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 913FDC433DB for ; Mon, 8 Feb 2021 16:51:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37B4164E8F for ; Mon, 8 Feb 2021 16:51:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234562AbhBHQut (ORCPT ); Mon, 8 Feb 2021 11:50:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234681AbhBHQtZ (ORCPT ); Mon, 8 Feb 2021 11:49:25 -0500 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C83CFC06178C for ; Mon, 8 Feb 2021 08:48:44 -0800 (PST) Received: by mail-pf1-x44a.google.com with SMTP id z10so10944256pfa.1 for ; Mon, 08 Feb 2021 08:48:44 -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=CWLS3iCdl7avu6UrS/4a9Q7lCozs1sxuZ+Q+3TdBAr4=; b=MkS/AQpsy4KJi2RAXDyDVdKnFaGcb8SW96N1xaxNIG/R8e6YcwlBQ9vh0t51rhuofi i2vBYteTnMD+u7upnr9YfcoJu3W8ZaYEvYWAQArs9ud8ocrYGqh9b6UKHfUE0aTX2nd+ X7EQW1I5ERB5Wy2/NAVTjwKHNbol9Y4O97ag3nwYL6j0+jshBjpP0zCchaUV1eomWmUm gU1ntF6fsqDAWh40hku88WgSOyoCs6I8fVL/b22dS+pJLvCZ9gVrCi5QEWlnU2rpV7Hk yDcUZ0z49g+Fy7AdPfB8khbpopSxyhugyzcqDYjYRFCRfOSB3i2a3ZzHLoQinzIaMpVG n3zA== 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=CWLS3iCdl7avu6UrS/4a9Q7lCozs1sxuZ+Q+3TdBAr4=; b=kxY4SFw1qupP4vwErba5Q+dMe65lCQ7kcskWf8jeEnNv20Se7km7u86jCFvb9UI32m j+u1swR+P7h1aqoMOr9THDsrfk2kZUShOnwStrfxOGxtXLsN+aKWv+NrADxq1Ww2gjq9 VKnRmZMeQ0MHWK9BaesZHQ3XF6UlujIbPjF51vZ0dKUxaTu0FrBHkM3K0G6ThuZFCMaR 2fEMIDe7ioVSRQgCYBpztSV0ErtnEj6O6a2X68bnXmOwbOIzaKTj+yFTo1+oheHLj2Jm OwoM67dlO/hYeA3PpSQJDRzALkXU9l+ijuB5MrX2Lfhs7N7ZjDDBpwRwLFuXFqv5xGAK k0/A== X-Gm-Message-State: AOAM532tbYCP2UDZ6AXjlUjPCa+fWVEKMwTy6apOIpp9pIsJ74IRhV+r TsC3EBGKKGIQ8ppZikxhBLqk1sc9nP4= X-Google-Smtp-Source: ABdhPJzsbIldQf/8UDs4hDwDDcUOVrtcG212tLSgbSxhCz6lTXYVMBAf80R68i/GgR8Gx2bdiBy8lRKlNSg= Sender: "pgonda via sendgmr" X-Received: from pgonda1.kir.corp.google.com ([2620:0:1008:11:588:a801:402d:d5e5]) (user=pgonda job=sendgmr) by 2002:a17:902:9009:b029:dc:52a6:575 with SMTP id a9-20020a1709029009b02900dc52a60575mr16415595plp.57.1612802924247; Mon, 08 Feb 2021 08:48:44 -0800 (PST) Date: Mon, 8 Feb 2021 08:48:40 -0800 Message-Id: <20210208164840.769333-1-pgonda@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog Subject: [PATCH for 4.19] Fix unsynchronized access to sev members through svm_register_enc_region From: Peter Gonda To: stable@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, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org commit 19a23da53932bc8011220bd8c410cb76012de004 upstream. 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/ Message-Id: <20210127161524.2832400-1-pgonda@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 2b506904be02..93c89f1ffc5d 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1830,6 +1830,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr, struct page **pages; unsigned long first, last; + lockdep_assert_held(&kvm->lock); + if (ulen == 0 || uaddr + ulen < uaddr) return NULL; @@ -7086,12 +7088,21 @@ static 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 (!region->pages) { ret = -ENOMEM; + mutex_unlock(&kvm->lock); goto e_free; } + region->uaddr = range->addr; + region->size = range->size; + + mutex_lock(&kvm->lock); + 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 @@ -7100,13 +7111,6 @@ static 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: -- 2.30.0.478.g8a0d178c01-goog