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=-26.2 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=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 DFB98C433DB for ; Wed, 27 Jan 2021 16:18:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F75120789 for ; Wed, 27 Jan 2021 16:18:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237076AbhA0QSN (ORCPT ); Wed, 27 Jan 2021 11:18:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343968AbhA0QQQ (ORCPT ); Wed, 27 Jan 2021 11:16:16 -0500 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 2EEDEC0613D6 for ; Wed, 27 Jan 2021 08:15:28 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id i82so2728251yba.18 for ; Wed, 27 Jan 2021 08:15:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=9Xv60zVJdPCczqkiRxegMesI9/uXHmAEZHHrmplL1fM=; b=cVjd1wyoIvpXTMR4bPebeDTtMe139pQg6Wa7VaGTxksODku3ExYKVjBYZ6K0bOKjzI bvqP6vAWovpeMRFmcg+7WffIPRoHkZKhTNX+c8fQfIcYjuLInGCZkojObUExOqjK/wJ1 VMG1DUU0CYg28ug47YripMY+WUH5knRtVZfKW3/oIhNtL3AD0+Iv2gtrPxQvBMoFsfUq xuaooUZCrVsbefjPisTntTed6/5heZKc0JX/iEuJOvh9rK8QCUIPslHTGkRZwwLARad0 OI0oS3+VxNZXD4dajHNoYAlhPZaIYcE0AEVBvoVtxEUXYV2gsfqofKmfNIlG0JEkcvod LuAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=9Xv60zVJdPCczqkiRxegMesI9/uXHmAEZHHrmplL1fM=; b=oyj3aMxlNussWlCrqIX5p7JpjpxlV8zEj94szQBS1WO5vYtHXxsHWxuvB0oJXUWoLM Afx8+YXz12Tj89wK6i9Lf/Kz1GxlIWKsVpFyGKBVDRENORDmbhTB5+rPwlLLfX8T9PeW nDL/U0sxlHHWPGI9wMysspwVchsaDVrwZQ2IsZU/3rdB3K2w/yB4is/kP3MJ4zNcb4Na De38w0FOdkpZctaCUb/Z/9O59bFnmRQvUUqM+dvLHQ3KMtDo4BfiCdeE7dRWEX1FPATh o4EUlZ5sOK95Xw2hMm7k/Zj0XnGf6GTuJyhmsbxN8TzezoHhV+Mg9IQYTtHwJ8qLMF6T AKhg== X-Gm-Message-State: AOAM532bySFcDuJ2cxOQGNxLLsJz7m95IxtXD34O7KdMlCPMJkLWXm1n yUVQA9GRfLnMK7iTIqiefEkMk6TwMnc= X-Google-Smtp-Source: ABdhPJxOVxm2ehXpuCNpDGvZJ1wvSjsZNmmaqdqSiL7GiFVkCM8pySxbBDfTAkaDvqqyjKZCrZsktPlhq8o= Sender: "pgonda via sendgmr" X-Received: from pgonda1.kir.corp.google.com ([2620:0:1008:11:f693:9fff:fef4:e3a2]) (user=pgonda job=sendgmr) by 2002:a25:f20b:: with SMTP id i11mr17672537ybe.273.1611764127400; Wed, 27 Jan 2021 08:15:27 -0800 (PST) Date: Wed, 27 Jan 2021 08:15:24 -0800 Message-Id: <20210127161524.2832400-1-pgonda@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.280.ga3ce27912f-goog Subject: [PATCH V2] Fix unsynchronized access to sev members through svm_register_enc_region From: Peter Gonda To: kvm@vger.kernel.org Cc: Peter Gonda , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Paolo Bonzini , Joerg Roedel , Tom Lendacky , Brijesh Singh , Sean Christopherson , x86@kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Grab kvm->lock before pinning memory when registering an encrypted region; sev_pin_memory() relies on kvm->lock being held to ensure correctness when checking and updating the number of pinned pages. Add a lockdep assertion to help prevent future regressions. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Tom Lendacky Cc: Brijesh Singh Cc: Sean Christopherson Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: 1e80fdc09d12 ("KVM: SVM: Pin guest memory when SEV is active") Signed-off-by: Peter Gonda V2 - Fix up patch description - Correct file paths svm.c -> sev.c - Add unlock of kvm->lock on sev_pin_memory error V1 - https://lore.kernel.org/kvm/20210126185431.1824530-1-pgonda@google.com/ --- arch/x86/kvm/svm/sev.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index c8ffdbc81709..b80e9bf0a31b 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -342,6 +342,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr, unsigned long first, last; int ret; + lockdep_assert_held(&kvm->lock); + if (ulen == 0 || uaddr + ulen < uaddr) return ERR_PTR(-EINVAL); @@ -1119,12 +1121,20 @@ int svm_register_enc_region(struct kvm *kvm, if (!region) return -ENOMEM; + mutex_lock(&kvm->lock); region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, 1); if (IS_ERR(region->pages)) { ret = PTR_ERR(region->pages); + mutex_unlock(&kvm->lock); goto e_free; } + region->uaddr = range->addr; + region->size = range->size; + + list_add_tail(®ion->list, &sev->regions_list); + mutex_unlock(&kvm->lock); + /* * The guest may change the memory encryption attribute from C=0 -> C=1 * or vice versa for this memory range. Lets make sure caches are @@ -1133,13 +1143,6 @@ int svm_register_enc_region(struct kvm *kvm, */ sev_clflush_pages(region->pages, region->npages); - region->uaddr = range->addr; - region->size = range->size; - - mutex_lock(&kvm->lock); - list_add_tail(®ion->list, &sev->regions_list); - mutex_unlock(&kvm->lock); - return ret; e_free: -- 2.30.0.280.ga3ce27912f-goog