google.com> X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v2 01/14] KVM: SVM: Zero out the VMCB array used to track SEV ASID association From: Sean Christopherson To: Paolo Bonzini , Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov , Tom Lendacky , Brijesh Singh Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Zero out the array of VMCB pointers so that pre_sev_run() won't see garbage when querying the array to detect when an SEV ASID is being associated with a new VMCB. In practice, reading random values is all but guaranteed to be benign as a false negative (which is extremely unlikely on its own) can only happen on CPU0 on the first VMRUN and would only cause KVM to skip the ASID flush. For anything bad to happen, a previous instance of KVM would have to exit without flushing the ASID, _and_ KVM would have to not flush the ASID at any time while building the new SEV guest. Cc: Borislav Petkov Cc: Tom Lendacky Cc: Brijesh Singh Fixes: 70cd94e60c73 ("KVM: SVM: VMRUN should use associated ASID when SEV is enabled") Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/svm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 7ef171790d02..ccf52c5531fb 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -573,7 +573,7 @@ static int svm_cpu_init(int cpu) if (svm_sev_enabled()) { sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1, sizeof(void *), - GFP_KERNEL); + GFP_KERNEL | __GFP_ZERO); if (!sd->sev_vmcbs) goto free_save_area; } -- 2.30.0.284.gd98b1dd5eaa7-goog